INTEGRATED CANOPY MANAGEMENT IN CALIFORNIA NUT CROPS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0188866
• Project No.: CA-D-PLS-6885-H
• Project Start Date: Oct 1, 2011
• Project End Date: Sep 30, 2016

Project Director
Lampinen, B.

Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671

Performing Department
Plant Sciences

Non Technical Summary
Situation: The increasingly competitive marketplace for tree nuts and consumer demands to decrease pesticide use is pushing growers to increase planting density and push trees into early productivity while trying to minimize pesticide use. The resulting high density planting can increase food safety risk due to cool, moist conditions on the orchard floor being conducive to microbe growth. Purpose: The purpose of this work is to examine the role of tree training and pruning on long term orchard structure and productivity with the goal of maintaining sustainable productivity in high density plantings. A secondary goal is to investigate the role of canopy management and irrigation on food safety risk in nut crops.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	1212	1060	20%
102	1213	1060	20%
205	1212	1060	20%
205	1213	1060	20%
712	1212	1060	20%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 205 - Plant Management Systems; 712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins;

Subject Of Investigation
1212 - Almond; 1213 - Walnut;

Field Of Science
1060 - Biology (whole systems);

Keywords

canopy management

regulated deficit irrigation

tree training

tree pruning

food safety risk

root growth

Goals / Objectives
1) Work to maintain productivity in dense plantings. 2) Assess possibilities of using regulated deficit irrigation and nitrogen manipulation to attempt to regulate vegetative growth. 3) Investigate the role of role of irrigation and canopy management on food safety risk. 4) Investigate the role of tree training on root growth patterns, canopy structure and productivity.

Project Methods
Field studies will be used to investigate methods of maintaining productivity in high density plantings and the role of irrigation and canopy management in disease and insect resistance as well as food safety risk. Additional work will involve the impacts of different tree training and pruning methods on root growth patterns, long term canopy development and productivity. This work will include detailed investigations of the impacts of training and pruning methods on canopy light interception as measured with a new mobile platform we have developed as well as root growth observations using mini-rhizotron tubes. This information will be used to help develop integrated orchard management practices to maintain productivity while minimizing inputs.

Progress 10/01/11 to 09/30/16

Outputs
Target Audience:he target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have provided training related to canopy management and irrigation to growers, farm advisors and crop consultants during the review period How have the results been disseminated to communities of interest?Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. What do you plan to do during the next reporting period to accomplish the goals?Work will continue summarizing results from the spur dynamics project. Work will continue with the mobile platform lightbar for measuring canopy light interception with the goal of understanding productivity relationships to pruning, irrigation management, etc. The iPhone app for measuring canopy light interception was released to farm advisors and selected growers and will be released in the Apple store in the spring of 2016.

Impacts
What was accomplished under these goals? Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2014 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 4 years of similar levels of water and nitrogen application. Although field work on this objective is a largely completed, work is continuing on analyzing data and preparing it for publication. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2015. Results in 2008-2015 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 and results through the 2015 season showed similar cumulative yields for the unpruned compared to the heavily pruned trees. The results from these trials has been reported at the Annual Almond Industry Conference in Sacramento, the Walnut Conference in Bodega Bay, Nickels Field Day, an annual grower field day at the site, as well as numerous farm advisor winter and summer field meetings. Objective 5. The mobile platform was used extensively during the 2009-2016 seasons to map midday light interception in approximately 20 almond orchards and 20 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. Deficit water managment combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009-2016 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2016 seasons. In 2011 through 2013, the light bar was used in high density olive trials in California as well as in hazelnuts in Oregon in 2011 and 2012. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day as well as at a hazelnut grower meeting in Oregon. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State and at least one more is being planned in Australia. An iPhone app is currently being developed that will allow growers to estimate midday canopy light interception and hence yield potential in real time in the orchard. The iPhone app was released to farm advisors and select growers in the spring of 2015 and the final release in the Apple store is planned for the spring of 2016. The iPhone app was released in the Apple store in the fall of 2016 under the iPAR.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Tombesi, Sergio. Bruce D. Lampinen, Samuel Metcalf, and Theodore M. DeJong. 2016. Yield in almond is related more to the abundance of flowers than the relative number of flowers that set fruit. California Agriculture, http://calag.ucanr.edu " PUBLISHED ONLINE NOVEMBER 16, 2016
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Couvreur, V., M.M. Kandelous, B.L. Sanden, B.D. Lampinen, and J.W. Hopmans. 2016. Downscaling transpiration rate from field to tree scale. Agricultural and Forest Meteorology 221: 71-77.

Progress 10/01/14 to 09/30/15

Outputs
Target Audience:The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have provided training related to canopy management and irrigation to growers, farm advisors and crop consultants during the review period How have the results been disseminated to communities of interest?Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. What do you plan to do during the next reporting period to accomplish the goals?Work will continue summarizing results from the spur dynamics project. Work will continue with the mobile platform lightbar for measuring canopy light interception with the goal of understanding productivity relationships to pruning, irrigation management, etc. The iPhone app for measuring canopy light interception was released to farm advisors and selected growers and will be released in the Apple store in the spring of 2016.

Impacts
What was accomplished under these goals? Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2014 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 4 years of similar levels of water and nitrogen application. Although field work on this objective is a largly completed, work is continuing on analyzing data and preparing it for publication. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2015. Results in 2008-2015 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 and results through the 2015 season showed similar cumulative yields for the unpruned compared to the heavily pruned trees. The results from these trials has been reported at the Annual Almond Industry Conference in Sacramento, the Walnut Conference in Bodega Bay, Nickels Field Day, an annual grower field day at the site, as well as numerous farm advisor winter and summer field meetings. Objective 5. The mobile platform was used extensively during the 2009-2015 seasons to map midday light interception in approximately 20 almond orchards and 20 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009-2015 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2015 seasons. In 2011 through 2013, the light bar was used in high density olive trials in California as well as in hazelnuts in Oregon in 2011 and 2012. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day as well as at a hazelnut grower meeting in Oregon. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State and at least one more is being planned in Australia. An iPhone app is currently being developed that will allow growers to estimate midday canopy light interception and hence yield potential in real time in the orchard. The iPhone app was released to farm advisors and select growers in the spring of 2015 and the final release in the Apple store is planned for the spring of 2016.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Zarate-Valdez, Jose L., Samuel Metcalf, William Stewart, Susan L. Ustin, and Bruce Lampinen. 2015. Estimating light interception in tree crops with digital images of canopy shadow. Precision Agriculture DOI 10.1007/s11119-015-9387-8 (published online 24 January 2015). 16 pages.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Zarate-Valdez, Jose L., Saiful Muhammad, Sebastian Saa, Bruce D. Lampinen and Patrick H. Brown. 2015. Light interception, leaf nitrogen and yield prediction in almonds: A case study. European Journal of Agronomy 66: 1-7.
• Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Tombesi, Sergio, Bruce D. Lampinen, Samuel Metcalf and Theodore M. DeJong. 2015. Spur fruit set is negatively related with current-year spur leaf area in almond. HortSci. 50(2): 1-4.

