Enhancing the Economic and Environmental Competitiveness of Small Farms Through Agroforestry
Economic returns from the farming enterprise have been decreasing steadily over the years while environmental problems due to intensive agriculture have been increasing at an alarming rate. Reduced biodiversity, increased erosion, lower soil fertility, greenhouse gas emission, and non-point source pollution of ground water and streams have all been identified as problems associated with intensive monocultural systems. Small farms are fast disappearing from the agricultural landscape threatening the integrity of rural communities. Agroforestry, the deliberate growing of trees or shrubs on agricultural lands with agronomic crops or pasture and/or animals, offers promise as an alternative land-use practice with potential for alleviating some of these environmental and economic problems. Agroforestry is gaining attention in the U.S. through the efforts of USDA National Agroforestry Center, USDA ARS, USDA NRCS, USDA Forest Service, Association for Temperate Agroforestry, and various land-grant universities. Federal incentive programs are being implemented through the 1996 USDA Farm Bill to help landowners establish trees on their farmlands. With millions of acres under widely spaced pecan orchards, marginal cropland, and rangeland the Southeast offers a great potential for agroforestry practices. Some of the key elements to a successful small farming enterprise such as, diversification of farm income, reduced production costs, and increased economic returns can all be achieved through agroforestry while alleviating some of the environmental problems associated with monocultural systems. Through the three year research outlined here we will examine two major forms of agroforestry systems (alley cropping and silvopasture) for their ecological and economic sustainability and environmental benefits. We envision four major objectives. These are: 1) Examine system design (tree spacing, and tree-crop system configurations) and its role on system productivity (tree, crop, and livestock production potential), 2) Determine the biophysical interactions between system components, 3) Evaluate alley cropping and silvopastoral systems for their ability to reduce ground water non-point source pollution from agricultural chemicals, and 4) Determine the economic benefits of agroforestry systems. The information gathered through the study will be used to educate farmers and landowners about the potential for agroforestry as an alternative land-use practice in the Southeast. A team of scientists are working with farmers and extension educators to accomplish the project objectives. Standard tree and crop measurement procedure are employed to determine system productivity, and established protocols are used to quantify tree-crop interactions and environmental benefits. Economic analysis will take into account both spatial and temporal aspects. The analysis will be conducted on a unit area over a specified period for each agroforestry system. Further, we propose to use the social accounting matrix (SAM) modeling approach to determine multiplier impacts of agroforestry on the regional economy and employment. The project outcome will help to design better sustainable tree-crop-animal integrated systems that minimize negative component interactions, decrease nutrient leaching, and increase economic returns. The findings of our project will have direct applications to the entire southeastern U.S. The project results are being disseminated through farm tours, field days, extension and trade publications, and journal papers. The network of county extension faculty is also be actively involved in information dissemination and outreach activities along with the project investigators.
1.Examine system design (tree spacing, and tree-crop combinations) and its role on system productivity (years 1 through 3)
2.Determine the biophysical interactions between system components (i.e., trees and crops) in order to optimize production potential of each component (years 1 through 3)
3.Evaluate alley cropping and silvopastoral systems for their ability to reduce ground water non-point source pollution from agricultural chemicals (years 1 through 3)
4.Determine the economic benefits of alley cropping systems (year 3)
Accomplishment by study location are outlined below:
West Florida Research and Education Center, Jay FL (all objectives): A mature pecan-cotton alley cropping system was established in Spring 2001, as a principal research focus in Jay, FL. The system is a RCBD consisting of 10 plots, of which 5 are “trenched” and 5 are “no trench” (i.e., control). Trenched plots have a 3 ft deep plastic liner installed at a distance of 5 ft from the center of tree, for the length of the plot, to prevent tree roots from interacting with the adjacent cotton. To quantify nutrient competition, 15N fertilizer (ammonium sulfate, 5% enrichment) was applied to selected microplots at the same time, rate and formulation as the regular fertilizer being applied to the field. Six plants (above-ground portions only) from the center of each microplot were harvested at physiological maturity (early October), and were separated into stem, leaf, square, and boll components. Foliar samples from trees were also collected. Nitrogen mineralization was quantified by the use of in-situ soil mineralization bags. Grounwater nitrate and ammonium levels were monitored using lysimeters at 30 cm and 90 cm depths in both the treatments. Initial findings indicate that competition for nitrogen is present in the system and trenching has the potential to alleviate the intensity of competition. Mature pecan trees are able to reduce the amount of nitrate in in-situ groundwater. Yields were also lower in untrenched plots, indicating competition for nitrogen and water from tree roots.
