AGROFORESTRY IN THE SOUTHERN U.S.: IMPORTANT LESSONS LEARNED
J. D. KUSHLA *
Department of Forestry, Mississippi State University, USA.
H. G. GORDON
First Tennessee Bank, Mississippi State University, USA.
R. K. GRALA
Department of Forestry, Mississippi State University, USA.
W. D. JONES
Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, USA.
J. JONES
Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, USA.
M. SHANKLE
Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, USA.
*Author to whom correspondence should be addressed.
Abstract
An agroforestry system was studied in northern Mississippi. Loblolly pine (Pinus taeda) and shortleaf pine (Pinus echinata) bare root seedlings were planted on the site in March of 2005. Trees were mechanically planted in sets of two rows at a 3.0 m x 2.1 m spacing with a 12.2 m alley between respective sets of rows. Four replications of each tree species and crops were planted. Within the alley, the agricultural crops: corn (Zea mays), grain sorghum (Sorghum bicolor), soybeans, (Glycine max), and switchgrass (Panicum virgatum) were randomly assigned to agronomic scale research plots of 3.96 m x 30.48 m directly adjacent to either side of the 2-row tree planting in a complete randomized block design. Heights and diameters of pines were measured in 2008 and 2009; crop yields were estimated through random sampling of quadrats and calculated. To assess agroforestry impacts on wildlife habitat, herbaceous vegetation was identified and measured in randomly sampled meter-squared quadrats. Breeding bird surveys were also conducted in forest, pasture, and agroforestry land uses. None of the agronomic crops included in the study had a significant impact on total tree height, ground line diameter, or volume index. A Chi-square analysis of the herbaceous vegetation survey revealed that alley cropping significantly increased the species richness of herbaceous vegetation found adjacent to crop plots. A breeding bird survey in 2009 revealed that the agroforestry habitat had the greatest diversity of bird species, and second-highest number of observations. The eastern meadowlark (Sturnella magna), which is in decline, was found in the agroforestry habitat. Future research should include considerations for wildlife herbivory, such as wider crop alleys, larger crop plots, planting to scale, and fencing.
Keywords: Agroforestry, alley cropping, loblolly pine, shortleaf pine, wildlife habitat