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. In addition I attended and presented at a hazelnut grower meeting in Oregon with ~250 growers attending. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? We have provided training related to canopy management and irrigation to growers, farm advisors and crop consultants during the review period How have the results been disseminated to communities of interest? Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. In addition I attended and presented at a hazelnut grower meeting in Oregon with ~250 growers attending. What do you plan to do during the next reporting period to accomplish the goals? Work will continue summarizing results from the spur dynamics project. Work will continue with the mobile platform lightbar for measuring canopy light interception with the goal of understanding productivity relationships to pruning, irrigation management, etc. The iPhone app for measuring canopy light interception will be released to farm advisors and growers.

Impacts
What was accomplished under these goals? Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2014 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 4 years of similar levels of water and nitrogen application. Although field work on this objective is a largly completed, work is continuing on analyzing data and preparing it for publication. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2014. Results in 2008-2014 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 and results through the 2014 season showed significantly higher cumulative yield for the unpruned compared to the heavily pruned trees. The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, an annual grower field day at the site, as well as numerous farm advisor winter and summer field meetings. Objective 5. The mobile platform was used extensively during the 2009-2014 seasons to map midday light interception in approximately 20 almond orchards and 20 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009-2014 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2014 seasons. In 2011 through 2013, the light bar was used in high density olive trials in California as well as in hazelnuts in Oregon in 2011 and 2012. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day as well as at a hazelnut grower meeting in Oregon. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State. An iPhone app is currently being developed that will allow growers to estimate midday canopy light interception and hence yield potential in real time in the orchard. The iPhone app will be released to farm advisors and select growers in the spring of 2015.

Publications

• Type: Conference Papers and Presentations Status: Accepted Year Published: 2012 Citation: Lampinen, B., S. Upadhyaya, V. Udompetaikul, G. Browne, J. Roach, S. Metcalf, W. Stewart, L. Contador, C. Negr�n, I. P. G�mez, B. Beede, C. DeBuse, D. Doll, R. Duncan, J. Edstrom, R. Elkins, E. Fichtner, J. Grant, J. Hasey, B. Holtz, K. Kelley, B. Krueger, F. Niederholzer, and J. Olson. 2014. A second generation mobile platform for assessing midday canopy photosynthetically active radiation interception in orchard systems. Proceedings of the Tenth International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems. Stellenbosch, South Africa Dec. 3-6, 2012. Editor K. Theron. Acta Hort. 1058: 105-112.
• Type: Journal Articles Status: Accepted Year Published: 2013 Citation: Negron, Claudia, Loreto Contador, Bruce D. Lampinen, Samuel G. Metcalf, Yann Guedon, Evelyne Costes and Theodore M. DeJong. 2013. Differences in proleptic and epicormic shoot structures in relation to water deficit and growth rate in almond trees (Prunus dulcis). Ann. Bot. online 10 pages.
• Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Tombesi, Sergio, Bruce D. Lampinen, Samuel Metcalf, and Theodore M. DeJong. 2015. Spur fruit set is negatively related with current-year spur leaf area in almond. HortSci 50(2): 1-4.

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Objective 1- In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2012 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 4 years of similar levels of water and nitrogen application. Although field work on this objective is a largly completed, work is continuing on analyzing data and preparing it for publication. Objective 2- Results in 2008-2013 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 3- The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, an annual grower field day at the site, as well as numerous farm advisor winter and summer field meetings. Objective 4- These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. What do you plan to do during the next reporting period to accomplish the goals? An iPhone app is currently being developed that will allow growers to estimate midday canopy light interception and hence yield potential in real time in the orchard. The iPhone app is planned for trials with farm advisors and select growers this summer.

Impacts
What was accomplished under these goals? Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers’ desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009-2013 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2013 seasons. In 2011 and 2012, the light bar was used in high density olive trials in California as well as in hazelnuts in Oregon. This information has been extended at numerous industry conferences, Farm Advisor’s county meetings and the Nickels Soil Laboratory Field Day. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State. The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 1- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. Objective 2- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2013. Objective3- Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 and results through the 2013 season again showed significantly higher cumulative yield for the unpruned compared to the heavily pruned trees. Objective 4. The mobile platform was used extensively during the 2009-2013 seasons to map midday light interception in approximately 20 almond orchards and 20 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Browne, Greg T., Bruce D. Lampinen, Brent A. Holtz, David A. Doll, Shrinivasa K. Upadhyaya, Leigh S. Schmidt, Ravindra G. Bhat, Vasu Udompetaikul, Robert W. Coates, Bradley D. Hanson, Karen M. Klonsky, Suduan Gao, Dong Wang, Matt Gillis, James S. Gerik, and R. Scott Johnson. 2013. Managing the almond and stone fruit replant disease complex with less soil fumigant. California Agriculture. 67(3): 127-137.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2012 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 4 years of similar levels of water and nitrogen application. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2012. Results in 2008-2012 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 and results through the 2012 season again show no benefits of pruning. The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, an annual grower field day at the site, as well as numerous farm advisor winter and summer field meetings. Objective 5. The mobile platform was used extensively during the 2009-2012 seasons to map midday light interception in 19 almond orchards and 18 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. PARTICIPANTS: Dr. Greg Browne Plant Pathology - CAES One Shields Avenue Plant Pathology 354 Hutchison Hall Davis, CA 95616-8680 [phone] Fax: [phone] Bob Curtis, Research Director The Almond Board of California 1150 Ninth Street, Suite 1500 Modesto, CA 95354 Dr. Ted DeJong Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Kenneth Shackel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 John Edstrom UCCE Colusa County PO Box 180, 100 Sunrise Boulevard Suite E Colusa, CA 95932 [phone] Fax: [phone] Rachel Elkins UCCE Lake County Ag Center, 883 Lakeport Blvd. Lakeport, CA 95453 [phone] Dr. Tom Gradziel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Joe Grant UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Janine Hasey UCCE Yuba/Sutter Counties 142 Garden Highway County Agricultural Building Suite A Yuba City, CA 95991-5512 [phone] Fax: [phone] Dr. Brent Holtz County Director UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Dr. Gale McGranahan Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Joe McIlvaine Paramount Farming Company 33141 E. Lerdo Highway Bakersfield, CA 93308 Dr. Themis Michailides Dept. of Plant Pathology UC Davis Kearney Agricultural Center 9240 S. Riverbend Ave. Kearney Ag. Center Parlier, CA 93648 Dr. David Ramos, Research Director California Walnut Board 101 Parkshore Drive, Suite 250 Folsom, CA 95630 Phone: [phone] Fax: [phone] Dr. Shrini Upadhyaya Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 Dr. David Slaughter Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 TARGET AUDIENCES: The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009-2012 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2012 seasons. In 2011 and 2012, the light bar was used in high density olive irrigation and deficit irrigation trials as well. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State. An iPhone app is currently being developed that will allow growers to estimate midday canopy light interception and hence yield potential in real time in the orchard.

