Long-Term Cropping System, Tillage, and Poultry Litter Application Affect the Chemical Properties of an Alabama Ultisol

Sustainable agricultural practices have been steadily increasing in the last couple of decades. These management practices frequently involve cover crops, less or no-tillage, and organic fertilization. In this study, we evaluated the effects of cropping systems, tillage and no-tillage, and the application of poultry litter (PL) on selected soil physicochemical properties and soil test nutrients. Soil samples were collected from the topmost surface (0–5 cm) and subsurface (5–10 cm) layers. The general effect trend was PL application > no-tillage > cover crop > cropping type. There were more statistically significant ( P ≤ 0.05) correlations between the 18 soil attributes at the topmost surface than at the subsurface. This could be due to the accumulation of external C inputs and nutrients by crop residues and PL application as well as the retaining effects of no-tillage on less mobile nutrient components. Because of their high mobility and volatile nature, total nitrogen (N), ammonia-N (NH 4 + -N), and nitrate-N (NO 3 − -N) levels varied greatly (high standard deviations), showing no consistent patterns among the treatments. Compared to the soybean cropping system, corn, especially with the wheat cover crop, contributed more to the total carbon (C) and sulfur (S) in the topmost surface soils (0–5 cm). Poultry litter application greatly increased pH, cation exchange capacity (CEC), base saturation, magnesium (Mg), phosphorus (P), calcium (Ca), sodium (Na), potassium (K), manganese (Mn), copper (Cu), and zinc (Zn) in both soil layers. Contrast comparisons revealed that PL application had more of an effect on these soil chemical properties than no-tillage and cropping systems. These results will shed light on developing better nutrient management practices while reducing their runoff potentials.