A study was carried out to evaluate the effects of liming on the yield of four early varieties of soybeans. The experiment was conducted on a Red Yellow Podzolic soil during three years, in which the last two years the residual effect of liming was studied. A split plot design was used, in which the main plots consisted of liming (0, 4, 8 and 12 t/ha) and the sub-plots the early varieties (IAC-13, IAS-5, BR-4 and BR-6). The results showed that independent of varieties, liming increased the soybean yield, decreased the oil content and increased the protein content. Concerning the average of three years, independent of liming levels, the variety BR-4 produced the greatest quantity of oil and protein (444 and 709 kg/ha). The ratio protein/oil was similar among the four cultivars studied.
soybeans; Glycine max; liming; oil; protein; variety