Publications

• Lampinen, Bruce D., Vasu Udompetaikul, Gregory T. Browne, Samuel G. Metcalf, William L. Stewart, Loreto Contador, Claudia Negron, and Shrini K. Upadhyaya. 2012. A mobile platform for measuring canopy photosynthetically active radiation interception in orchard systems. HortTechnology 22: 237-244. [cover photo]
• Zarate-Valdez, Jose L., Michael L. Whiting, Bruce D. Lampinen, Samuel Metcalf, Susan L. Ustin, and Patrick H. Brown. 2012. Prediction of leaf area index in almonds by vegetation indexes. Computers and Electronics in Agriculture 85: 24-32.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Yields from 2008-2011 yields for the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after 3 years of similar levels of water and nitrogen application. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2011. Results in 2008-2011 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. A second pruned versus unpruned trial was started in 2009 with similar results to those from the earlier described Howard trial showing no benefits of pruning. The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, as well as numerous farm advisor winter and summer field meetings. Objective 5. The mobile platform was used extensively during the 2009 and 2010 seasons to map midday light interception in 19 almond orchards and 18 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc. PARTICIPANTS: Dr. Greg Browne Plant Pathology - CAES One Shields Avenue Plant Pathology 354 Hutchison Hall Davis, CA 95616-8680 [phone] Fax: [phone] Bob Curtis, Research Director The Almond Board of California 1150 Ninth Street, Suite 1500 Modesto, CA 95354 Dr. Ted DeJong Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Kenneth Shackel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 John Edstrom UCCE Colusa County PO Box 180, 100 Sunrise Boulevard Suite E Colusa, CA 95932 [phone] Fax: [phone] Rachel Elkins UCCE Lake County Ag Center, 883 Lakeport Blvd. Lakeport, CA 95453 [phone] Dr. Tom Gradziel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Joe Grant UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Janine Hasey UCCE Yuba/Sutter Counties 142 Garden Highway County Agricultural Building Suite A Yuba City, CA 95991-5512 [phone] Fax: [phone] Dr. Brent Holtz County Director UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Dr. Gale McGranahan Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Joe McIlvaine Paramount Farming Company 33141 E. Lerdo Highway Bakersfield, CA 93308 Dr. Themis Michailides Dept. of Plant Pathology UC Davis Kearney Agricultural Center 9240 S. Riverbend Ave. Kearney Ag. Center Parlier, CA 93648 Dr. David Ramos, Research Director California Walnut Board 101 Parkshore Drive, Suite 250 Folsom, CA 95630 Phone: [phone] Fax: [phone] Dr. Shrini Upadhyaya Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 Dr. David Slaughter Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 TARGET AUDIENCES: The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow canopy size to be maintained at a level that balances productivity with food safety risk. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009 and 2010 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009-2011 season. In 2011, the light bar was used in high density olive irrigation and deficit irrigation trials as well. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day. The interest in this work is also evident in the fact that similar light bars (based on our design) have been built in Arizona and Washington State and one is also being constructed in Australia for the coming field season.

Publications

• Tombesi, Sergio, Bruce D. Lampinen, Samuel Metcalf and Theodore M. DeJong. 2011. Relationships between spur- and orchard-level fruit bearing in almond (Prunus dulcis). Tree Physiology 31: 1413-1421.
• Lampinen, B.D., Sergio Tombesi, Samuel G. Metcalf, and Theodore M. DeJong. 2011. Spur behavior in almond trees: relationships between previous year spur leaf area, fruit bearing and mortality. Tree Physiology 31: 700-706.
• Fulton, Allan, Larry Schwankl, Kris Lynn, Bruce Lampinen, John Edstrom, and Terry Pritchard. 2011. Using EM and VERIS technology to assess land suitability for orchard and vineyard development. Irrigation Science 29: 497-512.
• Hamby, Kelly, Ling Wang Gao, Bruce Lampinen, Thomas Gradziel and Frank Zalom. 2011. Hull split date and shell seal in relation to navel orangeworm (Lepidoptera: Pyralidae) infestation in almond. J. Econ. Entomol. 104(3): 965-969.
• Tombesi, S., R. Scalia, J. Connell, B. Lampinen, and T.M. DeJong. 2010. Fruit development in almond as influenced by early Spring temperatures in California. J. Hortic. Sci. Biotech. 85: 317-322.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase (when canopy is filling in) can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Results in 2008-2010 suggest that yields in the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after conversion to equivalent water and nitrogen regimes. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2010. Results in 2008-2010 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. In addition, work is underway evaluating the impact of different types of tarps used during stockpiling on temperature fluctuations and food safety risk. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Data collection is continuing on the longer term impacts of water management on canopy growth and productivity. Objective 4. Over eight years, unpruned Howard walnut trees have had equivalent yields, canopy height growth and midday canopy light interception compared to traditionally pruned trees. The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, as well as numerous farm advisor meetings (both winter indoor and summer field meetings). Objective 5. The mobile platform was used extensively during the 2009 and 2010 seasons to map midday light interception in 19 almond orchards and 18 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. These data are proving to be useful in evaluating relative productivity of new varieties, impacts of fumigation on canopy growth as well as productivity per unit light intercepted, impacts of pruning and mechanical hedging on light interception and potential productivity, etc PARTICIPANTS: Dr. Greg Browne Plant Pathology - CAES One Shields Avenue Plant Pathology 354 Hutchison Hall Davis, CA 95616-8680 [phone] Fax: [phone] Bob Curtis, Research Director The Almond Board of California 1150 Ninth Street, Suite 1500 Modesto, CA 95354 Dr. Ted DeJong Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Kenneth Shackel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 John Edstrom UCCE Colusa County PO Box 180, 100 Sunrise Boulevard Suite E Colusa, CA 95932 [phone] Fax: [phone] Rachel Elkins UCCE Lake County Ag Center, 883 Lakeport Blvd. Lakeport, CA 95453 [phone] Dr. Tom Gradziel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Joe Grant UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Janine Hasey UCCE Yuba/Sutter Counties 142 Garden Highway County Agricultural Building Suite A Yuba City, CA 95991-5512 [phone] Fax: [phone] Dr. Brent Holtz County Director UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Dr. Gale McGranahan Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Joe McIlvaine Paramount Farming Company 33141 E. Lerdo Highway Bakersfield, CA 93308 Dr. Themis Michailides Dept. of Plant Pathology UC Davis Kearney Agricultural Center 9240 S. Riverbend Ave. Kearney Ag. Center Parlier, CA 93648 Dr. David Ramos, Research Director California Walnut Board 101 Parkshore Drive, Suite 250 Folsom, CA 95630 Phone: [phone] Fax: [phone] Dr. Shrini Upadhyaya Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 Dr. David Slaughter Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 TARGET AUDIENCES: The target audiences for this project have included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow equivalent productivity with potentially decreased food safety risk as the orchard matures. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile light bar in 2009 and 2010 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allow new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009 and 2010 season. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day. The interest in this work is also evident in the fact that similar light bars (based on our design) are being built in Arizona, Washington State, and Australia for the coming field seasons.

