Progress 10/01/00 to 09/30/05
Outputs
This project has demonstrated the financial and ecological compatibility of mixed production systems where trees and/or woody shrubs are combined with traditional row crop and animal production. Several system designs have shown superior performance in terms of yields and returns on investment. These designs include alley cropping of grains and forages in alleys between rows of trees, grazing of pasture under hardwood trees, and the production of trees, forages, and income-producing shrubs at the margins of crop fields in riparian zones. Other system designs that originate in tropical climates show promise for improving yields and/or returns as well. This project has also demonstrated that these mixed-production systems have the ability to capture excess nutrients from agricultural production, protecting groundwater and surface water resources. Despite their superior economic and environmental performance (shown by this project and others), adoption has been low in the
Midwest relative to other regions of the US. Exisiting adoption has been concentrated among producers wishing to shift to forest production, those wishing to add a forestry component to their crop production, or those forced to adopt water protection strategies through government regulation. Future research must address social dynamics and barriers to increase adoption.
Impacts
Government and extension professionals now have several models for mixed-production systems that producers and landowners can utilize. This project has provided guidance on system design to minimize competition between system components to maximize economic return while also enhancing environmental services. As increasing regulation of production practices occurs to improve water quality within the region, more acreage will be placed under these systems, allowing producers to maintain farm viability while also achieving water quality goals.
Publications
- von Kiparski, G.R. and A.R. Gillespie. 2005. Plant productivity vector changes within a humid-temperate hardwood alley-cropping system. In: S. Jose and A. Gordon (eds.). Biophysical Interactions in Agroforestry. Kluwer Academic Publishers, Dordrecht, The Netherlands.
- Gillespie, A.R., D.B. Mengel, W.L. Hoover, P.E. Pope, J.R. Seifert, D.J. Biehle, T. Stall, S. Jose, and T.J. Benjamin. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: I. Production physiology. Agroforestry Systems 48:25-40.
- Benjamin, T.J., W.L. Hoover, J.R. Seifert, and A.R. Gillespie. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: IV. The economic return of ecological knowledge. Agroforestry Systems 48:79-93.
- Benjamin, T.J., P.I. Montanez, J.J. Jimenez Osornio, and A.R. Gillespie. 2001. Carbon, water, and nutrient flux in Maya homegardens in the Yucatan peninsula of Mexico: System design and management. Agroforestry Systems 53:103-111.
- von Kiparski, G.R. and A.R. Gillespie. 2001. The relative importance of water and nutrient competition in a temperate agroforestry system: modeling approaches. Abstract - 2nd International Symposium on Modelling Cropping Systems, Florence, Italy.
- Gillespie, A.R., M. Ferguson-Bocanegra, and J.J. Jimenez Osornio. 2003. The propagation of Ramon (Brosimum alicastrum Sw.) in Mayan homegardens of the Yucatan peninsula of Mexico. New Forests 27:25-38.
- Gillespie, A.R. 2004. Temperate silvopastoral experience in the USA: Practices and principles. 2nd International Symposium on Silvopastoral Systems, February 9-11, 2004, Merida, Mexico.
- Jose, S., A.R. Gillespie, and S.G. Pallardy. 2004. Interspecific interactions in temperate agroforestry. In: P.K.R. Nair, M.R. Rao, and L.E. Buck (eds.). New Vistas in Agroforestry. Kluwer Academic Publishers, Dordrecht, The Netherlands. 480 pp.
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Progress 10/01/03 to 09/29/04
Outputs
Data analysis for row cropping and silvopastoral systems has been completed, providing information on the effects of tree maintenance on intercrop productivity and the sustainability of these systems. Research results are being compiled into publications and disseminated through journals and professional and technical meetings.
Impacts
Continued experimentation is providing information on which agricultural production methods have the greatest impact on environmental sustainability and which specific mitigation methods involving trees and woody crops are most useful. Examination of water flux and quality data indicate that trees established in row crop plantings remove excess nitrogen from waters leaching beyond the root zones of crops. This "safety net" effect contributes to improved water quality.
Publications
- Jose, S., A.R. Gillespie, and S.G. Pallardy. 2004. Interspecific interactions in temperate agroforestry. In: P.K.R. Nair, M.R. Rao, and L.E. Buck (eds.). New Vistas in Agroforestry. Kluwer Academic Publishers, Dordrecht, The Netherlands. 480 pp.
