Crescimento e nutrição mineral de capim-braquiária

Abstract

423Crescimento e nutrição mineral de capim-braquiária

Growth and mineral nutrition of Solanum americanum

“…After this period, there was a reduction of total dry matter accumulation due to plant senescence. Growing under same conditions, D. tortuosum, E. heterophylla, H. suaveolens, I. nil, I. quamoclit, R. brasiliensis and S. obtusifolia showed the most dry matter accumulation at 161,116,145,123,146,147 and 147 DAE, as observed by Gravena et al, (2002), Bianco et al (2004b) It was ascertained considerable dry matter accumulation from 63 to 119 DAE ( Figure 1A). During this period, high dry matter increase occurred mainly as a function of accumulation in stems ( Figure 1B).…”

“…Comparing the results of this research with those obtained on broadleaved weeds, it may be evidenced that, in the PMtAM, S. americanum accumulated more N, P, K, Ca, Mg and S than D. tortuosum (Bianco et al, 2004b), E. heterophylla (Bianco et al, 2007), I. nil (Duarte et al, 2008) and I. quamoclit (Carvalho et al, 2009), R. brasiliensis (Pedrinho Júnior et al, 2004) and S. obtusifolia (Bianco et al, 2008). Therefore, S. americanum was more demanding for macronutrients than these weeds.…”

“…The highest rates of N, P and K were observed at 21 DAE, whereas the Ca, Mg and S highest rates were verified at 49, 91 and 147 DAE, respectively. When studying mineral nutrition in broadleaved weeds, Bianco et al (2004b) Nevertheless, a great accumulation of P was verified from 77 to 147 DAE, while it was observed from 77 to 119 DAE for Ca and from 91 to 133 DAE for S ( Figures 2B, 2D and 2F). There was a real accumulation of 461.04 mg Growth and mineral nutrition of Solanum americanum of P per plant at 147 DAE, while 3,239.26 mg of Ca were accumulated per plant at 119 DAE and 425.32 mg of S were accumulated per plant at 133 DAE.…”

“…Due to this fact, important studies have already been conducted for Senna obtusifolia (Erasmo et al, 2000), Urena lobata (Souza Filho et al, 2000), Cardiospermum halicacabum (Brighenti et al, 2003), Richardia brasiliensis competing with Glycine max (Pedrinho Júnior et al, 2004), Quercus petraea, Fagus sylvatica, Acer pseudoplatanus (Kazda et al 2004), Brachiaria decumbens (Bianco et al, 2005), Euphorbia heterophylla competing with G. max (Bianco et al, 2007), Brachiaria plantaginea competing with Zea mays , Ipomoea nil (Duarte et al, 2008) and Ipomoea quamoclit (Carvalho et al, 2009).…”

Produtividade e teor de nutrientes do milho em consórcio com braquiária

“…O aumento da densidade de braquiária reduziu linearmente o teor de fósforo (P) nas folhas de milho, sendo que o incremento de cada planta forrageira promove redução de 0,0017dag kg -1 da variável (Figura 2b). O crescimento da U. brizantha é caracterizado por um maior incremento inicial do sistema radicular, visando a melhor fixação da planta no solo e rápido acúmulo de nutrientes pelas raízes, o que favorece na competição pelo fósforo do solo com as culturas (BIANCO et al, 2005). Dessa maneira, espera-se que quanto maior o número de plantas de braquiária próximos à planta de milho, menor será o conteúdo de fósforo nas folhas da cultura.…”