RESUMOFertilidade do solo é a capacidade deste de fornecer nutrientes, em quantidade e proporção adequadas para o desenvolvimento e produtividade das plantas, na ausência de elementos tóxicos. Este conceito, oriundo da teoria mineralista, é amplamente utilizado no mundo. Com a mudança do sistema de cultivo do solo do convencional (SC) para o plantio direto (SPD), é freqüente a obtenção de alta produtividade das culturas no SPD com valores de indicadores da fertilidade considerados inadequados para o crescimento e desenvolvimento das plantas no SC. É possível que a avaliação tradicional e, conseqüentemente, esse conceito não sejam adequados e, ou, suficientes, para expressar a fertilidade percebida pelas plantas em solos cultivados há longo tempo no SPD. Neste trabalho, objetivou-se avaliar a capacidade do conceito mineralista, e de sua avaliação, em expressar a fertilidade percebida por plantas de milho (Zea mays) em solo cultivado por longo período de tempo no SPD com diferentes rotações de culturas. As avaliações, por indicadores da fertilidade do solo e por rendimento de grãos, foram feitas na safra
<p>The application of the principles of thermodynamics and General Systems Theory is responsible for important progress in the study of soil and its fertility, and this application can even improve our understanding of the processes that govern the functioning of soil and determine the magnitude of soil fertility. Consequently, we can improve the evaluation and practices recommended for preserving or improving the soil and its fertility, contributing to sustainable food production. Recalling how the concept and <em>human </em>perception of soil have evolved is fundamental to improve our understanding. Thus, this article aims to encourage people to reflect on the application of the principles of thermodynamics of non-equilibrium and General Systems Theory in studying the soil and its fertility and to participate in constructing a new notion of soil fertility, able to express what is perceived by plants. Several authors in the last century have considered the soil to be an open system; however, this approach is a recent in Brazil. Fertility can be coherently understood as one of the emergent properties of the soil system by applying the principles of thermodynamics of non-equilibrium and General Systems Theory to the study of soil.</p>
Sustainable agricultural systems are necessary to improve soybean [Glycine max (L.) Merr.] seed yield and to increase nutrient use efficiency. Intensification of agricultural systems is an important tool to increase farmers’ profitability in the Cerrado region (Brazil), where soybean is rotated with corn in the same growing season. However, this intensification requires soybean cultivar with short growing periods which is achieved by indeterminate soybean cultivars. There is a lack of information regarding the nutrient uptake by soybean cultivars under intensive agricultural systems in the Cerrado. We sought to investigate soybean biomass production and soybean seed yield of determinate and indeterminate soybean cultivars. We also aimed to quantify the amounts of nutrients taken up by soybean biomass and seeds. Field research was conducted to evaluate 17 soybean cultivars commonly grown by farmers, and we considered the determinate and indeterminate soybean growth habit. Nutrient uptake and aboveground soybean biomass were higher under shorter soybean growth and development cycles. Nitrogen, phosphorus and potassium extraction in modern cultivars was higher than in cultivars used in past decades. Nutrient use efficiency was higher in determinate soybean cultivars than in indeterminate soybean cultivars.
Soybean is the major crop in the Brazilian Cerrado region. Tocantins state has been increasing soybean production mostly into degraded pasture. However, cover crops such as forages crops are important to implement in regional soybean agricultural systems to increase systems resilience due to climate variability. There is a lack of information regarding to agronomic performance of soybean intercropped with cover crops under no-tillage. The experimental design was randomized complete blocks with four replications in factorial 7 × 2. Seven soybean cultivation systems were tested: 1) soybean intercropped with Urochloa brizantha cv. Marandu; 2) soybean intercropped with Urochloa ruziziensis; 3) soybean intercropped with Panicum maximum cv. Mombaça; 4) soybean intercropped with Panicum infestans cv. Massai; 5) soybean intercropped with Pennisetum americanum; 6) soybean followed by Pennisetum americanum; and 7) soybean and fallow. Two soil acidity and amelioration were tested: 1) with lime and gypsum application; 2) without lime and gypsum application. Soybean grain yield, plant height and number of pods per plant were different. Soybean grain yield were higher with lime ad gypsum application. The highest soybean plants height were observed in the treatments where lime and gypsum were applied, and with soybean intercropped with P. maximun and Millet. Soybean number of pods was positively affected P. infestans intercropped with soybean. There was no significant difference among treatments for mass per 100 seeds. Cover crops showed suitable to increase agronomic performance of soybean.
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