Source: KANSAS STATE UNIV submitted to NRP
EFFECTS OF ORGANIC FERTILITY MANAGEMENT ON CROP HEALTH AND PHYTOCHEMICAL CONTENT OF VEGETABLES UNDER OPEN FIELD AND HIGH TUNNEL PRODUCTION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
0210178
Grant No.
2007-51300-03790
Cumulative Award Amt.
(N/A)
Proposal No.
2007-01398
Multistate No.
(N/A)
Project Start Date
Jun 1, 2007
Project End Date
May 31, 2012
Grant Year
2007
Program Code
[113]- Integrated Organic Program
Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
HORTICULTURE & FORESTRY
Non Technical Summary
The goal of this multidisciplinary project is to improve our understanding of the influence of organic fertilizer sources on crop health, including pest and disease resistance, yield, and quality of vegetable crops. Specifically, we will compare low and high rates of selected organic fertilizer sources and contrast them to equivalent rates of conventional fertilizers in replicated, long-term field and high tunnel (unheated greenhouse) plots. The effect of these four contrasting systems will be measured on plant and soil nutrient status and soil quality attributes. Insect and disease presence and abundance on plants will be assessed. We will also evaluate whether there is an influence on phytonutrient and phytochemical levels (β-carotene, folic acid, vitamin C, vitamin E, individual and total phenolics, and antioxidant levels) and whether these, in turn, affect pest and disease incidence. Crops evaluated will include tomato and pac choi. Tomato is economically important, and pac choi, an important Asian vegetable, has proven to be a valuable model crop in our preliminary studies, due to its responsiveness to fertility, susceptibility to insect attack, and phytochemical response. This three-year effort will emphasize regionally available organic fertility options in experiment station and farm-based studies to produce results with specific regional application, but with broader relevance to global organic production.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
20514601060100%
Knowledge Area
205 - Plant Management Systems;

Subject Of Investigation
1460 - Tomato;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
1. Determine the levels of selected phytochemicals in tomato and pac choi grown with organic and conventional fertilizers at low and high N application rates. 2. Assess the activation of key genes involved in the biosynthesis of phytochemicals in tomato and pac choi as a potential technique for rapid evaluation of crop response to organic fertility treatments. 3. Measure soil fertility and quality and plant nutrient status in relation to tomato and pac choi production at high and low rates of N-fertilization in open field and high tunnel production systems. 4. Use field and greenhouse studies to measure the effects of organic N-fertilization and high tunnel production environments on insect and disease pressure in tomato and pac choi. 5. Determine the relationship between phytochemical content (in response to organic N-fertilization) and disease and insect pest reaction. 6. Develop fact sheets, websites, workshops, and other outreach information and evaluate impact using pre- and post-tests. Integrate the outreach information into new courses at KSU and develop formats available for distance-education.
Project Methods
Overview of field site, Replicated trials will be conducted at the KSU Research and Extension Center, Olathe. At this site, 3 organic high tunnels (20ft x 32ft Stuppy Polar Cold Frames, with single layer poly and 5ft rollup sides) and 3 conventional tunnels were established in a paired replicated arrangement in 2002, to allow statistically valid comparisons between organic and conventional systems. Adjacent replicated organic and conventional field plots provide additional environments and permit comparisons between high tunnel and open field conditions. Experimental approach. Soil fertility treatments chosen during the course of trials conducted under this project will be determined by the project team and advisory group, and will be selected based on N availability from mineralization study results, total N content, local availability, cost and other factors, so that the organic fertility treatments represent actual on-farm practices typical of the Great Plains. Soil fertility treatments in the form of composts will be chosen that meet requirements of the National Organics Standards Board for soil fertility and crop nutrient management. Fertility applications will be consistent across all treatment replications and carefully quantified. High fertility levels for organic treatments will be based on soil analyses, and will start from the reference point of our current practice, which is to apply compost at double the conventional N fertilizer requirement for conventionally grown vegetable crops in Kansas. Low fertility levels will be established by applying N at sub optimal rates in organic and conventional plots, with rates to be determined based on soil tests, but aiming to supply one half the required N for the crop. High N plots will likely receive split applications, with shallow pre-plant incorporation of compost followed by fertigation with water soluble fertilizer (e.g., fish emulsion). Low N plots would receive only pre-plant fertility treatments. Inorganic fertilizer salts that are immediately soluble will be applied to the inorganic fertilizer plots. Application rates of other nutrients (P, K, etc.) will be matched between conventional and organic treatments to the extent possible, but the intention of our treatment selection is to represent actual on farm practices. Therefore, effects of any differences in application rates of nutrients besides N, such as micronutrients that are applied via fish emulsion in the organic treatment but not in the inorganic treatment, will be assessed with the plant tissue and soil analyses. Differences between conventional and organic treatments can be correlated to yield and other responses with multivariate statistical analyses. The influences of N-sources at low and high rates on crop phytochemistry, and on disease and pest incidence and reaction will be examined on selected vegetable crops, particularly tomato and pac choi.

