Fitossociologia de plantas daninhas em sistemas de integração de sorgo com braquiária sob diferentes formas de implantação da pastagem

Abstract

-The objective of this study was to evaluate the effect of the sowing modality of Brachiaria brizantha cv. Xaraés on the weed community and productivity of Sorghum bicolor cv. BRS 160 under the agricultural cattle-raising integration system. The treatments were constituted by sorghum forage intercropped with B. brizantha throwing-sown with light incorporation and without incorporation; sorghum forage intercropped with B. brizantha sown in a single row and in two rows in the leading row of the annual culture; and witnesses represented by the sorghum monocultures, with and without atrazine application, and of brachiaria. Major production of weed dry mass was observed in the monoculture treatments, with the species Digitaria horizontalis presenting the highest importance value and widest ground cover. For the intercropping cultivations,

Seleção de cultivares de sorgo e braquiária em consórcio para produção de grãos e palhada

“…Destaca-se que a determinação desta variável foi realizada aos 131 dias após a colheita do sorgo, ou seja, próximo ao período de implantação da soja. A maior permanência da massa seca na superfície do solo na fase inicial de desenvolvimento da cultura propicia a proteção do solo contra erosão, visto que nesta fase a soja não possibilita uma cobertura efetiva do solo, além de exercer supressão na emergência das ervas daninhas (MENEZES; LEANDRO, 2004;KLIEMANN;BRAZ;SILVEIRA, 2006;MACHADO et al, 2011).…”

“…O consórcio de sorgo com Brachiaria brizantha cv. Marandu tem-se mostrado como prática viável de cultivo agrícola (MELLO et al, 2004), além do fato de que o manejo de ervas daninhas na cultura em sucessão é facilitado pela produção de palhada de sorgo (SOUZA; SOUZA; PASQUAL, 1999) e Brachiaria brizantha (MACHADO et al, 2011) na superfície do solo.…”

Dessecação da Brachiaria ruziziensis com paraquat antes da semeadura da soja

“…2007, Borghi et al, 2008Castro et al, 2011;Machado et al, 2011;Ikeda et al, 2013). Este fato demonstra a possibilidade de seleção de espécies adaptadas ao sistema de integração agricultura-pecuária.…”

Phytosociology in Degraded and Renewed Pastures in Agrosilvopastoral Systems

“…This demonstrates the good establishment of this grass and its efficiency in the inhibition of weeds, resulting in productive pastures. The fast establishment characteristic gives competitive advantages to B. brizantha in relation to weeds (Machado et al, 2011). The possible existence of allelopathic compounds emitted by B. brizantha may also have helped the development of this forage species over some weeds (Martins et al, 2006).…”

“…This fact may be related to the photosynthetic metabolism of each cultivated forage species, since B. brizantha plants present a C4 metabolism, which expresses high growth capacity under conditions of high temperature and luminosity, whereas M. axillare plants have a C3 metabolism and saturate with high luminosity indices and have their development reduced by high temperatures (Taiz and Zeiger, 2013). Moreover, it is known that forage grasses from the Brachiaria genus have high competitive capacity towards other species (Machado et al, 2011). Since the study deals with system implantation, the shading provided by the different spacings was not relevant, because eucalyptus plants were still small (approximately 50 cm); however, in shaded systems, the growth of perennial horsegram may be different due to C3 metabolism, with greater efficiency in the use of light energy (Taiz and Zeiger, 2013).…”