Produtividade de milho e gramíneas tropicais perenes no outono - inverno em sucessão a soja

Abstract

Goal of this work was to assess species and cultivars of tropical Brachiaria and Panicum forage grasses intercropped with corn, using or not growth suppression through underdose of nicosulphuron herbicide in order to determine the best alternatives for corn and soybean grains production, as well as forage biomass and above-ground dry matter to improve no-till systems. The trial was carried out at the experimental station of the agriculture college of UFGD, in Dourados, Mato Grosso do Sul State between 2014 and 2015. To evaluate corn performance, experimental design was randomized blocks under factorial design (5x2+1) x2 being, single corn and corn intercropped with five grasses, submitted to two levels of suppression with herbicides. Four repetitions were used. For evaluating soybeans, experimental design was randomized blocks with 16 treatments and four repetitions each. Treatments corresponded no-till cultivation of soybeans over crop residues of Brachiaria brizantha cvs. Xaraés, Piatã and Marandu; Brachiaria ruziziensis and Panicum maximum cv. Mombaça, using three cropping systems: single forage; forage intercropped with corn using or not nicosulphuron herbicide for suppressing forage growth. Results show that Panicum maximum cv. Mombaça intercropped with corn produced the highest forage but the least corn grains yield. Brachiaria brizantha cv. Piatã had an average forage yield while causing the least decrease in corn grain yield. Therefore, Fall-Winter corn cultivation intercropped with perennial forage grasses can be a good alternative for establishing/recovering pastures while producing corn grains and crop residues for subsequent soybeans no-till cultivation. Soybeans grain yield was the lowest when cultivated over single corn crop residues. Highest soybeans grain yield was obtained over single Panicum maximum cv. Mombaça, followed by single B. brizantha cv. Xaraes and Marandu in the two experimental cycles and suppressed B. Ruziziensis intercropped with corn in the 2014/2015 season.