Four other trials with loblolly pine and longleaf pine as the tree components and cotton as the agronomic component were also established in Spring 2001. Data on tree growth and cotton yield have been collected for the past three growing seasons. We initiated the “trenched” and “non-trenched” treatments in February 2004 to begin resource allocation and utilization experiments in the summer of 2004.
A new treatment in the pecan-cotton alley cropping was initiated in the summer of 2003 where poultry litter was applied instead of conventional inorganic fertilizer. Phosphorus movement in the soil and cotton yield responses were also monitored. Results from this trial will be presented at the World Agroforestry Congress in Orlando in June 2004.
The agroforestry project has enjoyed important exposure in the scientific community during the reporting period, being the subject of several conference presentations at the ASA/CSA/SSSA meeting in Denver, The North American Agroforestry Conference in Corvallis, OR, and an invited seminar at the School of Environmental Science and Management, Southern Cross University in Australia. One Ph.D. dissertation was completed in 2003. Two manuscripts were published (both in Agroforestry Systems), four are in press (Agroforestry Systems, Journal of Crop Production, Plant and Soil and Forest Ecology and Management), and two are under review (Agroforestry Systems and Biology and Fertility of Soil). In addition, the research site was observed by local farmers and landowners who attended a Field Day in June 2003 at the Jay, FL, experiment station, where the research is conducted. A second field tour was conducted for the Center for Subtropical Agroforestry group in June. An extension publication was published by the UF Cooperative extension service on alley cropping potential for the southeast.
Range Cattle Research and Education Center, Ona, FL(Objectives 1, 3, and 4): A 40 ac, 20-yr-old bahiagrass pasture was planted with slash pines (4′ x 8′ x 40′ spacing) in 1992 (Kalmbacher, 2000). In 2002, 8, 1 ha paddocks were delineated and four of these with uniform pine stands were selected and maintained with pines. Pines were removed from the other four paddocks in December 2002, and all paddocks were fenced. All paddocks were stocked with two, pregnant cow-calf pairs from June to September, but paddocks without pines, where available forage is expected to be more than that in paddocks with pines due to shading, were periodically adjusted in size with electric fence to equalize forage allowance. Available forage and nutritive value were monitored during the grazing period. Cows were maintained as a group from October to May and exposed to bulls from March to May. The main live-animal response variable used to evaluate treatments will be cow and calf weights at weaning, the later being used to calculate live-weight gain/ha. The principal economic measure will be the amount of land required to sustain an animal unit (cow-calf pair) on pastures with or without pines.
The classic publication by Anderson & Hipp (1975) [The publication “Requirements and returns for 1000-cow beef herds on flatwoods soils in Florida” shows profitability using varying amounts of pasture and native range in a ranching operation] is used as a model for a new publication showing the profitability of including livestock, forestry, and wildlife in land management. Preliminary results were presented at a meeting in Milton in May 2003.
North Florida Research and Education Center, Quincy, FL: A 50 ac, 8-yr-old loblolly pine plantation is being evaluated for pine straw production. Two types of nutrient amendments (poultry litter and inorganic fertilizer) are being evaluated as a new treatment. Tree growth, pine straw production, and groundwater nitrate levels (using lysimetry as explained earlier) and economic returns are being quantified. One conference presentation was made based on the preliminary data at the Southern Silvicultural Research Conference in Biloxi, MS.
Impacts and Contributions/Outcomes
Outcome from the agroforestry project will be used to provide a profile of the interaction effects of trees and crops on the ecological and economic sustainability of agroforestry as a land use practice. Findings from crop yields, soil moisture measurements, and water, soil and plant tissue analyses, will shed light on crop and tree root activity, and their effects on site environmental conditions. This knowledge will help to improve our basic understanding of temperate agroforestry systems, so that better systems can be created, with tighter nutrient cycling, reduced groundwater pollution, and higher economic returns.
