340 resultados para cobertura de solo
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia - FEIS
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Pós-graduação em Agronomia - FEIS
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O presente trabalho teve como objetivo, mapear o uso da terra das sub-bacias dos córregos São José e Água do Ventura no ano 2000, e verificar, como esta ocupação vem atuando nos processos de assoreamento dos corpos de água. O estudo teve como base, um mosaico em escala nominal aproximada de 1:10.000, produzido a partir de fotografias aéreas verticais do ano 2000, em escala nominal aproximada 1:30.000. Os resultados permitiram constatar que a pastagem foi a maior ocupação do solo, com 430,89 ha, correspondente a 65,21% da área estudada. Devido ao manejo inadequado do solo, é a cobertura vegetal que mais produz sedimentos por ocasião das chuvas, merecendo cuidados especiais para evitar os processos erosivos do solo. Foi constatado também, que os serviços de adequação e melhoria de estradas rurais, executados nas estradas municipais BRU-030 (antiga Bauru/Piratininga) e variante da BRU-030, atingiram seus objetivos, pois, praticamente, acabaram com a erosão das estradas, permitindo tráfego o ano inteiro, reduzindo o custo de manutenção das estradas e aumentando o abastecimento do lençol freático, além de outros benefícios.
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Pós-graduação em Geografia - FCT
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The effects on soil chemical properties brought about by cover crops vary considerably. This study was conducted to evaluate nutrient uptake by five cover crops used for grain, seed and forage production at different seed densities per hectare, as well as uptake by spontaneous vegetation, and their effect on the chemical properties of two Oxisols when grown in rotation with soybean and corn. The experiments were set up in Votuporanga, SP, Brazil and Selvíria, MS, Brazil in March 2008 after conventional soil tillage. A randomized complete block experimental design was used with four replications with the following cover crops at different seed densities: Sorghum bicolor at 6, 7 and 8 kg ha-1; Pennisetum americanum at 10, 15 and 20 kg ha-1; Sorghum sudanense at 12, 15 and 18 kg ha-1; hybrid of Sorghum bicolor with Sorghum sudanense at 8, 9 and 10 kg ha-1; and Urochloa ruziziensis at 8, 12 and 16 kg ha-1. We also used a spontaneous vegetation control. After management of the cover crops, in the first year of study, soybean was sown in no-tillage system and, in the second year, corn was sown, also in a no-tillage system. We evaluated the dry matter yield of different cover crops, nutrient uptake by the cover crops, and the chemical changes in the soil. It was found that in clayey soils with high aluminum content, as in Selvíria, sudan grass at a seed density of 18 kg ha-1, and sorghum at a seed density of 6 kg ha-1, in combination with liming, contributed to reduction of aluminum content and high potential acidity and an increase in base saturation. The different seed densities of each cover crop did not affect the dry matter yield of the cover crop itself, but affected nitrogen uptake of the hybrid Sorghum bicolor with Sorghum sudanense at a seed density of 10 kg ha-1, with lower uptake than at a seed density of 8 kg ha-1. Seed density also affected the organic matter content in the soil with sudan grass, with the seed density of 15 kg ha-1 providing more organic matter content than a seed density of 18 kg ha-1.
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Research has been conducted to identify the best nitrogen (N) rate for maize in most diverse types of soil management. However, there is no agreement on the results, once the dynamic of N is influenced by soil management and cover crops. This study evaluated dry mass production and nutrient uptake by cover crops, agronomic parameters and grain yield of maize in response to soil management and N rates. Field trials were carried out in Selvíria, Mato Grosso do Sul State, Brazil, in the growing seasons of 2009/2010 and 2010/2011, on a clayey Rhodic Haplustox (20º 20' S and 51º 24' W, 340 m asl). Thirty-six treatments were established with four replications, in a randomized blocks design, with the combination of cover crops (millet, Crotalaria juncea and millet + Crotalaria juncea), soil management systems (tillage with chisel plow + lightweight disking, heavy disking + lightweight disking, and no-tillage) and topdressing N rates (0, 60, 90 e 120 kg ha-1 - urea as source). Maize hybrid DKB 350 YG® was used and N applied at stage V5 (fifth expanded leaf). A linear increase with the increase of N rates was observed for chlorophyll leaf index, leaf N content, ear length and diameter, and grain weight and yield. Previously grown sunn hemp and millet + sunn hemp grown, associated with 120 kg ha-1 N for maize, induced a higher grain yield after two growing seasons.
