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Resumo -O objetivo deste trabalho foi avaliar a produção de matéria seca e o controle de plantas daninhas por espécies de leguminosas consorciadas com cana-de-açúcar, em cultivo orgânico. As espécies leguminosas Arachis pintoi, Cajanus cajan, Calopogonium mucunoides, Crotalaria anagyroides, Crotalaria juncea e Stylosanthes 'Campo Grande' foram semeadas em novembro de 2012, nas entrelinhas da cana-de-açúcar. O delineamento experimental em blocos ao acaso foi utilizado com quatro repetições e dois controles -um tratamento capinado e outro sem capinar. A massa de matéria seca das leguminosas foi avaliada aos 142 dias após a semeadura (DAS), e a massa de matéria seca de plantas daninhas, aos 29, 85 e 142 DAS. A massa de matéria seca de plantas daninhas foi inferior à da testemunha em todas as épocas amostradas. A produção de massa de matéria seca das leguminosas no consórcio foi baixa. As espécies Crotalaria juncea, Cajanus cajan e Calopogonium mucunoides produziram massa de matéria seca superior à das espécies Arachis pintoi e Stylosanthes 'Campo Grande'. A produtividade de colmos da cana-de-açúcar não foi afetada pelo consórcio. O consórcio entre cana-de-açúcar orgânica e leguminosas com semeadura tardia, para adubação verde, é eficiente no controle de plantas daninhas.Termos para indexação: Saccharum, açúcar orgânico, adubo verde, manejo cultural, planta de cobertura. Dry matter production and weed control by intercropped legumes with sugarcane in organic croppingAbstract -The objective of this work was to evaluate dry matter production and weed control by intercropped legumes with sugarcane, in organic cropping. The legume species Arachis pintoi, Cajanus cajan, Calopogonium mucunoides, Crotalaria anagyroides, Crotalaria juncea, and Stylosanthes 'Campo Grande' were sown on November 2012 in the inter-rows of sugarcane. A randomized complete block experimental design was used with four replicates and two controls -a weeded treatment and an unweeded one. Legume dry matter was evaluated 142 days after sowing (DAS), and the weed dry matter, at 29, 85, and 142 DAS. Weed dry matter was lower than that of the control in all sampling periods. The production of legume dry matter was low in intercropping. The species Crotalaria juncea, Cajanus cajan, and Calopogonium mucunoides produced higher dry matter than the species Arachis pintoi and Stylosanthes 'Campo Grande'. Stalk yield of sugarcane was not affected by intercropping. The intercropping of organic sugarcane and legumes in late sowing, for green manure, is efficient for weed control.

The aim of this study was to evaluate the soil acidity correction and the grain yield responses for the lime application in different granulometric particles. The limestone particle sizes incorporated into the distroferric red Oxisol were: 0.20 mm to 0.30 mm; 0.30 mm to 0.56 mm; 0.56 mm to 0.82 mm and 0.82 mm to 2.00 mm, at doses of 1.3 t ha-1; 2.6 t ha-1; 3.9 t ha-1 and 6.6 t ha-1 respectively, and a control respectively, and a control (no lime incorporation in the soil). The soil chemical characteristics pH, H+Al3+, Al3+, Ca2+ e Mg2+ were evaluated at 6 months and 18 months after the lime application. The corn yields were evaluated during the 2008/2009 and 2009/2010 crop years. Higher limestone contents and lower particle size resulted in the same effect on soil acidity correction, reducing Al3+ and increasing Ca2+ and Mg2+ in the soil when the 0.30 mm limestone was incorporated, with residual effect at 18 months. Highest corn yield was obtained when the 0.82 mm to 2.00 mm particle size was incorporated in the first crop year, when compared to the lowest limestone particle size used.

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Although the benefits of gypsum for subsoil conditioning are known, there is still a lack of information regarding the duration of its effects on soil chemical attributes and sugarcane productivity. Therefore, the objective of this work was to evaluate the residual effect of gypsum doses on soil chemical attributes, root density and productivity in seven sugarcane crops (ratoon). The experiment was conducted in an experimental area located at Embrapa Cerrados, in Planaltina, DF, Brazil. The experimental design consisted of four gypsum doses (0, 0.5, 5 and 10 t ha-1) distributed in randomized blocks with four replications. Gypsum was applied only one time to the soil surface after sugarcane planting in July 2009. After 13 and 87 months of gypsum application under sugarcane cultivation, the soil was collected from layers up to 120 and 200 cm deep, respectively. For evaluation of the soil chemical attributes: sulfate (S-SO 4 2-), calcium (Ca 2+), magnesium (Mg 2+) and aluminum saturation (m) were assessed. Also, the root dry mass density was evaluated after the first and seventh sugarcane crops, in September 2010 and 2016, respectively. Furthermore, the variables leaf macronutrient concentrations (N, P, K, S, Ca and Mg), stalk yield and total reducing sugars (TRS) were analyzed in all seven crops/ratoons (first is the main crop and other six are ratoons). The application of 5 t ha-1 gypsum increased SO 4 2and Ca 2+ and reduced the aluminum saturation after 13 and 87 months, with higher intensities in the subsurface layers of the soil. As a consequence of this chemical conditioning of the subsurface soil layers, the root dry mass density was increased by 18 and 37% in the 0-120 and 0-200 layers, respectively, after the first (main) and seventh sugarcane crops (ratoons) in relation to the absence of gypsum application. Furthermore, treatments with 5 and 10 t ha-1 of gypsum increased the leaf contents of S, Ca and N in relation to treatments with 0 and 0.5 t ha-1 of gypsum. As a consequence of the increased root growth and better nutrition of sugarcane, the use of gypsum provided a long residual effect, observed in the increase of stalk and sugar yields.

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