Progress 06/01/07 to 05/31/12

Outputs
OUTPUTS: The four-year study examines the health-promoting qualities of pac-choi and tomato in relation to their phytochemicals as influenced by cultural and management practices such various fertility levels in high tunnel and open field conditions under organic and conventional managements during 2008-2012. Typically two crops of pac-choi, cv. Mei Qing Choi (spring and fall) and one summer crop of tomato, cv. Bush Celebrity were grown each year at the K-State Horticulture Research and Extension Center, Olathe, KS. However during 2010 (fourth year of the field trial) only tomato crop was evaluated for the phytochemical content. Open field and high tunnel fields were set up adjacent to each other, each containing organic and conventional plots (9.8 x 6.1 m) receiving either conventional or organic management practices. Each plot was further divided into 3 subplots, each of which received 3 levels of fertility, namely; no fertilizers (control), a basal application of fertilizer or compost (low fertility) and basal doze plus additional fertilization through fertigation with either synthetic fertilizers or fish hydrolyzate (high fertility). The field trial was conducted using a latin square design with 3 replications. Plots were fertilized with basal dose before planting and organic plots were fertilized with Hu More compost. Seedlings were grown in a greenhouse for 4 weeks and transplanted to the field and were drip-irrigated as needed. The two crops were rotated in each plot with fall cover crop (rye) and buckwheat planted between spring and fall pac-choi crops. However, during 2010, only summer tomato crop was grown. The incidence of pests was monitored and pesticide application was not warranted during 2010 crop season. During 2011-2012, phytochemical analyses from field samples and data analyses, interpretation and coordination were accomplished. Soil analyses for available nitrogen (nitrate and ammonium forms) before planting and tissue analyses for nitrate nitrogen at various stages of crop growth were performed to determine the effects of fertility management practices and production environments on crop quality, performance and yield. Crop quality was also evaluated by determining the total phenolic content including the levels of several key phenolic compounds and the antioxidant capacity in pac-choi and tomato fruits at various stages of crop growth. In addition, complementary greenhouse and field studies were conducted to determine the impact of fertility levels and management practices on the phytochemical content and pest incidence in pac-choi. The results were shared with growers, grower groups, extension personnel and other stakeholders. Outreach activities included presentations made at grower conferences, seminars at universities and presentations at the annual conference of the American Society for Horticultural Science. PARTICIPANTS: In addition to the PIs and Co-PIs following graduate students contributed to this project. Rojee Pradhan, M. S. student involved in phytochemical and crop quality aspects. Myung-Min Oh, Ph.D. student involved in phytochemical and crop quality aspects. May Altamimi, M.S. student involved in soil and tissue analyses. Martin Talavera, Ph.D. student involved in sensory and crop quality analyses. Wendy Johnson, Ph.D. student involved in phytochemical- pest interactions. TARGET AUDIENCES: The target audience includes many segments of our society including professionals involved in academic endeavors, and food and agriculture-related industry, growers, consumers and other stakeholders. PROJECT MODIFICATIONS: The only modifications were two no-cost time extensions of this project until 5/1/2012 with a change of principal investigators to C. B. Rajashekar and Rhonda Janke.

