On-farm starter fertilizer response in no-till corn

Even though recent experiments in the southern Corn Belt have shown that corn (Zea mays L.) yield responses to starter fertilizer are fairly common in no-till management systems, few producers in this region use starter fertilizer. Producer skepticism about the applicability of small-plot research to production situations Is one reason for this lack of adaption. Several experiments have suggested that N is the most important nutrient for producing yield responses, while others have indicated that P is important its well. The objective of this research was to (i) validate at a held scale no-till corn yield and economic response to starter fertilizer and (ii) determine the relative importance of N and P in producing this yield response. During a 3-yr period, six replicated strip trials were conducted in production cornfields comparing no starter to three categories of starter fertilizer: traditional low N/high P2O5, medium N/medium P2O5, and N-only. Significant positive yield responses to starter fertilizers were observed in all six experiments. Yield differences between the three categories of starter fertilizer were minimal, and not statistically significant when averaged across locations. The average of all starter categories and experiment locations showed that starter fertilizer increased yield by 13 bu/acre. Use of starter fertilizer for no-till corn appears to be a profitable practice under production-field conditions in the southern Corn Pelt. Nitrogen-only starter was the most profitable because it had the lowest material cost and produced the same yield as the P-containing starters.