Crop rotation and nitrogen input effects on soil fertility, maize mineral nutrition, yield, and seed composition
Knowledge of complex relationships between soils, crops, and management practices is necessary to develop sustainable agricultural production systems. Objectives were to determine how maize (Zea mays L.) would respond to monoculture (C-C), 2-yr rotation (C-S) with soybean [Glycine max (L.) Merr.], or 4-yr rotation (C-S-W/A-A) with soybean, wheat (Triticum aestivum L.), and alfalfa (Medicago sativa L.) under different N input levels. We evaluated N fertilizer input (8.5 or 5.3 Mg/ha yield goal, or no N) and crop rotation (C-C, C-S, or C-S-W/A-A) treatment effects on soil minerals (N, P, K, S, Ca, Mg, Fe, Mn, and Zn) and their subsequent effect on shoot dry weight and mineral concentrations, grain yield, and grain composition (oil, starch, and mineral concentrations) using univariate and multivariate statistical tests. Soil under C-S-W/A-A rotation had greater NO3–N and less extractable P than other rotations. Significant input x rotation interactions revealed that shoot concentrations of N, Ca, and Mg were less while P, K, and Zn were greater at no N input for the C-C rotation compared with other N input/rotation treatments. Increased soil NO3–N, increased plant Ca concentration, and increased grain N and grain S concentrations were most important in differentiating C-S-W/A-A rotation from C-C and C-S rotation treatments. No N input resulted in less yield and kernel N concentration within the C-C and C-S rotations but not C-S-W/A-A. Thus, growing maize in extended rotations that include forage legumes may be a more sustainable practice than growing maize in either monoculture or 2-yr rotation with soybean.