Chemical, Physical and Biological Properties of a Marginal Soil as Influenced by Tillage and Broiler Litter Application.

Erosion changes the soil properties, mainly because it removes surface soil rich in organic matter and exposes lower soil layers. Many soils in Mississippi were degraded by erosion and nutrient depletion when these were row-cropped years ago.  A study was initiated in 2005 in an eroded Loring silt loam (fine silty, mixed, thermic, Glossic Fragiudalf) soil to determine if soil and crop management along with poultry manure application affect the physical, chemical and biological properties of an eroded soil. The soil has a fragipan in the subsoil that is restrictive to root growth and water infiltration. We hypothesized that the combination of deep tillage to loosen the subsoil and long-term poultry manure application to provide nutrients and organic matter and surface tillage to incorporate poultry manure into the soil has the potential of improving soil properties and restoring marginal land. A corn-wheat-soybean rotation was used as our cropping system. The results of initial soil analysis taken at 0-15 cm depth indicated that the eroded soil was low in pH (4.2 - 4.5), N (0.04-0.06%), C (0.4-0.6%), P (7-8 mg kg^-1) and high in bulk density (1.38 g cm ^-3). Biennial broiler litter application to corn under a tillage system resulted in increasing soil pH by 0.71 unit, soil total C by 20%, microbial biomass C by 41% (143 to 245 mg kg^-1, total N by 8%, soil test P levels by 55% (from 6.7 to 14.9 mg kg^-1), soil Cu content by 51% (from 0.94 to 1.93 mg kg^-1) and soil Zn levels by 60% (from 0.86 to 2.14 mg kg^-1). Soil bulk density decreased by 3% (from 1.38 to 1.34 g cm ^-3). This indicates combination of poultry manure, soil and crop management practices has the potential on sequestering C and nutrients in the soil and in the long-term resulting in restoring degraded areas to productive croplands.