Impacts
The project examines the effects of cultural and management practices on the quality of pac-choi and tomato with regard to their health-promoting phytochemiclas. The results of this study are expected to provide useful information to growers on the best management practices in relation to fertility management and production practices to improve the health-promoting qualities of pac choi and tomato. The consistent results from the three years of field trial was that both crops grown in open field had higher total phenolic content and antioxidant capacity than did those grown in high tunnels. Spring pac-choi was generally richer in phytochemical content than fall crop. This trend was true regardless of the management conditions and fertility levels. However, there were no significant differences in phytochemical content between management conditions and fertility levels in fall pac-choi. In spring crop of pac-choi the levels of ferulic acid, caffeic acid and sinapic acid were higher when grown in open field than in high tunnels. Also, higher fertility both in organic and conventional plots tend to lower the accumulation of several phenolic compounds including sinapic acid, caffeic acid and ferulic acid. However, there were no significant difference in phytochemicals between pac-choi grown under organic and conventional managements. In tomatoes, the accumulation of rutin, chlorogenic acid and ferulic acid was higher in crops grown in open field than in high tunnels. Higher fertility tend to lower the accumulation of some phenolic compounds in tomato crop both in organically and conventionally managed plots. The results were variable from year to year. There were no overall significant differences in phytochemical content between tomatoes grown under organic and conventional management. The phenolic content of tomato fruit depend on its stage of maturity. Typically unripe fruits had very little of phenolic compounds but accumulate as they mature and ripen. Fully ripe or partially ripe fruits had the highest amount of phenolic compounds including ruitn, caffeic acid, ferulic acid, chlorogenic acid and myricetin. This trend was consistent regardless of growing conditions and crop management practices and fertility levels. The consistent observation that open field improves the phytochemical content in these crops suggests that high light intensity and even UV-B, which is a part of the solar radiation, may have a positive impact on the health-promoting qualities of these vegetables. However, it should be noted that the biomass accumulation and yield were significantly lower in crops grown in open field than those grown in high tunnels. With regard to fertility, soil N levels were affected by management practices, fertility source and rates. Low levels of N produced higher total phenoilc content with significant increase accumulation of specific phenolic compounds in tomatoes. The results suggest that growing tomatoes and pac-choi in open field with low N- fertility may improve the health-promoting qualities but with lower yield compared to high tunnel production environment.

Publications

  • M. M. Oh, E. E. Carey, C. B. Rajashekar, 2011, Antioxidant phytochemical in lettuce grown in high tunnels and open field, Hort. Environ. Biotechnol. 52: 133-139
  • M. M. Oh, R. Janke, E. E. Carey and C. B. Rajashekar, 2011, Effects of growing conditions and fertility levels on the health-promoting phytochemicals in tomato and pac-choi, Annual meeting of the American Society for Horticultural Science, 2011


Progress 06/01/10 to 05/31/11

Outputs
OUTPUTS: The study examines the health-promoting qualities of pac-choi and tomato in relation to their phytochemicals as influenced by cultural and management practices such various fertility levels in high tunnel and open field conditions under organic and conventional managements. Typically two crops of pac-choi, cv. Mei Qing Choi (spring and fall) and one summer crop of tomato, cv. Bush Celebrity were grown each year at the K-State Horticulture Research and Extension Center, Olathe, KS. However during the current year (fourth year of the field trial) only tomato crop was evaluated for the phytochemical content. Open field and high tunnel fields were set up adjacent to each other, each containing organic and conventional plots (9.8 x 6.1 m) receiving either conventional or organic management practices. Each plot was further divided into 3 subplots, each of which received 3 levels of fertility, namely; no fertilizers (control), a basal application of fertilizer or compost (low fertility) and basal doze plus additional fertilization through fertigation with either synthetic fertilizers or fish hydrolyzate (high fertility). The field trial was conducted using a latin square design with 3 replications. Plots were fertilized with basal dose before planting and organic plots were fertilized with Hu More compost. Seedlings were grown in a greenhouse for 4 weeks and transplanted to the field and were drip-irrigated as needed. The two crops were rotated in each plot with fall cover crop (rye) and buckwheat planted between spring and fall pac-choi crops. However, during 2010, only summer tomato crop was grown. The incidence of pests was monitored and pesticide application was not warranted during 2010 crop season. Soil analyses for available nitrogen (nitrate and ammonium forms) before planting and tissue analyses for nitrate nitrogen at various stages of crop growth were performed to determine the effects of fertility management practices and production environments on crop quality, performance and yield. Crop quality was also evaluated by determining the total phenolic content including the levels of several key phenolic compounds and the antioxidant capacity in pac-choi and tomato fruits at various stages of crop growth. In addition, complementary greenhouse and field studies were conducted to determine the impact of fertility levels and management practices on the phytochemical content and pest incidence in pac choi. The results were shared with growers, grower groups, extension personnel and other stakeholders. Outreach activities included presentations made at grower conferences, seminars at universities and presentations at the annual conference of the American Society for Horticultural Science. PARTICIPANTS: In addition to the PIs and Co-PIs following graduate students contributed to this project. Rojee Pradhan, M. S. student involved in phytochemical and crop quality aspects. Myung-Min Oh, Ph.D. student involved in phytochemical and crop quality aspects. May Altamimi, M.S. student involved in soil and tissue analyses. Martin Talavera, Ph.D. student involved in sensory and crop quality analyses. Wendy Johnson, Ph.D. student involved in phytochemical- pest interactions. TARGET AUDIENCES: The target audience includes many segments of our society including professionals involved in academic endeavors, and food and agriculture-related industry, growers, consumers and other stakeholders. PROJECT MODIFICATIONS: The only modifications were two no-cost time extensions of this project until 5/1/2012 with a change of principal investigators to C. B. Rajashekar and Rhonda Janke.

