Resumo -O gesso agrícola pode ser utilizado como fonte de enxofre, desta forma, melhorando a nutrição e promovendo ganhos na produtividade da cultura da soja em sistema de plantio direto. Objetivou-se com este trabalho avaliar os efeitos do enxofre (S) aplicados na forma de gesso agrícola na cultura da soja em sistema de plantio direto com e sem adubação potássica. O experimento foi conduzido no município de Guairá-SP em solo da classe LATOSSOLO VERMELHO Eutrófico. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 2 x 5, com quatro repetições. Os tratamentos foram obtidos pela combinação de dois níveis de K (0 e 60 kg ha -1 de K 2 O), fonte cloreto de potássio; e cinco doses de enxofre (0, 30, 60, 90 e 120 kg ha -1 de S), fonte gesso agrícola. Foram avaliados os teores foliares de potássio, cálcio e enxofre, além da produção de grãos e o teor de óleo presente nos grãos. O enxofre aplicado no solo melhora o estado nutricional da cultura da soja aumentando os teores de potássio, cálcio e enxofre, sem influenciar a produtividade de grãos, independente da adubação potássica. A aplicação de enxofre no solo aumenta o teor de óleo nos grãos da soja com ou sem adubação potássica.Palavras-chave -Enxofre. Nutrição de plantas. Sistema conservacionista. Abstract -The gypsum can be used as a sulfur source, thereby improving nutrition and promoting gains in yield of soybeans in no-tillage system. The objective of this study was to evaluate the effects of sulfur applied as gypsum in the soybean culture under the no-tillage system with and without potassium fertilization. The experiment was conducted in the city of Guaíra-SP in an OXISOL. The experimental design used was randomized blocks in factorial scheme 2 x 5 with four replications. The treatments were obtained by combining two levels of K (0 and 60 kg ha -1 K 2 O), applied as potassium chloride, and five doses of sulfur (0, 30, 60, 90 and 120 kg ha -1 S) applied in the form of gypsum. Foliar potassium, calcium and sulfur, in addition to grain yield and oil content in the grains were evaluated. It was observed that the application of sulfur in the soil improved the nutritional status of soybean in potassium, calcium and sulfur, without affecting grain yield, independent of potassium fertilization. The presence of sulfur in the soil increased the oil content in soybean grain with or without potassium fertilization.

Due to the intensification of production in irrigated areas, maize hasbeen sown in winter, enabling three seasons in one agricultural year. The objective of this study was to evaluate the agronomic performance of maize under irrigation and cultivated in winter under different plant arrangements (single and doublerow) under top-dressing nitrogen doses. The experimental design used was in randomized blocks in a split-plot scheme, with four replicates. Plots were formed by sowing systems single and double rows and subplots were formed by four top-dressing N doses: 0 kg ha-1 of N; 80 kg ha-1 of N with single application in phenological stage V3; 160 kg ha-1 of N with application of 80 kg ha-1 in V3 and V6, and 240 kg ha-1 of N with application of 80 kg ha-1 in stages V3, V6 and V8. The single-row sowing system led to higher grain yield compared to maize grown in the double-row system. Maize grain yield showed progressive linear increments with increasing top-dressing N doses, reaching 11,089 kg ha-1 of grains with the maximum studied dose of 240 kg ha-1 of N. Sowing systems in single and double rows do not differ with respect to the use of top-dressing N.