EFEITO RESIDUAL DE CORRETIVOS DO SOLO ESTIMADOS POR DIFERENTES MÉTODOS EM NEOSSOLO QUARTZARÊNICO ÓRTICO

Abstract

This work aimed to evaluate soybean production in fragile soils, under different methods of determining the need for soil correction. The experiment was installed in the city of Rio Verde – GO, under a randomized block design, with four replications and six forms of soil correction: 1 – without correction; 2 – liming, with 4.8 ton ha-1 of limestone; 3 – gypsum, with 700 kg ha-1; 4 – liming + plastering (treatments 2 + 3); 5 – liming, with a dose of 6.9 ton ha-1; 6 – liming + gypsum with 2.7 ton ha-1 of limestone and 5.94 ton ha-1 of gypsum. The limestone (39% CaO; 6% MgO and 75% PRNT) and gypsum (25% CaO) correctives in the treatment doses were applied by broadcast, incorporated at a depth of 40 cm, and after 18 days of incorporation samples composed of soil at depths of 0 – 0.05; 0.05 - 0.1; 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 – 0.6 m, and from this date onwards, new samples were taken every 30 days until harvest, totaling 4 samples. The contents of Ca, Mg, K, P (Mehlich I), Al, H+Al, pH (CaCl2) and sulfate were evaluated. Plant sampling was carried out in the two central lines of the plot, taking 12 m of the useful plot. Then, the yield and the weight of a thousand grains were estimated. The data obtained from the soil analysis were submitted to analysis of variance and multivariate regression using the R software, and the production data to the analysis of variance and mean test (at 5% probability) using the SISVAR software. In general, as it is a low-resilience soil, in sandy soil the acidification caused by soybean cultivation generates a demand for correction for the next crop, unless a high dose is added for a long residual effect. Treatments (C), (CG) and (CCTC), both with limestone, were more effective in controlling the acidity front and pH increase, with treatment (C) having the highest productivity.