Publications

• Tombesi, S., R. Scalia, J. Connell, B. Lampinen, and T.M. DeJong. 2010. Fruit development in almond as influenced by early Spring temperatures in California. J. Hortic. Sci. Biotech. 85: 317-322.
• Stavrinides, M.C., K.M. Daane, B.D. Lampinen and N.J. Mills. 2010. Plant water stress, leaf temperature, and spider mite (Acari: Tetranychidae) outbreaks in California vineyards. 2010. Env. Entomol. 39: 1232-1241.
• R. Elkins, D. Suenram, S. Metcalf, and B. Lampinen. 2010. Water management studies in four young Lake County orchards. Walnut Research Reports 2009. California Walnut Board, Folsom, CA 95630-4726. Pp. 89-90.
• B. Lampinen, G. Browne, S. Upadhyaya, V. Udompetaikul, D. Slaughter, S. Metcalf, W. Stewart, L. Contador, R. Duncan, J. Edstrom, B. Holtz, B. Krueger, and F. Neiderholtzer. 2010. Development and testing of a mobile platform for measuring canopy light interception and water stress in almond. Almond Board of California 2009-2010 Annual Report (AlmondBoard.com/Research Reports).
• B. Lampinen, T. Gradziel, S. Metcalf, W. Stewart, M. Contador, M. A. Thorpe, W. Micke, J. Connell, P. Verdegaal, M. Viveros, and P. Shrader. 2010. Field evaluation of almond varieties. Almond Board of California 2009-2010 Annual Report (AlmondBoard.com/Research Reports).

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Objective 1- The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase (when canopy is filling in) can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 9 years to quantify the impacts of treatments on spur longevity. As canopy size differences decrease over time (as the slower growing deficit irrigated trees continue to fill in their allotted space), the deficit treatments may perform better relative to the control. Shell seal has been better in deficit treatments and this may have implications for food safety. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. In the spring of 2008, all treatments were converted to the same nitrogen and water levels which aim for slightly lower levels of water and nitrogen compared to the original high water/high nitrogen treatments. Results in 2008 and 2009 suggest that yields in the former deficit treatments are nearly equal to those in the high water, high nitrogen treatments after conversion to equivalent water and nitrogen regimes. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Work on stockpiling of almonds started in 2007 was continued through 2009. Results in 2008 and 2009 suggested that variability in canopy size across the orchard resulted in significant differences in moisture content of hulls and nuts such that more mold grew on nuts from the more heavily canopied parts of the orchard. Finally, the role of irrigation in almond responses to the almond replant problem is being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Unpruned Howard walnut trees have had slightly higher yields, equivalent height growth and equivalent midday canopy light interception compared to traditionally pruned trees. The results from these trials has been reported at the Annual Almond Industry Conference in Modesto, the Walnut Conference in Bodega Bay, Nickels Field Day, as well as numerous farm advisor meetings (both winter indoor and summer field meetings). Objective 5. The mobile platform was used extensively during the 2009 season to map midday light interception in 19 almond orchards and 18 walnut orchards. Yield data was then collected from the same plots in each orchard and these data are being used to refine the relationship between light interception and yield in these crops. PARTICIPANTS: Dr. Greg Browne Plant Pathology - CAES One Shields Avenue Plant Pathology 354 Hutchison Hall Davis, CA 95616-8680 [phone] Fax: [phone] Bob Curtis, Research Director The Almond Board of California 1150 Ninth Street, Suite 1500 Modesto, CA 95354 Dr. Ted DeJong Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 John Edstrom UCCE Colusa County PO Box 180, 100 Sunrise Boulevard Suite E Colusa, CA 95932 [phone] Fax: [phone] Rachel Elkins UCCE Lake County Ag Center, 883 Lakeport Blvd. Lakeport, CA 95453 [phone] Dr. Tom Gradziel Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Joe Grant UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Janine Hasey UCCE Yuba/Sutter Counties 142 Garden Highway County Agricultural Building Suite A Yuba City, CA 95991-5512 [phone] Fax: [phone] Dr. Brent Holtz County Director UCCE San Joaquin County 2101 E. Earhart Ave., Suite 200 Stockton, CA 95206 [phone] Fax: [phone] Dr. Gale McGranahan Dept. of Plant Sciences Mail Stop #2, Dept. of Plant Sciences University of California Davis, CA 95616 Dr. Joe McIlvaine Paramount Farming Company 33141 E. Lerdo Highway Bakersfield, CA 93308 Dr. Themis Michailides Dept. of Plant Pathology UC Davis Kearney Agricultural Center 9240 S. Riverbend Ave. Kearney Ag. Center Parlier, CA 93648 Dr. David Ramos, Research Director California Walnut Board 101 Parkshore Drive, Suite 250 Folsom, CA 95630 Phone: [phone] Fax: [phone] Dr. Shrini Upadhyaya Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 Dr. David Slaughter Dept. of Biological and Agricultural Engineering University of California Davis, CA 95616 TARGET AUDIENCES: The target audiences for this project has included farm advisors, PCAs, and growers throughout the state of California. Talks have been given related to this project for at least 6-8 annual grower winter meetings and 4-5 annual grower field meetings as well as at the annual walnut and almond meetings. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Data suggests that deficit water and nitrogen treatments in almond may allow equivalent productivity with potentially decreased food safety risk as the orchard matures. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts resulting from lack of fumigation. Work with the mobile lightbar in 2009 showed that the technology was feasible and that the techniques gave new layers of information on canopy/yield relationships. This has allowed the ability to separate out the effects of productivity that results from increase in canopy size from more productivity per unit light intercepted. These techniques will allo new cultivars to be evaluated relative to existing cultivars for productivity per unit canopy light intercepted. Interest in this methodology has been great as evidenced by requests to use it in prunes, pears, pistachio, peach and grape during the 2009 season. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day.

