Nitrogen management strategies for smallholder maize production systems: Yield and profitability variability

Maize (Zea mays L.) production requires large amounts of nitrogen (N) that directly affect production cost. Poultry litter can be used as an alternative source of N. To optimize its use, poultry litter requires technical and economic feasibility analyses. Crop simulation models have proven to be efficient tools to support this type of research. The objectives of this study were to determine yield and net return of maize production fertilized with both mineral fertilizer and poultry litter. High inter-annual variation was observed in simulated yield for all fertilization strategies evaluated. The higher the mineral N rate, the higher the yield. Among the treatments fertilized with poultry litter the highest yield was obtained with a rate equivalent to 240 kg ha^-1of N. The trend of the economic net return for the different rates of mineral fertilizers was in the opposite direction of the trend in yield, i.e., the higher the rate of mineral fertilizer, the lower the economic return. Among the poultry litter fertilization strategies, the average economic net return increased up to a rate equivalent to 210 kg ha^-1of N, decreasing for higher rates. Poultry litter rates equivalent to 120 to 300 kg ha^-1of N, economically exceeded all the mineral fertilization strategies that were evaluated. Among all sources and rates, the highest net return was obtained for a rate of 210 kg ha^-1of N as poultry litter. Higher rates provided a lower net return and increased the likelihood of nitrate leaching.