Plantas de cobertura e calagem na implantação do sistema plantio direto

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito de plantas de cobertura e da calagem sobre a produtividade da soja e as características químicas do perfil do solo, após implantação do plantio direto. O experimento foi realizado em campo por dois anos, em Latossolo Vermelho-Amarelo. A área era explorada como pastagem há cinco anos. Avaliaram-se três sistemas de cultivo: soja/pousio/soja, soja/Pennisetum glaucum/soja e soja/ Urochloa ruziziensis/soja, com aplicação de calcário à dosagem de 0, 0,5, 1,0 e 2,0 vezes a quantidade necessária para elevar a saturação de bases (V) a 50%, na camada de 0-20 cm. O calcário foi incorporado ao solo, a 20 cm de profundidade, previamente à implantação dos sistemas de cultivo. Aos 490 dias após a calagem, foram coletadas amostras de solo das profundidades de 0-10, 10-20, 20-40 e 40 -60 cm. Avaliaram-se o estado nutricional das plantas, as alterações das características químicas do solo e a produtividade da soja. As plantas de cobertura associadas à calagem promovem melhorias nos parâmetros de acidez do solo -sobretudo quando a dose aplicada é igual ou mais elevada do que a recomendada para V 50% -, e aumentam o teor foliar de P e a produtividade da soja, independentemente da calagem. Quanto maior a dose de calcário, maior é o avanço da frente alcalina no solo e a produtividade de grãos.Termos para indexação: Pennisetum glaucum, Brachiaria ruziziensis, acidez do solo, correção subsuperficial, sistema de produção. Cover crops and liming in the implementation of no-tillage systemAbstract -The objective of this work was to evaluate the effect of cover crops and liming on soybean yield and on soil chemical characteristics of soil profile, after the implementation of no-tillage system. The experiment was carried out in the field, during two years, in a Typical hapludox. The area was explored as pasture for five years. Three cropping systems were evaluated: soybean/fallow/soybean, soybean/Pennisetum glaucum/soybean, and soybean/Urochloa ruziziensis/soybean, with lime application at doses 0, 0.5, 1.0 and 2.0 times the amount required to raise the saturation base (V) to 50% at the 0-20 cm layer. Lime was incorporated into the soil at 20-cm depth before crop system implementation. At 490 days after liming, soil samples were taken from the depths 0-10, 10-20, 20-40, and 40-60 cm. Plant nutritional status, changes in soil chemical characteristics, and soybean yield were evaluated. Cover crops associated with liming improve soil acidity parameters -mainly when the applied dose is equal to or higher than the one recommended for V 50% -, and increase P foliar contents and soybean yield, regardless of lime. The higher the limestone rate, the greater is the move of the alkaline front in soil and the greater is the grain yield.

Enhancing surface liming rate on a no-till cropping system in an oxisol of Southern Brazilian

“…Veronese et al (2012) verified that the higher the rate, the greater the progress of the alkaline front in the soil, and the higher the grain yield even with deep liming. Moreira et al (2017) suggested that applications of limestone in soil up to a rate necessary to achieve 70% of base saturation are not related with micronutrient deficiency in no-till soybeans.…”

Maize productivity cultivated as first crop in succession to different cover crops

“…Among the management practices for the DSS, the choice of the cover crop is noteworthy, because one of the difficulties has been the maintenance of ground cover due to the high rate of decomposition of plant residues. On this aspect, Veronese et al (2012) indicated that grasses as well as millet and species of Urochloa genus show high dry biomass production and more grow durability on the ground. In turn, legumes have the ability to associate with atmospheric nitrogen fixing bacteria due to their rapid rate of decomposition and mineralization, providing considerable amount of nitrogen for subsequent culture (Ferreira et al, 2011).…”

Surface applied lime dynamics and base saturation index in a consolidated no-tillage area

“…The lime application on the soil surface has a significant effect increasing pH, calcium and magnesium content and base saturation, besides reducing potential acidity in the soil surface (Pöttker & Ben 1998;Caires et al, 2015;Veronese et al, 2012;Schoninger et al, 2010) as well as in the subsurface (Diehl et al, 2008).…”