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Research has investigated the best nitrogen rate for maize under the most diverse types of soil management. The aim of this study was to evaluate the influence of cover crops, soil management and topdressed N rates on the dry matter production, nutritional status, plant lodging, plant height and first-ear insertion of maize. Field experiments were carried out in Selvíria, Mato Grosso do Sul State, Brazil, in the growing seasons of 2009/2010 and 2010/2011, on a clayey Rhodic Haplustox (20º 20' S and 51º 24' W, at 340 m asl). Thirty-six treatments were established with four replications, in a randomized blocks design, to test combinations of cover crops (millet, Crotalaria juncea and millet + Crotalaria juncea), soil management (tillage with chisel plow + lightweight disking, heavy disking + lightweight disking, and no-tillage system) and N rates (0, 60, 90 e 120 kg ha-1 - urea as source). The maize hybrid DKB 350 YG® was used and topdressing N applied at stage V5 (fifth expanded leaf). Previously grown sunn hemp and millet + sunn hemp resulted in a higher shoot dry matter, P leaf content and total N, P and K uptake. In the no-tillage system, the initial and final population and shoot dry were highest, and first-ear insertion and plant height lower. The application of 120 kg ha-1 topdressed N increased the P leaf content, N and P in the entire plant, shoot dry matter, total N, P and K uptake, plant height, and the first-ear insertion of maize.
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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Pós-graduação em Agronomia - FEIS
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The adoption of management practices that reduce water losses is essential to conserve moisture and improve soil temperature, especially in arid and semiarid environments of the Brazilian Northeast, characterized by high evapotranspiration and the adoption of irrigation with saline water, which harms growth and yield of commercial crops. Given these factories, an experiment was conducted in Nova Floresta, Paraiba, from August 2010 to February 2011 in Oxisoil, in order to evaluate the production of bell pepper and soil moisture in grooves with side trim, and application of biofertilizer and mulch cattle. The experimental design was randomized blocks with four replications using a factorial 2 x 2 x 2 for the ground beef with and without biofertilizer, with and without residues of sisal fiber (Agave sisalana), with and without the side facing the grooves, to reduce lateral water losses by infiltration of water with polyethylene plastic film. From the results, the lining of the lateral grooves provided higher values of soil moisture, number of fruits, fruit mass, plant production and productivity, bell pepper plants. It was also found that the combination of biofertilizer and mulch the ground beef remained wetter in the first 15 cm depth.
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Evaluated the evapotranspiration (ETc) and the efficiency of water use (USA) by the fig tree 'Purple Valinhos' submitted to irrigation and mulching (bagacilho of sugar cane crushed) in the first production cycle, at conditions of Botucatu, St. Paul. We used the method of soil water balance and to obtain the reference evapotranspiration method was used Montheit FAO Penman 56. For the assessment of crop coefficients (kc) we adopted the following phenological distribution: phase 1 - between transplanting and 20% of the vegetative (DV), ii) phase 2 - 20 to 80% DV, and iii) phase 3 - fruiting. Observe the cumulative ETc 409.4 and 465.8 mm in 254 days after transplanting (DAT) and averages of 1.47 and 1.67 mm day(-1), with and without mulching (CC and SC). The crop coefficients (kc) mediums were 0.16, 0.43 and 0.49 for SC and 0.18, 0.44 and 0.50 for CC, in phases 1 and 3, respectively. The EUA values decrease with increasing the volume of water received and ranged between 1.65 and 3.32 kg of green figs per m(3) of water for irrigated SC and CC.
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)