Impacts
The study addresses the impact of cultural and management practices on the quality of pac-choi and tomato with regard to their health-promoting phytochemiclas. The results of this study are expected to provide useful information to growers on the best management practices in relation to fertility management and production practices to improve the health-promoting qualities of pac choi and tomato. The consistent results from the three years of field trial was that both crops grown in open field had higher total phenolic content and antioxidant capacity than did those grown in high tunnels. This trend was true regardless of the management conditions and fertility levels. During the 2010 growing season, significant increase in chlorogenic acid, p-coumaric acid and rutin were observed in tomato fruits from crops grown in open field compared to those grown in high tunnels. The rutin content in the fruits from open field was approximately four-times higher than those grown in high tunnels. The ruitn accumulation in tomato increased during fruit ripening while other phenolic compounds including ferulic acid decreased. However, some phenolic compounds including caffeic acid and p-coumaric acid were found only in the ripened fruits but not in green fruits suggesting that the stage of fruit ripening has a significant effect on the composition and the content of phytochemicals. The consistent observation that open field improves the phytochemical content in these crops suggests that high light intensity and even UV-B, which is a part of the solar radiation, may have a positive impact on the health-promoting qualities of these vegetables. However, it should be noted that the biomass accumulation and yield were significantly lower in crops grown in open field than those grown in high tunnels. The overall response of phytochemicals to organic management was variable in tomatoes and a clear trend was not apparent. This is consistent with observations from previous years and with observations on pac-choi. With regard to fertility, soil N levels were affected by management practices, fertility source and rates. Low levels of N produced higher total phenoilc content with significant increase accumulation of specific phenolic compounds in tomatoes. Although this was clear in open field, the results were somewhat variable in high tunnels and with organic management. The results suggest that growing tomatoes in open field with low N- fertility may improve the health-promoting qualities but with lower yield compared to high tunnel production environment.

Publications

  • M. M. Oh, E. E. Carey, C. B. Rajashekar, 2011, Antioxidant phytochemical in lettuce grown in high tunnels and open field, Hort. Environ. Biotechnol. DOI 10.1007/s00277-009-0780-0.
  • M. M. Altamimi, Myung-Min Oh, R. R. Janke, K. A. Williams, N. O. Nelson, C. B. Rajashekar, D. Rotenberg, E. E. Carey, 2009, Organic versus conventional fertilization of pac choi and tomato produced in field versus high tunnels influences crop yield, soil and plant quality, HortSci. 44: 1112.
  • M. M. Oh, H. N. Trick, and C. B. Rajashekar, 2008, Secondary metabolism and antioxidants are involved in environmental adaptation and stress tolerance in lettuce, J. Plant Physiol. 166: 180-191
  • M. M. Oh,, E. E. Carey, and C. B. Rajashekar, 2009, Environmental stresses induce health-promoting phytochemicals in lettuce, Plant Physiol. Biochem. 47: 578-583
  • M. M. Oh and C. B. Rajashekar, 2009, Antioxidant content of edible sprouts: effects of environmental shocks, J. Sci. Food Agric. 89: 2221-2227
  • C. B. Rajashekar, E. E. Carey, X. Zhao and M.M Oh, 2009, Health-promoting phytochemicals in fruits and vegetables: Impact of abiotic stresses and crop production practices, Functional Plant Sci. Biotech. 3: 30-38


