Aplicação de gesso em lavoura cafeeira e eficiência para o cultivo de feijoeiro: distribuição de íons no perfil e especiação na solução do solo

Abstract

Brazilian agriculture has advanced to the thick areas, where Latosols predominate. Soils that have low natural fertility and high fertility, however, have a high degree of fertility with the physical characteristics suitable for mechanization. The use of agriculture has been showing good results, in the precision of the accuracy and availability of nutrients in depth. They were: i) to evaluate the mobility and effects of increasing gypsum on pH, calcium conductivity (EC) and calcium (Ca), magnesium (Mg), potential content (K) and sulfur (S) in the effluent collected in leaching columns; ii) evaluate the availability of Ca, Mg, K and S in soil samples, in a column of up to 100 cm; iii) to evaluate the effect of gypsum doses on bean cultivation and iv) to evaluate an ionic specification of the soil solution in a soil profile in a coffee plantation area 76 months after the application of high application rates. Part of the work carried out in a forest house, where it was demonstrated in a Latosol prepared in columns with 10, 2, 40, 60 and 100 cm in depth. On the nearby surface, doses of gypsum equivalent to 0, 1.5, 3, 7, 11 and 15 t ha-1 will be applied. Five collections were carried out, where 10 EC, pH and Ca, Mg, K and S contents were analyzed. At the end of the leaching, the same elements were not found alone and bean was then cultivated. The nutritional status of shoots and grains, as well as root distribution. The study in a coffee area was carried out in a coffee plantation, cultivated in 4 doses of gypsum (0, 7, 14 and 56 t ha-1). Soil samples were collected at 76 months after treatment application, at the following depths: 15-25, 35-45, 75-85, 125-135, 165-185, 225-245. Soil solutions were extracted, in which the chemical speciation of Ca, Mg, K and sulfate was evaluated. In the columns, the EC decreased with the increase of applied accumulated water and the pH values were not influenced. The Ca and S contents increased along the entire length of the column, as the gypsum doses were increased, until close to 60 cm. Mg was the most leached cation with increasing gypsum doses. K was leached up to 100 cm. The available levels of Ca, Mg, K and SO42- increased in the deeper layers, according to the doses. The Ca and S contents, both in the shoot and in the bean grains, were higher with the increase of the applied dose, while the Mg and K contents decreased. The dry matter production of the bean shoot showed a quadratic behavior, increasing up to the rate of 10.48 t ha-1. The bean yield increased linearly up to the rate of 15 t ha-1. Most of the elements evaluated in the field study are found free in the solution.