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Progress 10/01/02 to 09/30/03
Outputs
Experimental data on alley cropping, silvopastoral, and riparian zone agroforestry systems continues to be collected. Initial data indicate that alley cropping systems serve a nutrient-retention function, minimizing nutrient loss to surrounding ecosystems. This function is not seen in silvopastoral systems as forage systems seems to be much better at retaining nutrients and trees do not help in this function. Riparian zone research indicates that local topography greatly impacts efficacy of buffer strips as overland flow concentration can bypass the filtering function of buffers, though more experiments still need to be conducted. Importing tropical production methods shows great promise for enhancing environmental sustainability in agriculture though specific production methods will be limited to certain landscape possibilities and farm type or size.
Impacts
Continued experimentation is providing information on which agricultural production methods have the greatest impact on environmental sustainability and which specific mitigation methods involving trees and woody crops are most useful.
Publications
- Gillespie, AR, DM Bocanegra-Ferguson, and JJ Jimenez-Osornio. 2004. The propagation of Ramon (Brosimum alicastrum Sw.) in Mayan homegardens of the Yucatan peninsula of Mexico. New Forests 27:25-38
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Progress 10/01/01 to 09/30/02
Outputs
Spatial variation and tree root pruning effects on soil fertility in alley cropping show little impact in year 15. Total (0-100 cm depth) soil C and N, A horizon thickness, soil microbial biomass, available N, and nitrification and mineralization potential were not significantly different after tree root pruning and barrier installation in Year 10. In conclusion, the effects of tree root pruning and alley row position on soil fertility are not apparent, possibly due to the formation of a uniform walnut root network that regulates soil fertility in Year 15. In examining water versus nitrogen limitation, parameterization of a computer simulation model was completed. The model shows mineral nitrogen availability is very sensitive to soil water content. Soil water content constrains nitrogen availability to plants and is the principle factor constraining alley productivity for the SEPAC site. A modeling approach was used to examine system productivity changes over time.
Parameterization of an agroforestry model was completed for the black walnut-maize system in Indiana. Model prediction of alley and tree productivity versus observed were compared. Sensitivity analysis showed which parameters were mostly responsible for controlling system productivity. Nitrogen dynamics were quantified because of nitrogen leaching. Nitrate-N was higher in soil leachates collected from under the rooting zone in the year 10 tree root pruning treatment compared to no root pruning. 15-N labeled fertilizer nitrogen was higher in soil leachates collected from under the rooting zone in the year 10 tree root pruning treatment compared to no-root pruning. Residual mineral nitrogen was higher in soil extracts collected from the 0-90cm depth under the rooting zone in the year 10 tree root pruning treatment compared to no root pruning. Nitrate-N was significantly higher in 90-cm soil leachates for a monocultural corn area compared to all locations within the agroforestry site.
Therefore, black walnut trees reduce the movement of fertilizer N, in the form of nitrate-N, toward drainage waters beneath the rooting zone. Research continues in the forage systems and tropical systems that have temperate application.
Impacts
Current research progress indicates that trees as components of the agricultural landscape can play a significant role in reducing pollution due to nitrogen leaching from crop production.
Publications
- Benjamin, T.J., P.I. Montanez, J.J.M. Jimenez, and A.R. Gillespie. 2001. Carbon, water, and nutrient flux in Maya homegardens in the Yucatan peninsula of Mexico. Agroforestry Systems 53:103-111.
