Recycling animal manure for crop production has potential to enhance grain yield while improving soil quality. The objective of this study was to evaluate the influence of variable rate manure versus variable rate nitrogen (N) fertilizer applications across productivity level management zones (MZs) on continuous corn (Zea Mays L.) fields under dryland and irrigated cropping systems. This study was conducted in northeastern Colorado on a fine-loamy, mixed, superactive, mesic Aridic Haplustalfs soil. Treatments of this study included, four rates of manure application, one uniform application of N fertilizer, one variable rate N application, and an experimental control strip with no treatment. Experimental strips were 4.5 m wide and 540 m long spanned across all MZs, with treatments nested within MZs. First year results of this study shows that variable rate manure applications have the potential to significantly influence grain yields across productivity level management zones. Grain yield was significantly different across productivity zones under irrigated, and under dryland conditions. Manure applications exhibited a strong relationship with grain yield under irrigation (R² = 0.98) and dryland (R² = 0.53) conditions. The study indicates that variable rate manure application has potential to enhance grain yield and may possibly substitute synthetic N fertilizer under conventional and irrigated fields.

Keywords: Corn (Zea mays L.), Precision Manure Management, and Productivity level Management Zones.