Progress 06/01/09 to 05/31/10

Outputs
OUTPUTS: The ongoing-project involving two crops of pac-choi (spring and fall) and a summer tomato crop continued for the third year during 2009. The planning for the various activities scheduled for 2009 began early in February, 2009 and the research team made up of graduate students and their advisers and the supporting technicians and crew met once a month to share information, plan activities, revise the plan of action, if warranted based on past years' experience, and review progress of the project during 2009. In a four-year field trail at the K-State Horticulture Research and Extension Center, Olathe, pac choi and tomato are being evaluated for their health-promoting qualities under organic and conventional management practices in open field and high tunnels. At this site, plots of open field and high tunnels were set up adjacent each other. Each plot (9.8 x 6.1 m) receiving either conventional or organic management practices was divided into 3 subplots. The fertility treatments were assigned to subplots at three levels; control- no fertilizer, medium fertility- a basal application of either compost or synthetic fertilizer, and high fertility- basal dose plus fertigation with fish hydrolyzate or synthetic fertilizer. The fertilization rates were based on the soil tests. Organic plots were fertilized with Hu-More compost before transplanting. The fertility levels were assigned using a latin square design with 3 replications. Pac choi (cv. Mei Qing Choi) and tomato (cv. Bush Celebrity) were transplanted into the plots and were drip irrigated as needed Two crops of pac choi and one crop of tomato were grown during the year. The experimental design included crop rotations, with tomato and pac choi rotating to opposite sides of the plot each year, as well as cover crops (rye) and with buckwheat sown between spring and fall pac choi plantings. The pest incidence was monitored through out the growing season and was controlled using organically approved pesticides. Soil analyses for available nitrogen (nitrate and ammonium forms) and tissue analyses for nitrate nitrogen at various stages of crop growth were performed to determine the effects of fertility management practices and production environments on crop quality, performance and yield. Crop quality was evaluated by determining the total phenolic content including the levels of several key phenolic compounds and the antioxidant capacity in pac-choi and tomato fruits at various stages of crop growth. In addition, complementary greenhouse and field studies were conducted to determine the impact of fertility levels and management practices on the phytochemical content and pest incidence in pac choi. Outreach activities included presentations made at grower conferences, seminars at universities and a presentation at the annual conference of the American Society for Horticultural Science. PARTICIPANTS: In addition to the PIs and Co-PIs following graduate students contributed to this project. Myung-Min Oh, Ph.D. student involved in phytochemical and crop quality aspects. May Altamimi, M.S. student involved in soil and tissue analyses. Martin Talavera, Ph.D. student involved in sensory and crop quality analyses. Wendy Johnson, Ph.D. student involved in phytochemical-pest interactions. TARGET AUDIENCES: The target audience includes many segments of our society including professionals involved in academic endeavors, and food and agriculture-related industry, growers, and consumers. PROJECT MODIFICATIONS: The only modification was a no-cost time extension of this project until 5/1/2011 with a change of principal investigators to C. B. Rajashekar and Rhonda Janke.

Impacts
The results of this study are expected to provide useful information to growers on the best management practices in relation to fertility management and production practices to improve the health-promoting qualities of pac choi and tomato. Our preliminary results show that crops grown in open field had higher total phenolic content and antioxidant capacity in both pac-choi and tomato compared to those grown in high tunnels. In addition, significant increase in chlorogenic and caffeic acids in pac choi and chlorogeic acid and rutin in tomato fruits were observed in crops grown in open field. The improved phytochemical content in these crops grown in open field appears to be due to higher light intensity in open field relative to high tunnels. However, the biomass accumulation and yield were significantly lower in crops grown in open field than in high tunnels. The overall response of phytochemicals to organic management was variable in both pac choi and tomato and a clear trend was not apparent. This is consistent with observations from previous years. With regard to fertility, soil N levels were affected by management practices, fertility source and rates. Low levels of N produced higher total phenolic content with significant increase accumulation of specific phenolic compounds in pac choi and tomato. In summary, the results suggest that growing pac choi and tomato crops in open field and with low fertility (N) has a beneficial effect in improving their quality in relation to their health-promoting phytochemicals.

