Enhancing the Economic and Environmental Competitiveness of Small Farms Through Agroforestry

2002 Annual Report for LS02-136

Project Type: Research and Education
Funds awarded in 2002: $189,600.00
Projected End Date: 12/31/2004
Region: Southern
State: Florida
Principal Investigator:
Shibu Jose
University of Florida

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 from two universities will be working with farmers, extension educators and USDA Natural Resource Conservation Service personnel to accomplish the project objectives. Standard tree and crop measurement procedure will be employed to determine system productivity, and established protocols will be 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 field installations will encompass two southern states (Florida and Georgia) and the findings of our project will have direct applications to the entire southeastern U.S. The project results will be disseminated through farm tours, field days, extension and trade publications, journal papers, television and radio, and through the internet. The network of county extension faculty will also be actively involved in information dissemination and outreach activities along with the project investigators.

Objectives/Performance Targets

  1. 1.Examine system design (tree spacing, and tree-crop combinations) and its role on system productivity
    2.Determine the biophysical interactions between system components (i.e., trees and crops) in order to optimize production potential of each component
    3.Evaluate alley cropping and silvopastoral systems for their ability to reduce ground water non-point source pollution from agricultural chemicals
    4.Determine the economic benefits of alley cropping systems


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 allevioate 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.

The agroforestry project has enjoyed important exposure in the scientific community, being the subject of two conference presentations at the ASA/CSA/SSSA meeting in Indianapolis in November 2002. One M.S. thesis has been copmpleted and one Ph.D. dissertation will be completed later in 2003. One manuscript has been accepted and one is under review in Agroforestry Systems. In addition, the research site was observed by local farmers and landowners who attended a Field Day in June 2002 at the Jay, FL, experiment station, where the research is conducted.

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 will be 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, will be periodically adjusted in size with electric fence to equalize forage allowance. Available forage and nutritive value will be monitored during the grazing period. Cows will be 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] will be used as a model for a new publication showing the profitability of including livestock, forestry, and wildlife in land management.

North Florida Research and Education Center, Quincy, FL: A 50 ac, 8-yr-old loblolly pine plantation will be evaluated for pine straw production and groundwater nitrate levels (using lysimetry as explained earlier) and economic returns. This subproject was initiated in March 2003.

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.