Nitrogen management strategies for maize production systems: Experimental data and crop modeling

Maize (Zea mays L.) is an important crop among Brazilian smallholder farmers, who are also responsible for 40% of the poultry and egg production in the country. Although poultry litter is considered a potential pollutant, if properly stabilized and distributed in the field it can be used as a source of nitrogen for maize production. In this study, the response of maize to mineral fertilizer and poultry litter as source of nitrogen was evaluated and the results were then used to parameterize a processbased model. For both sources of nitrogen used in the second trial the average observed yield was higher than the average yield obtained by farmers during the preceding years, indicating that there is a potential for improvement of maize yield in the region. A rate of 195 kg ha^-1of nitrogen as poultry litter provided a slightly higher yield than a rate of 145 kg ha^-1of nitrogen as mineral fertilizer. After adjustments in the CSM-CERES-Maize cultivar-specific coefficients the model satisfactorily simulated maize anthesis, physiological maturity and yield. Poultry litter has the potential to be an alternative source of nitrogen for maize production in smallholder farms. The CSM-CERES-Maize model properly simulated maize growth, development and yield for both, mineral fertilizer and poultry litter sources of nitrogen.