Publications

• Klonsky, K., B. Lampinen and G. Browne. 2009. Economic performance of alternative pre-plant fumigation treatments for almonds. 2009 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Nov. 10-13, 2009. San Diego, CA pp.7-1 to 7-2.
• Lampinen, B., G. Browne, V. Udompetaikul, S. Upadhyaya, D. Slaughter, B. Holtz, S. Metcalf, M. Shafii, and K. Klonsky. 2009. A mobile platform for measuring canopy photosynthetically active radiation interception in tree crops. 2009 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Nov. 10-13, 2009. San Diego, CA pp.30-1 to 30-4.
• Browne, G. B. Holtz, S. Upadhyaya, B. Lampinen, D. Doll, L. Schmidt, J. Edstrom, M. Shafii, B. Hanson, D. Wong, S. Gao and K. Klonsky. 2009. Integrated pre-plant alternatives to methyl bromide for almonds and other stone fruits. 2009 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Nov. 10-13, 2009. San Diego, CA pp.33-1 to 33-4.
• Lampinen, B. G. Browne, S. Upadhyaya, V. Udompetaikul, D. Slaughter, S. Metcalf, R. Duncan, J. Edstrom, B. Holtz, B. Krueger, and F. Neiderholzer. 2009. Development and testing of a mobile platform for measuring canopy light interception and water stress in almond. 2009 Research Proceedings- Almond Board of California, Modesto, CA. pp. 100-106.
• Lampinen, B., J. Adaskaveg, G. Browne, J. Connell, R. Duncan, R. Michailides, and S. Metcalf. 2009. Lower limb dieback in almond. 2009 Research Proceedings- Almond Board of California, Modesto, CA. pp. 178-185.
• Lampinen, B. T. Michailides, J. Thompson, S. Metcalf, D. Morgan, H. Reyes, Y. Luo, and B. Kabak. 2009. Almond stockpile monitoring for aflatoxin potential. 2009 Research Proceedings- Almond Board of California, Modesto, CA. pp. 132-139.
• Lampinen, B. S. Upadhyaya, V. Udompetaikul, G. Browne, D. Slaughter, S. Metcalf, B. Beede, C. DeBuse, J. Caprile, B. Coates, J. Edstrom, R. Elkins, J. Grant, J. Hasey, K. Kelley, and B. Krueger. 2010. Refining the relationship between canopy light interception and yield in walnut. Walnut Research Reports 2009. pp. 103-108.
• Lampinen, B., J. Caprile, W. Coates, C. DeBuse, D. Doll, J. Edstrom, R. Elkins, J. Grant, J. Hasey, B.Holtz, K. Kelly, W. Krueger, G. Browne, G. McGranahan, C. Leslie, S. Metcalf , C. Negron, M. Contador, Y. Bordes, Stan Cutter and D. Ramos. 2010. Walnut Orchard Management: Pilot Projects, Field Testing, Adaptive Research and Problem Solving by C.E. Farm Advisors and Specialists 2009. Walnut Research Reports 2009. pp. 93-100.
• Shackel, K. J. Edstrom, A. Fulton, B. Lampinen, and L. Schwankl. 2009. Drought survival strategies for established almond orchards on shallow soil. 2009 Research Proceedings- Almond Board of California, Modesto, CA. pp. 121-127.
• Lampinen, Bruce, John Edstrom, Dave Ramos, Sam Metcalf, Claudia Negron, and Stan Cutter. 2010. Comparison of growth and productivity of pruned and unpruned young 'Howard' walnut trees as impacted by crop load. Walnut Research Reports 2009. California Walnut Board, Folsom, CA pp. 123-131.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Objective 1- Work is being conducted on influence of pruned or non-pruned treatments on growth and productivity of young Howard walnut trees. Additional work on this objective is being done as part of the almond spur dynamics project. The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase (when canopy is filling in) can result in a canopy structure that is more sustainable from a production and food safety point of view over time. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 8 years to quantify the impacts of treatments on spur longevity. In 2008, all deficit treatments were converted back to the same applications as the high nitrogen, high water treatments. The deficit treatments appear to be producing equivalent or higher yields per unit canopy compared to the control suggesting the canopies may be more sustainable over the long term without mechanical hedging being required for access. Objective 3- The emphasis for this work has shifted somewhat to studying the role of canopy management on food safety risk in almond and nut quality and food safety in walnut. Additional work was started in 2008 looking at the potential role of almond stockpiling in food safety. Finally, the role of irrigation in almond responses to the almond replant problem are being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Unpruned Howard walnut trees have had slightly higher yields, equivalent height growth and midday canopy light interception compared to traditionally pruned trees. Walnut nut quality is directly related to integrated light interception at any given position in the canopy. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers desire. Data suggests that deficit water and nitrogen treatments in almond may allow equivalent or more productivity as the orchard matures. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts of lack of fumigation. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day.

Publications

• Upadhyaya, Shrini K., G.T. Browne, B.D. Lampinen, M. Shafii, V. Udompetaikul. 2008. Tree planting site-specific fumigant application to control almond replant disease. 2008 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Nov. 12-14, 2008. Orlando, Florida pp. 19-1 to 19-3.
• Browne, G., B. Lampinen, B. Holtz, D. Doll, J. Edstrom, L. Schmidt, S. Upadhyaya, M. Shafii, B. Hanson, D. Wong, S. Gao, N. Goodell, and K. Klonsky. Integrated pre-plant alternatives to methyl bromide for almonds and other stone fruits. 2008 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Nov. 12-14, 2008. Orlando, Florida pp.12-1 to 12-4.
• Danyluk, M., M. Nozawa-Inoue, K. Hristova, K. Scow and L. Harris. 2008. Survival and growth of Salmonella Enteritidis PT 30 in almond orchard soils. J. Appl. Microbiol. 104 1391-1399.
• Lampinen, Bruce, Joe Grant, Samuel Metcalf, and Claudia Negron. 2008. Walnut production and quality as influenced by orchard and within tree canopy environment. Walnut Research Reports 2007. Walnut Marketing Board, Folsom, CA, pp. 115-123.
• Lampinen, Bruce, John Edstrom, Dave Ramos, Sam Metcalf, Claudia Negron and Stan Cutter. 2008. Comparison of growth and productivity of pruned and unpruned young Howard walnut trees as impacted by crop load. Walnut Research Reports 2007, Walnut Marketing Board, Sacramento, CA, pp. 127-134.
• Lampinen, Bruce, Ted DeJong, Steve Weinbaum, Sam Metcalf, Claudia Negron, Mario Viveros, Joe McIlvane, Nadav Ravid, and Rob Baker. 2008. Spur Dynamics and Almond Productivity. 2008 Proceedings: Almond Board of California, Modesto, CA, pp. 81-85.

Progress 01/01/07 to 12/31/07

Outputs
Work is being conducted on influence of pruned or non-pruned treatments on growth and productivity of young Howard walnut trees. Additional work on this objective is being done as part of the almond spur dynamics project. The goal of this aspect of the work is to determine if deficit irrigation and nitrogen management during the tree growth phase (when canopy is filling in) can result in a canopy structure that is more sustainable from a production and food safety point of view over time. This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring has been carried out for 7 years to quantify the impacts of treatments on spur longevity. Although all three deficit treatments have led to significantly lower cumulative yields over seven years, yields per unit light intercepted has been similar in all except the treatment which received moderate nitrogen and moderate water, which had significantly lower cumulative yield. This suggests that as canopy size differences decrease over time, the deficit treatments may perform better relative to the control. Also, if deficit irrigated trees had been planted closer together, they might have had relatively higher overall yields compared to the control. Incidence of kernel mold has continued to be less in deficit irrigated trees. Shell seal has also been better in deficit treatments and this may have implications for food safety. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. Objective 3- The emphasis for this work has shifted somewhat and work is now studying the role of canopy management on food safety risk in almond. Additional work was started in 2007 looking at the potential role of almond stockpiling in food safety. Finally, the role of irrigation in almond responses to the almond replant problem are being investigated. Data from this project has shown that water management during the year of planting is essential to minimize negative effects of lack of fumigation. Objective 4. Unpruned Howard walnut trees have had slightly higher yields, equivalent height growth and midday canopy light interception compared to traditionally pruned trees.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers desire. Data suggests that deficit water and nitrogen treatments in almond may allow equivalent or more productivity as the orchard matures. In addition, the deficit treatments appear to result in better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. Preliminary data shows that good irrigation management, particular in the first year of growth is essential to minimizing negative impacts of lack of fumigation. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day.