Ultimately, it is hoped that this research will encourage farmers and landowners to adopt agroforestry practices. The researchers believe that such systems can help to diversify and strengthen the family farm, by providing alternate forms of income at various times of the year, while utilizing land that would otherwise remain unused. We also hope that landowners would be encouraged to plant longleaf pines on their property, given the possibility of incorporating this species with other more immediate cash crops. The prospect of reducing nitrate levels in groundwater is also an exciting possibility for these types of systems, which is a vision that we hope landowners are able to catch.
1.Jose, S., Gillespie, A.R., and Pallardy S.G. Interspecific interactions in temperate agroforestry. In New Vistas in Agroforestry. Nair, P.K.R., Rao. M.R., and Buck, L.E. (ed.), Kulwer Academic Publishers, Dordrecht, The Netherlands. In press (invited).
2.Jose S., Allen S.*, and Nair P.K.R. 2003. Ecological interactions: Lessons from temperate alley cropping systems. In Agroforestry. Batish S. and Singh H.P. (eds). Haworth Press, New York. In press (invited)
1.Wanvestraut, R.*, Jose, S., Nair, P.K.R., and Brecke, B.J. Competition for water in a pecan-cotton alley cropping system in the southern United States. Agroforestry Systems 60:167-179.
2.Jose, S., Gillespie, A.R., and Pallardy S.G. Interspecific interactions in temperate agroforestry. Agroforestry Systems 61: (in press)
3.Lee, K.H.* and Jose, S. 2003. Soil respiration and microbial biomass in a pecan-cotton alley cropping system in southern USA. Agroforestry Systems 58:45-54.
4.Allen, S.*, Jose, S., Nair, P.K.R., and Brecke, B.J. Competition for nitrogen in a pecan-cotton alley cropping system in the southern United States. Plant and Soil (in press)
5.Jose, S., Allen, S.*, and Nair, P.K.R. Tree-crop interactions: Lessons from temperate alley cropping systems. Journal of Crop Production (in press)
6.Allen, S.*, Jose, S. Nair, P.K.R., Brecke, B.J., Ramsey C.L. 2004. Experimental evidence for the safety-net hypothesis. Forest Ecology and Management (in ress)
Allen, S. 2003. Nitrogen dynamics in a pecan-cotton alley cropping system. Ph.D. dissertation, University of Florida, Gainesville, FL.
1.Jose, S. 2003. Tree-crop interactions in temperate alley cropping: Ecological principles and evaluation techniques. Ecology Seminar Series, School of Environmental Science and Management, Southern Cross University, October 3, Lismore, NSW, Australia (invited).
2.Lee, K.H.* and Jose, S. 2003. Soil respiration and microbial biomass responses to soil water and nitrogen source in a pecan-cotton temperate alley cropping system. Eight North American Agroforestry Conference, June 22-25, Corvallis, Oregon.
3.Zamora, D.* and Jose, S. 2003. Competition for light between pecan and cotton in a pecan-cotton temperate alley cropping system. Eight North American Agroforestry Conference, June 22-25, Corvallis, Oregon.
4.Allen, S.C.*, Jose, S., Nair, P.K.R., Nair, V.D., Graetz, D. 2003. Competition for nitrogen in a temperate alley cropping system with pecan and cotton. Eight North American Agroforestry Conference, June 22-25, Corvallis, Oregon.
5.Allen, S.*, Jose, S., Nair, P.K.R., Nair, V.D., Graetz, D., and Ramsey, C.L. 2003. Nitrogen mineralization in a temperate alley cropping system in the southern United States. ASA-CSSA-SSSA Annual Meeting, November 2-6, Denver, CO.
6.Allen, S.*, Jose, S., Nair, P.K.R., Brecke, B.J, and Ramsey, C.L. 2003. Experimental evidence for the safety-net hypothesis from a temperate alley cropping system. ASA-CSSA-SSSA Annual Meeting, November 2-6, Denver, CO.
7.Nowak, J., Osiecka, A., Hochmuth G., Lee, K.*, and Jose, S. 2003. Nitrate leaching and tree growth following fertilization with diammonium phosphate (DAP) or poultry litter in two-year-old slash pine and loblolly pine plantations. Twelfth Biennial Southern Silvicultural Research Conference, February 24-28, Biloxi, MS.