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The study had the objective to evaluate the effect of the fertilization with filter cake enriched with soluble phosphate on the sugar yield. The experiment carried at Presidente Prudente-SP, used a randomized complete block design, in the factorial scheme 5 x 4, where the first factor consisted of doses of filter cake (0; 0.5; 1.0; 2.0 and 4.0 t ha -1 ) and the second, doses of phosphorus fertilizer (0, 50, 100, 200 kg ha -1 of P 2 O 5 ), with 4 replicates, totaling 80 plots. The results indicated that phosphorus applied in planting furrows improves the quality of sugarcane raw matter by increasing the levels of soluble solids, total reducing sugars and sucrose in the stalks. The phosphorus also increases the productivity of sugar. The filter cake applied in planting furrow has the potential to partially replace the chemical fertilization with phosphate aiming to improve the quality and the productivity of sugar. The best combination was filter cake at dose between 2.6 and 2.7 t ha -1 combined with dose between 160 and 190 kg P 2 O 5 ha -1 for obtaining best response of soluble solids and productivity of sugar.

The chemical degradation of soils, due to acidity, and erosion processes, resulting from a traditional tillage system method, are one of the main factors responsible for decreasing the productive capacity of tropical pastures. Thus, establishing the crop-livestock integration system (CLIS) by applying lime on surface without disrupting the soil is interest. The objectives of this study were to evaluate the chemical changes in a soil following surface application or incorporation of lime and to determine the effects of liming on plant nutrition, corn (Zea mays L.) grain yields, and various yield components in cultivated areas of degraded Brachiaria decumbens Stapf pasture. A randomized block experimental design with a splitplot arrangement consisting of two management systems (tillage and no-tillage system) and three lime rates (0.0; 2.7 and 5.4 Mg ha À1) was used. The highest reactivity of calcium carbonate was observed after six months of liming, since during the sampling time the level of exchangeable Ca 2+ and Mg 2+ decreased to 0.05 m depth, and increased Al 3+ and soil acidity to 0.3 m. The incorporation of lime did not increase the movement or reaction of the bases in the degraded soil profile. Therefore, surface liming under perennial forage crop residues (B. decumbens Stapf. pasture) provided the best alternative to increase the soil pH index at a depth of up to 0.3 m. Macronutrients uptake by plant, yield components, and corn grain yield were not affected by the application method. However, the use of limestone showed viability to maximize up to 20% in corn productivity, regardless of lime rate. The results suggest that it is possible to ameliorate soil acidity and chemical properties of degraded grassland only by surface application of limestone; however, the strategy is considered effective just for soils with no physical restriction to root development. 2015 Elsevier B.V. All rights reserved.

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Resumo -O objetivo deste trabalho foi quantificar a produtividade de fitomassa, o teor e acúmulo de nitrogênio (N), e a relação carbono/nitrogênio (C/N) de monocultivos de sorgo (Sorghum bicolor) e milho (Zea mays) e de seus consórcios com guandu-anão (Cajanus cajan), crotalária (Crotalaria juncea), tremoço branco (Lupinus albus), girassol (Helianthus annuus) e nabo-forrageiro (Raphanus sativus), manejados em diferentes estádios. O experimento foi conduzido de março a julho de 2008, em Argissolo Vermelho distroférrico de textura média, no sistema plantio direto. O delineamento experimental foi o de blocos completos ao acaso, com quatro repetições, e parcelas subdivididas, constituído pelos tratamentos: monocultivos de sorgo e milho e seus respectivos consórcios com guandu-anão, crotalária, girassol, nabo-forrageiro e tremoço branco, nas parcelas; e épocas de corte, aos 60, 90 e 120 dias após a semeadura nas subparcelas. Consórcios de sorgo e milho com outras espécies superaram expressivamente a produtividade de fitomassa de seus monocultivos que ainda acumularam menos N e apresentaram maiores relações C/N na fitomassa. Para aumentar a produtividade de fitomassa, a melhor época de corte é aos 120 dias após a semeadura das culturas de cobertura. O corte aos 90 dias após a semeadura propicia o maior acúmulo de N e as menores relações C/N.Termos para indexação: acúmulo de nitrogênio, cobertura do solo, espécies de cobertura, sistema plantio direito. Biomass and C/N ratio in intercrops of sorghum and maize with cover cropsAbstract -The objective of this work was to quantify the biomass production, the content and accumulation of nitrogen (N) and the carbon/nitrogen (C/N) relation in monocultures of sorghum (Sorghum bicolor) and corn (Zea mays), and intercrops with pigeon pea (Cajanus cajan), sun hemp (Crotalaria juncea), white lupine (Lupinus albus), sunflower (Helianthus annuus) and turnip forage (Raphanus sativus), managed in different stages. The experiment was carried out from March to July 2008, in a Haplic Acrisol, medium texture, under no-tillage. A randomized complete block design, with four replicates and split plots with the following treatments: monocultures of sorghum and maize and their intercrops with pigeon pea, sunn hemp, sunflower, turnip forage, white lupine, in the plots; and cut management times, at 60, 90 and 120 days after sowing, in the subplots. Intercrops of sorghum and maize with other species significantly outweighed the biomass productivity of their monocultures, which accumulated less N and had higher C/N ratio of biomass. The best cut management time is at 120 days after sowing of the cover crops, for dry biomass yield. Cutting at 90 days after sowing promoted the greater N accumulation and the lower C/N ratios.