Fertilizer recommendations for maize production in the south Sudan and Sudano-guinean zones of Benin

Abstract

The present study aims to determine fertilizer (N-P-K) recommendations for maize (Zea mays L.) on Acrisols (south Benin) and Ferric and Plintic Luvisols (centre Benin). Two years experiment (2011 and 2012) were conducted at Dogbo and Allada districts (southern) and Dassa (centre Benin). Six on-farm experiments were carried out in order to validate fertilizer rates simulated by DSSAT simulation model. The experimental design in each farmers' field was a completely randomized bloc with four replications and ten N-P-K rates: 0-0-0 (control), 44-15-17.5 (standard fertilizer recommendation for maize), 80-30-40, 80-15-40, 80-30-25, 80-30-0, 69-30-40, 92-30-40, 69-15-25 and 46-15-25 kg ha-1. The optimum N, P and K rates in both research sites were: 80.5 kg N ha-1; 22.5 kg P ha-1 and 20 kg K ha-1. Treatments 44-15-17.5 and 46-15-25 showed the lowest grain and stover yields compared to the other treatments. The observed maize grain yields were highly correlated with the estimated grain yields (R2 values varied between 80 and 91% for growing season 2011 and between 68 and 94% for growing season of 2012). The NRSME values varied between 12.54 and 22.56% (for growing season of 2011) and between 13.09 and 24.13% (for growing season of 2012). The economic strategies analysis for pass 32 years (1980 to 2012) showed that N-P-K rates 80-30-25 (site of Dogbo), 80-15-40 (site of Allada) and 80.5-22.5-20 (site of Dassa) were the best fertilizer recommendations as they presented the highest grain yields and the best return to investment per hectare.