GYPSUM IN MANAGEMENT SYSTEMS AND SOYBEAN PRODUCTIVITY IN SOUTHWEST REGION OF GOIAS

The tilling of areas in no-tillage to several years and the use of gypsum practices are observed among the farmers in, southwestern Goias. This study was carried out to evaluate the effect of gypsum rates (0, 1, 2, 4 e 6 Mg ha(-1)) on some chemical attributes in the soil's depth and in soybean yield in area under long-term no-till, with and without tillage. A complete randomized block scheme with a split-split-plot design with four replicates was used. The at-ea has been conducted under no-till for several years in a dystrophic Clay Red-Yellow Latosol, in southwestern Goias, where calcium, magnesium, potassium and sulphate contents and effective cation exchange capacity Were determined in the 0-5, 5-10, 10-20 and 20-40 cm layers. A higher concentration of cations and sulphate was observed in the 0-5 cm. layer under no-tillage without revolving while the no-tillage with revolving, the sulphate concentrated in the 2040 cm. layer. Although soybean yields were higher under no-till without revolving they were not affected by gypsum rates.