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Progress 10/01/00 to 09/30/01
Outputs
Forage production under tree plantations - forage quality generally increases during the growing season with the final harvest having the greatest quality. Forage quality is uniform across plots, regardless of position relative to tree cover. Forage quantity under trees shows spatial variation, with most species showing greater growth in the center of alleys away from trees, where more light and rain fall. First harvests in the season are economical, with decreasing returns through the season at a tight tree spacing (20 feet between tree rows). Forage water use and transpiration are relatively uniform across plots under trees. Variability exists among forage species for some locations relative to tree position. Trees with vigorous forage competitors actually used more water than when grown without surrounding forage cover (bare control plots). We feel that this may be due to the effect of forage plant roots on water infiltration. Pasture under tree plantations -
forage quality again exhibits an increase with time during a growing season. Late season (September) quality increased only for those plots grazed with continuous or rotational grazing. Grazing on a short-term basis does not increase soil compaction at the base of trees in a plantation. Crop production under tree plantations - Hourly water content at the 0-30 cm depth, measured using water content reflectometers during the period 2001 May 15 - 2001 August 30 showed that Control plots (corn) were drier on average than Agroforestry plots. Root pruning in 1995 increased water content compared to no-root pruning. Neutron probe measurements on a biweekly basis from 2000 May 10 - 2000 October 30 showed that Control plots (corn) were drier on average than Agroforestry plots. Root pruning in 1995 increased water content compared to no-root pruning. Light (PAR) penetration data measurements on July 30 2000 and 2001 showed that aboveground branch pruning treatment (for quality hardwood lumber
and veneer) increased light penetration by 20%. Light penetration in the cropping alley was 45% on average of the control corn plots. Tree root distribution data from 2000, showed that the tree rooting was lower in the 1995 root pruning treatment plots, although some tree root ingrowth had occurred. 2001 root measurements showed an inverse relationship between tree and corn rooting density. Crop yield is higher in year 2001 versus 2000. This was true for corn harvest across the state of Indiana and probably related to better seedbed moisture and the 4-week earlier planting in the year 2001 versus 2000 on our sites. The difference between root-pruned versus no-root pruning treatments was higher in year 2001 versus year 2000. Agroforestry corn yields were lower than control corn in both years 2000 and 2001. Nitrate in 30-cm and 100-cm leachates, from May 2000 - June 2001, show that the agroforestry plots had lower nitrate-N concentrations than the control corn sites. No apparent
difference in nitrate-N concentration in the root pruned versus no-root-pruned plots was seen.
Impacts
More landowners are becoming interested in agroforestry alternatives. A trend is appearing that indicates agroforestry is being considered as land changes generations in a family. As our research shows that these systems provide a greater return than either agriculture or forestry, and that they reduce agricultural environmental impacts by, for example, reducing nitrate leaching below the crop zone, they provide excellent alternatives for land use.
Publications
- Jose, S. A.R. Gillespie, J.R. Seifert, and P.E. Pope. 2001. Comparison of minirhizotron and soil core methods for quantifying root biomass in a temperate alley cropping system. Agroforestry Systems 52: 161-168.
- Von Kiparski, G. and A.R. Gillespie. 2001. The relative importance of water and nutrient competition in a temperate agroforestry system - modelling approaches. Abstract. 2nd International Syposium on Modelling Cropping Systems. July 16-18, Florence, Italy. European Society of Agronomy.
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Progress 10/01/99 to 09/30/00
Outputs
The goal of this research program is to continue to seek and test appropriate and feasible agroforestry systems that areenvironmentally and economically sustainable for the region. An interdisciplinary approach is utilized to examine the interactions of the plant, animal, and the physical and chemical environmental components of integrated production. Work on successful alleycropping systems was published this year. Results indicate that wider-spaced systems optimize returns to farmers when water competition is managed. Returns well beyond traditional agriculture or forestry can be realized when both are combined in alley cropping systems. This past year has been utilized to establish new trials on both private land and on Purdue research agricultural and forest land. Forage trials have been initiated with the Purdue Agronomy department to determine which forages grow well in combination with hardwood trees in alleys. Preliminary results show that grasses are more
aggressive and compete better with trees for moisture relative to legumes. Grass-legume mixtures also perform well. Water use by trees, however, was greater with the more aggressive forages, contrary to our hypotheses. Our research is now exploring this phenomenon. Also, trials with sheep grazing were initiated with the Department of Animal Science. Early grazing results indicate the need to control animal behavior more in rotational systems than in continuous grazing systems due to impacts on trees at the tree base. Alleycropping trials continue with the examination of nutrient cycling, and modelling efforts have begun for this system. These systems were also instrumented this year to examine nutrient and water flux below-ground to understand water sharing among system components and also the impacts of integrated tree-crop systems on water quality. Soil solutions were collected in these systems and will be analyzed this fall.
Impacts
nformation is now published on the alleycropping system. Existing trials on Purdue and private lands have been used for tours of producer groups (both crop and tree groups) to demonstrate alternative production systems. Interest is growing among landowners and producers for these alternative production systems as well as for alternative forest crops such as medicinal herbs.
Publications
- Benjamin, T.J., W.L. Hoover, J.R. Seifert, and A.R. Gillespie. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: IV. The economic return of ecological knowledge. Agroforestry Systems 48:79-93.
