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) was established to identify gaps in yield between current technology and improved technology aimed at achieving EI. The experiment was initiated in November 2009 at Itiquira, Mato Grosso in an Oxisol that has been under cultivation for 20 years. The experiment has a split-plot design with main plots involving three types of cultivation systems and the sub plots being three levels of 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 levels of N input were 50, 100 and 150 kg N/ha for the first corn crop (summer crop) or 30, 60 and 90 kg N/ha for the second corn crop, plus a control with no N added in both cases.

The results to date indicate that there were good responses to N in both maize crops, which positively influenced maize yields and total N uptake. The addition of N positively impacted the dry matter yield of the forage grass cultivated with corn. Soybean grain yield was similar if cultivated after corn second crop + forage or cultivated only after corn. Soybean crop responded to N previously applied to corn showing that for high soybean yields N biological fixation may not be enough. Latest data have shown a depression in grain yield and biomass of maize second crop when cultivated after maize first crop + forage, likely due to the high N exportation from first maize crop. This is a long-term project intended to influence current opinions on how to best manage cereal production in the region. IPNI-18