Ecological Intensification On Maize Cropping Systems in the Cerrado of Brazil.

Ecological intensification of cropping systems is required to fulfill the future demand for grain production. This concept needs to accommodate grain cropping systems for food into acceptable standards of low environmental interference. In this path, a net of field trials has been carried on worldwide to identify gaps between yield in current maize cropping systems and attainable yield with the intensification of crop management under field conditions (The Global Maize Project). In Brazil, a field trial located in Itiquira, MT, has generated data for four seasons studying a local variation of the maize cropping system (soybean/maize) where four different crops are grown within a crop rotation sequence of three years (soybean/maize+brachiaria grass/soybean/sunn hemp/maize+brachiaria grass), as well as interacting with different nitrogen rates (0 to 150 kg N ha^-1). So far, maize yield has presented positive linear response to N additions whether as first crop or as a second crop. The association of brachiaria grass with maize has promoted contrasting effect along the years, but positive yield increase has been observed in most of the seasons. The N addition to the cropping systems is also promoting positive yield response of the soybean grown after maize, according to N rates applied. Nitrogen balance in high intensive cropping systems, as the one in test, is likely to be the key for increasing grain yield. Results are not conclusive in this long term project but for sure have shown some important aspects of the ecological intensification for local farmers.