Publications

• Rosati, A., S.G. Metcalf, R.P. Buchner, A.E. Fulton, and B.D. Lampinen. 2007. Effects of kaolin application on light absorption and distribution, radiation use efficiency and photosynthesis on almond and walnut canopies. Annals of Botany 99: 255-263.
• Shrestha, A., G.T. Browne, Bruce D. Lampinen, Sally Schneider, Leo Simon, and Tom Trout. 2006. Weed species and their emergence patterns under methyl bromide and alternative fumigants in fruit nurseries. 2006 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, November 6-9, 2006, Orlando, Florida. pp. 117-1 to 117-4.
• Danyluk, M., M. Nozawa-Inoue, K. Hristova, K. Scow and L. Harris. 2007. Survival and growth of Salmonella Enteritidis PT 30 in almond orchard soils. In Press, Journal of Applied Microbiology.
• Browne, G., D. Doll, L. Schmidt, J. Connell, B. Holtz, S. Upadhyaya, B. Lampinen, D. Kluepfel, and S. Schneider. 2006. Prunus replant disease in California and its management without methyl bromide. 2006 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, November 6-9, 2006, Orlando, Florida. pp. 64-1 to 64-4.
• Lampinen, B., G. Browne, S. Schneider, A. Shrestha, B. Holtz and L. Simon. 2006. Alternative Pre-plant fumigation treatments for deciduous tree crops. 2006 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, November 6-9, 2006, Orlando, Florida. pp. 39-1 to 39-5.
• Browne, G., B. Lampinen, B. Holtz, S. Upadhyaya, D. Wang, S. Gao, D. Doll, L. Schmidt, B. Hanson, N. Goodell, M. McKenry, and K. Klonsky. Integrated pre-plant alternatives to methyl bromide for almonds and other stone fruits. 2007 Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, Oct. 29-Nov. 1, 2007. Sand Diego, CA pp.8-1 to 8-3.
• Lampinen, Bruce, John Edstrom, Sam Metcalf, Valerie Gamble, Kathy Moore, and Stan Cutter. 2007. Comparison of growth and productivity of pruned and unpruned young "Howard" walnut trees as impacted by crop load. Walnut Research Reports 2006, Walnut Marketing Board, Sacramento, CA, pp. 127-134.

Progress 01/01/06 to 12/31/06

Outputs
Objective 1- Work is being conducted on influence of pruning or non-pruned treatments on growth and productivity of young Howard walnut trees. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring will be carried out for 6 years to quantify the impacts of treatments on spur longevity. All three deficit treatments led to significantly lower yields in the fourth year of treatment imposition. However, if yields per unit light intercepted was calculated, all three deficit treatments had significantly higher yields than the control in 2004 and equivalent yields to the control in 2005. In 2004 through 2006 there were no significant negative impacts on Nonpareil yield per unit midday light interception suggesting as canopy size differences decrease over time, the deficit treatments may perform better relative to the control. This suggests that if deficit irrigated trees had been planted closer together, they might have had higher overall yields compared to the control. Incidence of kernel mold has continued to be less in deficit irrigated trees. Significant changes in leaf specific area (a measure of spur quality), particularly in inner canopy positions in the deficit treatments, may lead to improved spur longevity and shifts in canopy nut production patterns in the coming season. Objective 3- The emphasis for this work has shifted somewhat and work is now being done in studying role of water stress in seasonal variations in plant protective compounds in walnut as well as interactions with mold. In addition, work is being done on the influence of deficit nitrogen and water treatments on shell seal and resulting potential for insect damage and microbial contamination potential. Finally, the role of irrigation in almond responses to the almond replant problem are being investigated. In general, insect and disease susceptibility are directly related to water status with wetter trees tending to have more open shells and higher disease and insect damage. Objective 4. Unpruned Howard walnut trees have had slightly higher yields, equivalent height growth and midday canopy light interception compared to traditionally pruned trees.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers desire. Data suggests that deficit water and nitrogen treatments in almond may allow equivalent or more productivity as the orchard matures. In addition, the deficit treatments appear to better shell seal and this is directly related to insect and disease resistance. Irrigation was shown to have a strong interaction with fumigation and this relationship is continuing to be investigated. This information has been extended at numerous industry conferences, Farm Advisor's county meetings and the Nickels Soil Laboratory Field Day.

Publications

• Brown, G.T. D. Kluepfel, D. Doll, L. Schmidt, P. Shrader, S. Upadhyaya, B. Holtz, B. Lampinen, B. Coates, M. Shafii, M. Giles, J. Connell, S. Metcalf, C. Negron, T. Trout, J. Gartung, S. Schneider, B. Hanson, N. Goodell, C. Rose, R. Catania and P. Domecq. 2006. Biology and management of almond replant disease. 2006 Proceedings, 34th Almond Industry Conference, December 6-7, 2006, Modesto Centre Plaza, Modesto, CA, pp. 150-166.
• Lampinen, Bruce, John Edstrom, Dave Ramos, Sam Metcalf, Claudia Negron and Stan Cutter. 2006. Comparison of growth and productivity of pruned and unpruned young Howard walnut trees as impacted by crop load. Walnut Research Reports 2005, Walnut Marketing Board, Sacramento, CA, pp. 127-132.
• Westerdahl, Becky, Janine Hasey, Joe Grant and Bruce Lampinen. 2006. Nematode Management in Walnut Orchards- 2005. Walnut Research Reports 2005. Walnut Marketing Board, Sacramento, CA, pp. 357-364.
• Lampinen, Bruce, T. DeJong, S. Weinbaum, S. Metcalf, C. Negron,M. Viveros, J. McIlvane, N. Ravid, and R. Baker. 2006. Spur dynamics and almond productivity. 2006 Proceedings, 34th Almond Industry Conference, December 6-7, 2006, Modesto Centre Plaza, Modesto, CA, pp. 113-128.
• Lampinen, B., G. Browne, S. Schneider, A. Shrestha, B. Holtz and L. Simon. 2006. Alternative pre-plant soil fumigation treatments for deciduous tree crops. 2006 Annual International Conference on Methyl Bromide Alternatives and Emissions Reductions. Nov. 6-9, 2006. The Doubletree Hotel, Orlando, Florida. pp. 39-1 to 39-5.

Progress 01/01/05 to 12/31/05

Outputs
Objective 1- Original objective has been completed. Final results were presented in 2003 and final reports are listed below. New work is being conducted on influence of pruning or non-pruned treatments on growth and productivity of young Howard walnut trees. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring will be carried out for 6 years to quantify the impacts of treatments on spur longevity. In 2005, all three deficit treatments had significantly lower midday canopy light interception than the control throughout the season. Once again, midday stem water potentials were maintained near target levels throughout the 2005 season. All three deficit treatments led to significantly lower yields in the fourth year of treatment imposition. However, if yields per unit light intercepted was calculated, all three deficit treatments had significantly higher yields than the control in 2004 and equivalent yields to the control in 2005. This suggests that if deficit irrigated trees had been planted closer together, they might have had higher overall yields compared to the control. Incidence of kernel mold has continued to be less in deficit irrigated trees. Significant changes in leaf specific area (a measure of spur quality), particularly in inner canopy positions in the deficit treatments, may lead to improved spur longevity and shifts in canopy nut production patterns in the coming season. Objective 3- The emphasis for this work has shifted somewhat and preliminary work is now being done in studying role of water stress in seasonal variations in plant protective compounds in walnut as well as interactions with mold. In addition, work is being done on influence of deficit nitrogen and water treatments on shell seal and resulting potential for insect damage and microbial contamination potential.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers' desire. Preliminary data suggests that deficit water and nitrogen treatments in almond may allow an equivalent or more productivity as the orchard matures. This information has been extended at numerous industry conferences as well as Farm Advisor's county meetings.