Publications

  • Altamimi, M.M., Oh, M.M., Janke, R.R., Williams, K.A., Nelson, N.O., Rajashekar, C.B., Rotenberg, D., and Carey, E.E. 2009, Organic versus conventional fertilization of pac choi and tomato produced in field versus high tunnels influences crop yield, soil and plant quality, HortSci. 44: 1112.
  • Oh, M. M, Trick, H.N. and Rajashekar, C.B. 2008, Secondary metabolism and antioxidants are involved in environmental adaptation and stress tolerance in lettuce, J. Plant Physiol. 166: 180-191
  • Oh, M.M., Carey, E.E. and Rajashekar, C.B. 2009, Environmental stresses induce health-promoting phytochemicals in lettuce, Plant Physiol. Biochem. 47: 578-583
  • Oh, M.M. and Rajashekar, C.B. 2009, Antioxidant content of edible sprouts: effects of environmental shocks, J. Sci. Food Agric. 89: 2221-2227
  • Rajashekar, C.B., Carey, E.E., Zhao, X. and Oh, M.M. 2009, Health-promoting phytochemicals in fruits and vegetables: Impact of abiotic stresses and crop production practices, Functional Plant Sci. Biotech. 3: 30-38


Progress 06/01/08 to 05/31/09

Outputs
OUTPUTS: Activities during the second year of our project were conducted during parts of the 2008 and 2009 cropping seasons. Activities were planned, and progress reviewed during monthly team meetings, involving all team members including graduate students, and we held a meeting in August of 2008 with our grower steering committee to review results and visit field plots. Teams made up of graduate students and their advisors planned and conducted activities in specific focus areas - plant and soil nutrition; phytochemical analysis; crop health; and sensory analysis. The primary trial site was in the field at the K-State Horticulture Research and Extension Center, Olathe, where pac choi and tomato were evaluated under organic and conventional fertility regimes in the open field and under high tunnels at a trial site established in 2002. At this site, open field plots are in a block adjacent to high tunnel plots, and within these blocks, pairs of plots are managed organically or conventionally. High tunnel and open field plots are 9.8 x 6.1 m, and high tunnels have 1.5 m rollup sidewalls. Within each plot, three fertility levels were established in subplots 3.2m x 6.1m: no fertilizer (control), medium fertility (compost or synthetic fertilizer) and high fertility (compost or synthetic fertilizer, plus fertigation with fish hydrolyzate or synthetic fertilizer). These fertility levels were assigned using a latin square design to control for possible position effects in high tunnel plots. Within each plot, pac choi (cv. Mei Qing Choi) and tomato (cv. Bush Celebrity) were planted in strips occupying one-half of the plot and covering each of the soil fertility treatments. Two crops (spring and fall) of pac choi were grown during the year and one crop of tomato (summer). The experimental design included crop rotations, with tomato and pac choi rotating to opposite sides of the plot each year, as well as cover crops, with plots sown to rye in the winter, and with buckwheat sown between spring and fall pac choi plantings. To avoid confounding of pest attack and fertility effects on crop phytochemical content, pest incidence was monitored and controlled using organically approved pesticides. Tomato diseases were monitored but not controlled, and were a problem, particularly in field plots. Soils and crops were sampled during growth with particular attention to nitrate, phenolic and antioxidant contents, and yield and quality monitored to determine effects of organic fertility management on crop health and phytochemical content. Complementary greenhouse trials were conducted to evaluate effects of organic fertility management on pac choi. In 2008, separate field trials evaluated efficacy of organic pesticides for control of pests of tomato and pac choi. In 2009, controlled greenhouse and field studies evaluated effects of fertility and pest incidence on crop health. Outreach activities included presentations made at grower conferences, seminars presented at universities and a poster presentation at the annual conference of the American Society for Horticultural Science. Many visitors saw and heard about our trials. PARTICIPANTS: Dorith Rotenberg assisted with statistical analysis and integration of data sets produced by the nutrition, plant health, phytochemical and sensory analysis teams. Myung-Min Oh, Ph.D. student under the project, defended his thesis. May Altamimi, M.S. student under the project, defended her thesis. Martin Talavera, Ph.D. student under the project, defended his thesis. Other project partners contributed in an ongoing fashion to project activities through supervision of graduate students, and participation in project meetings. TARGET AUDIENCES: Academic, producer and consumer audiences have been interested in research approaches and results obtained from experiments conducted under this project, and are eager to receive take-home messages from this research PROJECT MODIFICATIONS: The only modifications which have occurred under the project were the addition of a component of research - sensory analysis - at no extra charge to the project.

