Corn yield and yield stability under varying nutrient management, crop rotation, and rainfall

Long-term yield performance and yield stability of common cropping systems needs to be simultaneously assessed at various fertility regimes. Based on a consecutive 19-year field trial, including eight fertilization treatments with different combinations of nitrogen (N), phosphorus (P), potassium (K) and recycled manure (RM), the effects of fertilization and crop rotation on corn (Zea mays L.) yield performance and stability were evaluated. The results showed that although the fertility regimes had greater influence on yield increase (average 2.94 Mg ha-1) than crop rotation (averge 0.42 Mg ha-1) [corn-corn-soybean (Glycine max)], the rotation effect on yield increase was almost 51% of that of fertilizer N under low nutrient availability conditions. A synergistic effect between RM and crop rotation was observed in the present study, in detail, yield-increasing effect of RM, on average, were 0.98 and 1.04 Mg ha-1 in continuous and rotation cropping systems, respectively. Stability analysis revealed that RM improved yield stability under nutrient absence conditions rather than under balanced fertilization conditions. Moreover, crop rotation substantially improved yield stability. High and stable yields were obtained in test years with arid index ranged from 1.08 to 1.16, which can be regarded as proper environment in this region. Ranking the statistical parameters indicated that they are similar in general, and considering the amount of RM resource, NPM which achieved high and stable yield was the most recommendable fertility regime in this region.