Global Maize Project in Brazil: Ponta Grossa, Paraná

Cropping system intensification will be necessary to meet the future demands for corn. The proposed system of Ecological Intensification (EI) seeks cereal production systems that satisfy these future demands while developing cultivation practices with minimum interference to the surrounding environment. A Global Maize Project was established to identify yield gaps between current technology and improved technology aimed at achieving EI. The experiment was first established at Ponta Grossa, Paraná, in May 2011, by seeding winter crops to respective treatment plots. The soil in the area is an Oxisol that has been in a no-till system for six years. The experiment had a split-plot design with the main plots involving three types of management systems and the sub plots being three levels of N input plus a control. Different management systems used were: farmer practice (FP) involving a 2-year complete crop rotation cycle of black oats, corn, wheat, and soybean; FP + silage production; and EI of black oats + forage peas, corn, black oats, and soybean. The EI treatment is planned to occur twice, alternating the crop rotation initiation point to permit the production of corn every summer. The levels of N application for the corn were 70, 140 and 210 kg N/ha, plus a control with no N added.

Dry matter yields of winter crops varied from 3.9 t/ha for black oats to 5.7 t/ha for ryegrass. Up to 140 kg N/ha was applied to the soil for growing winter crops. As mentioned earlier, it was possible to visualize the effect of winter forage peas on summer maize growth, through their addition of N to the soil. Grain yields were significantly higher when maize was cultivated after forage peas, compared to white or black oat. At higher N fertilizer application rates, grain yield averaged 13.3 t/ha. Soil samples were collected to evaluate soil physical properties and are being analyzed. Tissue samples were collected from the summer crop for laboratory analysis.

Results from 2013 showed a positive linear response between maize grain yield and N fertilizer application rates. At the higher N rates, grain yield averaged 11.8 t/ha. No significant difference was observed for grain yield among the types of cover crops grown before maize, although forage peas tended to support higher maize grain yields. Higher N application rates raised the N/S ratio of maize leaves, which correlated well with maize grain yields. No residual effect of N applied to maize was observed on the grain yield of the following wheat crop.