Impacts
Since experiments have not yet been concluded, it is too early to reach conclusions about changes in knowledge that have occurred with respect to our research objectives. Our experimental set-up, with its comparable nutrient levels in organic and conventional systems, should allow us to gain valuable insights into the effects of soil fertility on crop health and nutritional quality, and to evaluate the hypothesis that organic crops are higher in phytochemicals than conventional crops due to limitations of nitrogen in organic systems. The team effort to design and implement a rather complex research project contributed to an appreciation for the challenges and opportunities of interdisciplinary research, and provided graduate students with valuable lessons in teamwork. Four graduate students worked under the project during the reporting period with one completing an M.S. thesis and two completing and defending Ph.D. theses, demonstrating requisite high levels of analytical capabilities and competence.

Publications

  • Oh, M.M., Carey, E.E., and Rajashekar, C.B. 2009. Environmental stresses induce health-promoting phytochemicals in lettuce. Plant Physiology and Biochemistry 47:578-583.
  • Oh, M.M., Trick, H., Carey, E., Rajashekar, C. 2008. Secondary metabolites and antioxidants in relation to plant adaptation and stress tolerance in lettuce. HortScience 43:1277.
  • Altamimi, M., Oh, M.M., Janke, R.R., Williams, K.A., Nelson, N.O., Rajashekar, C.B., Rotenberg, D., Carey, E.E. 2009. Organic versus conventional fertilization of pac choi and tomato produced in the field versus high tunnels influences crop yield, plant and soil nitrogen and phytochemical content, HortSci. 44: 1112.
  • Altamimi, M., Janke, R.R., Williams, K.A. 2009. Sufficiency ranges for nitrate in leaf petiole sap of greenhouse pac choi produced with organic versus inorganic fertilizers. HortSci. 44, 1024.
  • Oh M.M., 2008. Plant Adaptation and Enhancing Phytochemicals in Lettuce Through Environmental Stresses. Ph. D. Thesis, Kansas State University, Manhattan, KS, pp 175.
  • Talavera Bianchi, M.J. 2009. Sensory analysis of pac choi and tomato grown under organic and conventional systems. Ph.D. Thesis, Kansas State University, Manhattan, KS.


Progress 06/01/07 to 05/31/08

Outputs
OUTPUTS: During this initial partial project reporting period activities have been completed related to the goals and objectives of the project. Project partners have met intensively, graduate students and technicians have been recruited, and initial trials have been conducted at the Olathe trial site. Insect and diseases have been monitored, crop fertilizer effects assessed through tissue analysis and yield measurement. These preliminary trials and other activities, including consultation with the project steering committee, have helped set the stage for what we hope will be a productive year of the work in 2008. PARTICIPANTS: Steering Committee partners, including Kansas Rural Center, Kansas City Center for Urban Agriculture, and organic farmers Bob Lominska, Stu Shafer, and Robins Hail and Jim Wood TARGET AUDIENCES: Organic and conventional fruit and vegetable farmers, the broader communities of researchers and consumers interested in health-promoting aspects of organic food. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Oh, M-M., E. Carey and C. Rajashekar. 2007. Environmental stresses induce health-promoting phytochemicals in lettuce. HortScience 42:993. This was an oral presentation by Myung-Min Oh, on the results of preliminary studies conducted in the growth chamber.

Publications

  • No publications reported this period