Global Maize Project in Brazil: Itiquira, Mato Grosso

Cropping system intensification will be necessary to meet the future demand for corn (maize). Ecological Intensification (EI) seeks cereal production systems that satisfy future demands, while developing cultivation practices with minimum interference to the surrounding environment. A Global Maize Project (GMP) site was established to identify gaps in yield between the current technology and improved technology aimed at achieving EI. This experiment was initiated in November 2009 at Itiquira, Mato Grosso on an Oxisol that has been under cultivation for 20 years. The experiment has a split-plot design with the main plots involving three types of cultivation systems and the sub plots having three levels of nitrogen (N) input plus a control. The types of cultivation being evaluated are: farmer practice (FP) of soybean followed by corn; FP + a forage crop (Brachiaria decumbens) in the winter; and EI involving a 3-year complete crop rotation cycle of soybean, corn (second crop), forage, soybean, crotalaria, regular corn, and forage. The EI treatment occurs three times, alternating the initiation point of the crop rotation to permit the production of corn every summer. The application rates of N fertilizer were 210 kg N/ha for the first corn crop (summer crop) or 40, 80, and 120 kg N/ha for the second corn crop, plus a control with no N added in both cases.

The results from last season indicated a diminishing returns response to N, which positively influenced maize yields. Maize yield with EI treatment averaged 9.6 t/ha, while FP yield was 8.3 t/ha. One explanation for this difference is the fact that no starter N (30 kg/ha) was applied to FP and FP+CC treatments, but only to EI treatment. Other than that case, all treatments received equal broadcast N rates. Brachiaria grass is no longer being intercropped with maize and the winter legume is now pigeonpea, which is in substitution for crotalaria. Soybean also seemed to benefit from the EI treament yielding 5.2 t/ha, while in FP yielded 4.9 t/ha.

Changes made in the project did promote a better development of crops under EI. This is a long-term project intended to influence current opinions on how to best manage cereal production in the region.