Produção de biomassa e teor de macronutrientes do milheto, feijão-de-porco e guandu-anão em cultivo solteiro e consorciado

Abstract

RESUMOObjetivou-se determinar a produção de biomassa e o teor de macronutrientes do milheto (Pennisetum typhoides (Burm.) Stapf), feijão-de-porco (Canavalia ensiformes (L.) DC.) e guandu-anão (Cajanus cajan (L.) Millsp.) em cultivo solteiro e nos consórcios da gramínea com as leguminosas, visando a produção de palha no sistema plantio direto. O trabalho foi conduzido no campo experimental do Departamento de Agricultura da Universidade Federal de Lavras (Lavras, MG, Brasil). O delineamento foi o de blocos casualizados, com cinco tratamentos e quatro repetições. Apenas o guandu-anão solteiro apresentou menor produção de fitomassa fresca e seca, sendo que os demais tratamentos não diferiram entre si, pelo teste de Tukey a 5% de probabilidade. De forma geral, as leguminosas apresentaram maiores teores de N e Ca e o milheto maiores teores de S. Apenas o feijão-de-porco solteiro apresentou menor teor de P. Os maiores teores de K foram apresentados pelo milheto solteiro e consorciado com as leguminosas e pelo feijão-de-porco em consórcio com milheto. Os menores teores de Mg foram verificados para o guandu-anão.Termos para indexação: plantio direto, adubação verde, reciclagem de nutrientes. ABSTRACTThe object of this work was to evaluate the biomass production and the macronutrients quantity of millet (Pennisetum typhoides (Burm.) Stapf), jack bean (Canavalia ensiformes (L.) DC.), guandu (Cajanus cajan, (L.) Millsp.) dwarf cultivar, and the millet with leguminous consortiums to straw production in no-tillage system. The experiment was carried in experimental area at Agriculture Department of the Federal University of Lavras (Lavras, Minas Gerais state, Brazil). The experimental design was randomized blocks, with five treatments and four replications. For biomass production, only the guandu presented smaller fresh and dry biomass yield than the other treatments. In general, the leguminous presented the greatest N and Ca quantities and millet the greatest quantities of S. Only jack bean presented minor P quantity. For K the greatest quantities were verified for single milett and its incropping with leguminous and jack bean in intercroppin with millet. The minor quantities of Mg were observed for guandu.Index terms: no-tillage, green manuring, nutrients recycle. INTRODUÇÃOCom a expansão do plantio direto, a experiência dos produtores e as pesquisas realizadas, constatou-se que a rotação/sucessão de culturas era fundamental para a viabilidade do sistema, devendo ser baseada, entre outros fatores na utilização do solo, tanto química quanto fisicamente, devido às diferenças de exigência nutricional e exploração pelo sistema radicular das diferentes espécies; e no potencial de produção de palha das culturas, sejam elas comerciais, aproveitando os restos culturais, ou semeadas exclusivamente para este fim. Na Região Sul, o inverno chuvoso permite a implantação de cultivos de inverno para a produção exclusiva de palha ou a produção de grãos, com alta quantidade de restos culturais como o trigo, centeio, cevada e aveia. Além des...

Cycling of nutrients and silicon in pigeonpea and pearl millet monoculture and intercropping

“…The differences in these concentrations may be explained by the different growing seasons and by factors related to the soil fertility of each location. As reported by Teixeira et al (2005), the variability in nutrient concentrations within the same species is mostly due to differences in the soil fertility of the study locations. The concentration of all macronutrients declined over time, accompanying the results of the SDM (Figures 2a and 3), with the exception of Si.…”

“…Teixeira et al (2005) observed lower values of N, P, K, Ca, Mg, and S in pigeonpea and pearl millet SDM in monoculture. In the intercrop of these species, the authors obtained values near those found in this study.…”

“…Thus, as the SDM degraded, the Si concentration in the plant residue increased because the more soluble elements were released (Figure 3) with the remaining Si compounds, which have lower solubility (Fernandez et al, 2009 Greater N and Ca concentration in pigeonpea SDM, greater Mg concentration in pearl millet SDM and the large reduction of K concentrations in the three plant SDM were evident (Figure 3a,c,d). Teixeira et al (2005), studying SDM production and macronutrient concentration in pearl millet, jack bean and pigeonpea, in monoculture and intercropping, also observed greater N and Ca concentrations in the legumes.…”

“…However, it promotes nutrient recycling through nutrient uptake from deeper soil layers and adds N to the system by means of biological fixation (Teixeira et al, 2005;Salmi et al, 2006). In addition, Andrade et al (2009) reported that soil macroporosity in the 0-10 cm layer was greater under pigeonpea than pearl millet.…”

“…Intercropping of legumes and grasses is an attempt to unite the individual benefits of each species, to attenuate the problem of low SDM production and persistence, and of soil compaction and N deficiency in the initial stages of development of successive crops, as well as to recycle the nutrients with high mobility in the soil (Aita & Giacomini, 2003;Perin et al, 2004;Teixeira et al, 2005;Calvo et al, 2010), notably N in the form of nitrate, and increase the supply of this nutrient in the soil by biological fixation by the legume. In addition, normally, the content of nutrients in the SDM, the speed of decomposition and nutrient release from these plants varies between grasses and legumes (Boer et al, 2007), which may also be an advantage in intercropping.…”