Sobressemeadura de espécies forrageiras em soja para viabilidade do plantio direto e integração lavoura-pecuária no Tocantins

Abstract

The regions Brazilian Cerrado are characterized by high temperatures and rainfall in great intensity in the summer, but with dry winter. These conditions result in major constraints for the sustainability of tillage due to low straw production in the autumn-spring period, combined with rapid decomposition during the rainy season. One way to try to solve these problems is for the intercropping of grain crops with forage species, which has shown promising results, giving sustainability to tillage and can provide fodder for livestock in most lean period in areas characterized with winter dry. However, this technology is new and there is need for studies in the various areas covered by the production system. As such, the objective of chapter I was to evaluate the straw production and the agronomic performance of soybean intercropped with different forage species oversowing, in direct planting. The experiment was in a complete randomized block, with four replications in a factorial arrangement 5 x 2 + 2, being five species forage intercropped with soybean (Urochloa brizantha cv. Marandu; Urochloa ruziziensis; Panicum maximum cv. Mombaça; Panicum infestans cv. Massai and; Pennisetum americanum), in two growing seasons (2013/2014 e 2014/2015), more two treatments witnesses (Pennisetum americanum in succession to soybean cultivation and the traditional soybean cultivation, followed by fallow in winter). Were assessed the soybean yield components and straw productivity of forage. The soybean intercropped with forage species Urochloa ruziziensis, U. brizantha cv. Marandu, Panicum maximum cv. Mombaça and P. infestans cv. Massai in oversowing does not reduce the soybean grain yield. The soybean x Mombasa intercropped increases plant height and soybean grain yield when compared to single soybeans. The Mombasa is more efficient in dry matter accumulation when grown in oversowing in soybeans in autumn/spring compared to other forages. The chapter II to aimed was to evaluate forage production and bromatologic composition of different forage species intercropping with soybean in oversowing system and single crop. The experiment was in a complete randomized block, with four replications in a factorial arrangement 5 x 2 + 1, being five species forage (Urochloa brizantha cv. Marandu; Urochloa ruziziensis; Panicum maximum cv. Mombaça; Panicum infestans cv. Massai e; Pennisetum americanum), in two crop systems (intercropped with soybean and single), more a standard treatment (Pennisetum americanum in succession to soybean cultivation). Were evaluated forage yield components and the chemical composition of the forage species. The species Urochloa ruziziensis, U. brizantha, Panicum maximum and P. infestans have higher production capacity de forage both grown intercropped with soybeans as compared to single Pennisetum americanum. The cultivation of the forages Urochloa ruziziensis, U. brizantha, Panicum maximum and Pennisetum americanum way single, provides higher productivity of forages compared to intercropping with soybean. The forages Urochloa ruziziensis and U. brizantha when sown in intercropping, reveals better nutritional value over the course of the autumn-winter period.