Publications

• Lampinen, B., W. Coates, J. Edstrom, R. Elkins, J. Grant, J. Hasey, L. Hendricks, W. Krueger, W. Olson, W. Reil, G. Browne, G. McGranahan, B. Teviotdale, S. Metcalf, W. Micke, and J. Yeager. 2005. Walnut orchard management: Pilot projects, field testing, adative research and problem solving by C.E. Farm Advisors and Specialists - 2004. Walnut Research Reports 2004, Walnut Marketing Board, Sacramento, CA, pp. 141-145.
• Lampinen, Bruce, John Edstrom, Sam Metcalf, Valerie Gamble, Kathy Moore, and Stan Cutter. 2005. Comparison of growth and productivity of pruned and unpruned young Howard walnut trees as impacted by crop load. Walnut Research Reports 2004, Walnut Marketing Board, Sacramento, CA, pp. 147-148.
• Browne, G., W. Hackett, B. Krueger, J. Connell, B. Olson, B. Lampinen, S. McLaughlin, R. Lee, D. Potter, J. Grant, G. McGranahan, C. Leslie, and D. Bujazha. 2005. Determining Phytophthora resistance in elite Paradox clones and specific etiology of a Paradox crown and root rot. Walnut Research Reports 2004, Walnut Marketing Board, Sacramento, CA, pp. 379-406.
• Lampinen, Bruce, T. DeJong, S. Weinbaum, S. Metcalf, C. Negron,M. Viveros, J. McIlvane, N. Ravid, and R. Baker. 2005. Spur dynamics and almond productivity. 2005 Proceedings, 33nd Almond Industry Conference, December 7-8, 2005, Modesto Centre Plaza, Modesto, CA, pp. 95-109.

Progress 01/01/04 to 12/31/04

Outputs
Objective 1- Final results on high limb pruning were discussed in last year's report and final reports are listed below. New work is being conducted on influence of pruning or non-pruning treatments on growth and productivity of young Howard walnut trees. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring will be carried out for 6 years to quantify the impacts of treatments on spur longevity. In 2004, all three deficit treatments had significantly lower midday canopy light interception than the control throughout the season. Once again, midday stem water potentials were maintained near target levels throughout the 2004 season. All three deficit treatments led to significantly lower yields in the third year of treatment imposition. However, if yields per unit light intercepted was calculated, all three deficit treatments had significantly higher yields than the control. This suggests that if deficit irrigated trees had been planted closer together, they might have had higher overall yields compared to the control. Incidence of kernel mold has continued to be less in deficit irrigated trees. Significant changes in leaf specific area (a measure of spur quality), particularly in inner canopy positions in the deficit treatments, may lead to improved spur longevity and shifts in canopy nut production patterns in the coming season. Objective 3- The emphasis for this work has shifted somewhat and preliminary work is now being done in studying role of water stress in seasonal variations in plant protective compounds in walnut as well as interactions with mold.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers desire.

Publications

• Olson, Bill. Bruce Lampinen, Samuel Metcalf, Jed Walton, and Sean Miller. Comparisons between mechanical hedging treatments and the non-hedged check- 2003. Walnut Research Reports 2003. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp.171-179.

Progress 01/01/03 to 12/31/03

Outputs
Objective 1- The technique of making selective thinning cuts high in the canopy has again been shown to have no significant effects on midday canopy light interception on any individual day during the season in 2003. However, when the average seasonal canopy light interception was calculated, there was a small but significant increase for the high limb pruning treatment in 2002 and in 2003. Shoot growth data suggests that when large thinning cuts were made high in the canopy, energy was reallocated into shoot growth on the sides of the canopy. In general, yields appeared to be directly related to the midday canopy light interception with increased light interception resulting in increased yields. The third year data again showed no significant impact of the pruning treatment on yield and a slight but significant increase in seasonal average canopy light interception in the Tulare trees on Northern California Black rootstock. The results suggest that use of selective pruning cuts high in the canopy can be effectively used to maintain high density Tulare walnut plantings at a reduced height without significant impacts on yield. Objective 2- This project was initiated to investigate the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Monitoring will be carried out for 6 years to quantify the impacts of treatments on spur longevity. In 2003, all three deficit treatments had significantly lower midday canopy light interception than the control throughout the season. Once again, midday stem water potentials were maintained near target levels throughout the 2003 season. All three deficit treatments led to significantly lower yields in the third year of treatment imposition, but this is partially due to decreased canopy area since treatments were imposed before trees had filled in their allotted space. Incidence of kernel mold has been less in deficit irrigated trees. Significant changes in leaf specific area (a measure of spur quality), particularly in inner canopy positions in the deficit treatments, may lead to improved spur longevity and shifts in canopy nut production patterns in the coming season. Objective 3- As the key insect pest of walnut, codling moth requires extensive intervention to prevent unacceptable levels of nut damage by harvest. This work was initiated to look at the relationship between tree water status and nut susceptibility to provide growers with an opportunity to maximize the natural resistance of nuts to codling moth damage through irrigation management. Results of this work suggest that codling moth susceptibility in walnut is directly related to water status with trees receiving the most water being the most susceptible to codling moth attack. This work suggests that some level of deficit irrigation may help to relive codling moth pressure in walnut.

Impacts
Deficit water management combined with selective pruning has been shown to have applicability in managing dense plantings, if trees have filled in allotted space when deficits are imposed. In addition to providing canopy management benefits, deficit irrigation management may make the orchards less susceptible to insect and/or fungal pests. By minimizing irrigation events, pruning tower use and spraying operations, reliance on fossil fuels can be decreased while minimizing pesticide usage. Employing these techniques would provide direct benefits to growers by decreasing costs of production and reducing potential for worker and environmental pesticide exposure while producing products with the lower pesticide residues consumers desire.