- Gillespie, A.R., S. Jose, D.B. Mengel, W.L. Hoover, P.E. Pope, J.R. Seifert, D.J. Biehle, T. Stall, and T.J. Benjamin. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: I. Production Physiology. Agroforestry Systems 48:25-40.
- Jose, S., A.R. Gillespie, J.R. Seifert, and D.J. Biehle. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: II. Competition for water. Agroforestry Systems 48:41-59.
- Jose, S., A.R. Gillespie, J.R. Seifert, D.B. Mengel, and P.E. Pope. 2000. Defining competition vectors in a temperate alleycropping system in the midwestern USA: III. Competition for nitrogen and litter decomposition dynamics. Agroforestry Systems 48:61-77.
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Progress 10/01/98 to 09/30/99
Outputs
Work on successful alleycropping systems is being published currently. Results indicate that wider-spaced systems optimize returns to farmers when water competition is managed. Returns well beyond traditional agriculture or forestry can be realized when both are combined in alley cropping systems. This past year has been utilized to establish new trials on both private land and on Purdue research agricultural and forest land. Forage trials have been initiated with the Purdue Agronomy department to determine which forages grow well in combination with hardwood trees in alleys. Preliminary results show that grasses are more aggressive and compete better with trees for moisture relative to legumes. Grass-legume mixtures also perform well. Also, trials with sheep grazing were initiated with the Department of Animal Science. Early grazing results indicate the need to control animal behavior more in rotational systems than in continuous grazing systems due to impacts on
trees at the tree base. Alleycropping trials continue with the examination of nutrient cycling, and modelling efforts have begun for this system. These systems were also instrumented this year to examine nutrient and water flux below-ground to understand water sharing among system components and also the impacts of integrated tree-crop systems on water quality. Soil solution measurements will begin this fall. In related work with woody perennials on farms, economic modelling has indicated that farm-grown woody biomass is a feasible fuel source for Indiana utilities wanting to co-fire biomass with coal to reduce net carbon emissions. This activity would also benefit the environment by removing marginal farm lands from crop production and increasing landscape diversity.
Impacts
Information is now being published on the alleycropping system for dissemination. Existing trials on Purdue and private lands have been used for tours of producer groups (both crop and tree groups) to demonstrate alternative production systems.
Publications
- Nienow, S., K.T. McNamara, A.R. Gillespie, and P.V. Preckel. 1999. A model for the economic evaluation of plantation biomass production for co-firing with coal in electricity production. Agricultural and Resource Economics 28:106-118.
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Progress 10/01/97 to 09/30/98
Outputs
Significant progress has been made with alleycropping systems in terms of increasing crop yields and economic efficiency of the combined tree-crop system. Completed research shows that water is a limiting resource, even in the Eastern Corn Belt Region. Competition for water between trees and crops limits crop yields and crop rotations. However, simple management techniques can be used to periodically prune the roots of trees, limiting competition. When competition for water is negated, crop yields return to normal under black walnut and red oak tree species, despite shade of canopies. Competition for nutrients is present, but limited due to fertilization and the partitioning of nutrient sources. While cropping provides farmers with returns of five to 7 percent in the region, adoption of the combined agroforestry system can provide yields of up to 18 percent with proper management. New research has been initiated investigating nutrient cycling and leaching of nitrates
to ground water in the mixed system. New research has also been initiated in the hydrology of silvopastoral systems and riparian zone systems. Forage trials are also being conducted to determine which forages will do best with water and light competition from trees in the Eastern Corn Belt region. This work will complement work in Missouri.
Impacts
(N/A)
Publications
- Jose, S. 1997. Interspecific interactions in alleycropping: The physiology and biogeochemistry. PhD thesis, Forestry and Natural Resources, Purdue University, West Lafayette, IN. 171 pp.
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Progress 10/01/96 to 09/30/97
Outputs
This project is in it's initial phase. Alley cropping systems using black walnut and red oak trees with corn have been examined for ecological interactions that control crop yields. Preliminary data suggest that below-ground processes limit crop production rather than above-ground competition for light. When root barriers were placed between crop and tree root systems, crop yields returned to normal levels (similar to monoculture yields). Thus, water and nutrient competition are under investigation to determine relative limitations to crop production in alley cropping. Other systems, including silvopastoral systems and home gardens are also being investigated with field trials and also study at sites in the temperate, subtropical, and tropical zones.
Impacts
(N/A)
Publications
- No publications reported this period
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