Dissolução, doses de calcário, métodos e disponibilidade de nutrientes em cinco solos do Tocantins

Abstract

In the fast occupation of Tocantins soils by soybean cultivation, it has been observed in high doses of limestone and in a period very close to the plan. Insufficient time to dissolve or a high dose of the corrective promotes a chemical imbalance in the soil, with consequent reduction in the availability of most nutrients. Thus, the effect of doses and the incubation times of the acidity corrector and the chemical attributes of Tocantins soils were evaluated. The work was conducted in a completely randomized design with 10 treatments obtained in a 5X2 factorial scheme, combining five doses of limestone (0, 2.0, 4.0, 6.0 and 8.0 t ha-1) and two treatments Incubation periods (15 and 60 days). The soils used in the incubation were: Petric Plinthsol, clay texture (Buritirana); Red Latosol, clayey texture (Buritirana); Red-Yellow Latosol, medium texture (Gurupi); Quartzarenic Neosol, sandy texture (Gurupi) and Quartzarenic Neosol, sandy texture (Guaraí). The content of aluminum and potential acid (H+Al) were reduced and calcium and magnesium contents were increased with increasing limestone dose applied. For the construction of the fertility of the Petric Plinthsol (Buritirana) and Red Latosol (Buritirana), 6 t ha-1 are required to reach ideal values of Ca, Mg, Al and pH at 60 days after application. At 15 days this construction is achieved at a dose of 8 t ha-1. The construction of the fertility of the Red- Yellow Latosol (Gurupi), was dosed with a dose of 4 t ha-1 at 60 days. For the Quartzarenic Neosol of Guaraí and Gurupi, an application of 2 t ha-1 of the soil acidity corrector to neutralize the exchangeable acidity and raise the pH value to 60 days after application is not enough for a fertility construction in calcium and magnesium.