Global Maize Project in Brazil: Itiquira, Mato Grosso

IPNI-2009-BRA-GM18

27 Mar 2014

2013 Annual Interpretive Summary


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 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 2009 at Itiquira, Mato Grosso on 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 rates 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 rates of N application 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. Soybeans responded to N previously applied to corn, showing that for high soybean yields, biological fixation of N may not be sufficient for maximum yields. Recent data shows 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 the first maize crop.

Results from 2013 were similar to previous years, i.e., both maize crops responded positively to increasing N rates. Soybean yield responded to N rates applied to the previous maize crop. The EI system produced less grain for the four previous years, compared to the FP. This might be due to the use of lower rates of N fertilizer in the first three years of the experiment. The N application rate was increased in the fourth year, so an increase in yield in the EI system is likely in future years.