Publications

• Lampinen, B., DeJong, T., Weinbaum, S., and Metcalf, S. 2001. Spur dynamics and almond productivity. 2001 Almond Industry Conference Proceedings, Dec. 5-6, 2001, Modesto, CA. pp. 127-133.
• Lampinen, B., DeJong, T., Weinbaum, S. and Metcalf, S. 2002. Spur dynamics and almond productivity. 2002 Almond Industry Conference Proceedings, Dec. 5-6, 2002, Modesto, CA. pp. 54-62.
• Lampinen, B., DeJong, T., Weinbaum, S., and Metcalf, S. 2002. Spur dynamics and almond productivity. 2003 Almond Industry Conference Proceedings, Dec. 3-4, 2003, Modesto, CA. pp. 57-69.
• Mills, N.J., Lampinen, B.D., Julier, E., and Grant, J. 2001. Managing codling moth in walnuts: Parasitism and nut susceptibility. Walnut Research Reports 2001. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 363-376.
• Lampinen, B. D. and Metcalf, S. 2001. Comparisons of Watermark sensors with stem water potential reading in 'Chandler', 'Howard' and 'Tulare' walnut orchards. Walnut Research Reports 2001. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 165-173.
• Lampinen, B.D., Reil, W., Ramos, D., and Metcalf, S. 2001. Hand thinning in conjuction with mechanical pruning to open canopy in 'Tulare' walnuts. Walnut Research Reports 2001. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 185-191.
• Lampinen, B., Reil, W., Ramos, D., and Metcalf, S. 2001. Responses of 'Howard' and 'Tulare' walnuts on two roostocks at two planting densities to irrigation cycles. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 161-169
• Lampinen, B., Buchner, R., Fulton, A., Grant, J., Mills, N., Prichard, T., Schwankl, L., Shackel, K., Gilles, C., Little, C., Metcalf, S., and Rivers, D. 2002. Irrigation management in walnut using evapotranspiration and plant based data. Walnut Research Reports 2002. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 145-159.
• Lampinen, B., Metcalf, S., Reil, W. and Ramos, D. 2003. High limb pruning to manage densely planted 'Tulare' walnuts. HortScience 38(5):657.

Progress 01/01/02 to 12/31/02

Outputs
Objective 1- There were again no significant effects of the high limb pruning treatment on midday canopy light interception on any individual day during the season in 2002. However, when the average seasonal canopy light interception was calculated, there was a small but significant increase for the high limb pruning treatment in 2002. This suggests that the pruning treatments may have stimulated a slight increase in canopy development, perhaps due to a slight decrease in crop load in the high limb pruning treatment in 2002. The appearance of the high limb pruned trees is substantially different than that of the trees that have not been pruned after two years of treatment imposition. The overall canopy height is considerably lower and the average height at which the nut crop is borne appears to have moved down about 6-10 feet in the high limb pruned trees. This suggests that high limb pruning in this manner may be useful for canopy management in high density Tulare plantings as they mature. There were no significant treatment effects on yield. First year results were encouraging in that yields were not negatively impacted by the high limb pruning treatment. The plan is to continue the pruning treatments for the 3 years it is anticipated will be required to lower canopy height without impacting yield. Objective 2- The objectives of this aspect of the project are to quantify the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Tags were placed on 2400 spurs which will be monitored throughout the anticipated 6 years of the study to quantify the impacts of treatments on spur longevity. In 2002, all three deficit treatments had significantly lower midday canopy light interception than the control throughout the season. Unlike in 2001, stem water potentials were able to be maintained at target levels throughout the 2002 season. All three deficit treatments had a negative impact on yield but the low water, high nitrogen treatment did not yield significantly less per unit canopy light interception. Improvements in spur quality as measured by leaf specific area occurred in inner canopy locations in the deficit treatment suggesting potential future differences in flowering and nut retention is possible in these locations. Objective 3- Codling moth is the key pest in walnut orchards and requires successive intervention through the season to suppress damage levels at harvest. This work was initiated to look at the relationship between leaf water potential and nut susceptibility to provide growers with an opportunity to maximize the natural resistance of nuts to codling moth damage through irrigation management. The work was overlaid on another walnut irrigation project that was initiated this year but due to an untimely grower spray just before the desired sampling date at one of two locations, data was only collected at one site. Preliminary results indicate that codling moth susceptibility was again lower on nuts from deficit irrigated trees.

Impacts
The results of this project are promising. If deficit water management can be used as a tool for managing dense plantings while decreasing the susceptibility of these orchards to pests, the reliance on fossil fuels for orchard practices such as irrigating, pruning tower operation and spraying operations can be reduced as could pesticide usage. These practices would provide benefits to growers (decreased costs of production and reduced pesticide exposure) and to consumers (products with the lower pesticide residues they desire).

Publications

• Lampinen, B.D., W. Reil, D. Ramos and S. Metcalf. 2001. Effects of summer pruning on Tulare walnut canopy light interception and yields. Walnut Research Reports 2001. Walnut Marketing Board, 1540 River Park Drive #203, Sacramento, CA 95815. pp. 193-194

Progress 01/01/01 to 12/31/01

Outputs
Objective 1- There were no significant effects of the high limb pruning treatment on midday canopy light interception at any time during the season. The largest factor affecting the canopy light interception was the date of hedging. Trees spaced at 15.3 feet tended to have higher water potentials than trees spaced at 11.5 feet and this might explain a tendency toward higher canopy light interception and higher yields with the wider spaced trees. There were no significant treatment effects on yield. First year results were encouraging in that yields were not negatively impacted by the high limb pruning treatment. The plan is to continue the pruning treatments for the 3 years it is anticipated will be required to lower canopy height without impacting yield. Objective 2- The objectives of this aspect of the project are to quantify the dynamics of spur renewal, fruitfulness and longevity and to determine how these are influenced by nitrogen and irrigation. Tags were placed on 2400 spurs which will be monitored throughout the anticipated 6 years of the study to quantify the impacts of treatments on spur longevity. After late July, the two moderate irrigation treatments led to a significant decrease in canopy light interception. This is most likely because the midday stem water potentials in these treatments were consistently below -1.2 MPa which is the level at which vegetative growth is impacted. There did not appear to be any treatment impacts on yield in the Nonpareil with the treatments all yielding within 75 pounds per acre of the control. Nut size was significantly smaller on both the moderate nitrogen and moderate irrigation treatments. In order to get smaller nut size and equivalent yields, there must have been more nuts maintained on these trees in the year of treatment imposition. This suggests that differences in canopy light penetration may have influenced nut retention. Objective 3- Codling moth is the key pest in walnut orchards and requires successive intervention through the season to suppress damage levels at harvest. This work was initiated to look at the relationship between leaf water potential and nut susceptibility to provide growers with an opportunity to maximize the natural resistance of nuts to codling moth damage through irrigation management. The experiments were conducted in two unsprayed commercial orchards. Irrigation treatments were imposed by changing/and blocking sprinkler heads. Nuts were sampled at five times during the season and used for in laboratory codling moth susceptibility assays. In general, after treatment differences in water potential were seen, the susceptibility of the nuts to codling moth attack varied as well with lower water status correlating with decreased codling moth susceptibility. Since both of the orchards were moderately to severely stressed, we did not have fully watered controls. Natural codling moth damage in both orchards was very light, particularly for unsprayed orchards.

Impacts
Developing pruning methods that maintain productivity in high density plantings will help lead to improved productivity with decreased inputs. The first year results of this project are promising. If deficit water management can be used as a tool for managing these dense plantings while decreasing the susceptibility of these orchards to pests, the reliance on fossil fuels for orchard practices such as irrigating, pruning tower operation and spraying operations can be reduced. In addition, the use of chemical pesticides can be minimized leading to reduced potential for environmental impacts. These practices would provide benefits to growers (decreased costs of production and reduced pesticide exposure) and to consumers (products with the lower pesticide residues they desire).

Publications

• No publications reported this period