287 resultados para fator uso e manejo

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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The soil physical quality is defined as the soil capacity to maintain the sustainable productivity during the years. To assess soil physical quality, attributes were evaluated in the layers of 0.0-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40 m in acrustox. The experimental design was entirely randomized, with four systems of use ( corn, sugar-cane, pasture and native vegetation), four soil depths and four replications. The parameter evaluated were: texture, degree of clay flocculation, soil bulk density, porosity, water retention and "S" parameter. The usage and management systems caused soil physical degradation, being greater in pasture system with intensive usage, with smaller soil physical quality for plants development. The soil physical quality, evaluated by physical attributes, followed the following order: native vegetation > maize > sugar-cane > pasture. The Oxisol, although shows present excellent physical structure and needs an adequate management to prevent excessive compaction.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Man cultivates the soil for centuries, but the intensive business and use of the soils under Cerrado vegetation for agricultural production grew out of the seventies. The objective of this study was to evaluate soil physical characteristics as a function of sampling time and the soil uses in a Cerrado area in Uberlandia City - MG, Brazil. The managements were adopted: degraded pasture (M-1), conventional tillage (M-2), minimum tillage (M-3), tillage absence (M-4), no-tillage (NT) for three years (M-5); NT for nine years (M-6), NT for three years after Pinus (M-7), PD for one year after Pinus (M-8) and Pinus forest (M-9) with 25 years old. The evaluations were conducted in 2002/03 growing season, in two areas. The soils were: area 1, an Oxisol (Red Latosol - LV-1, M-1 through M-5) and area 2, two Oxisols (Red Latosol and Red-Yellow Latosol - LVA and LV-2, M-6 through M-9). The physical attributes studied changed depending of the soil class, sampling time and management systems, with emphasis on the area 2 soils, which, in general, better preserved its main physical attributes. Managements with intense tillage, such as the M-2, are the most soil physically degrade, presenting mostly negative changes to soil bulk density, total porosity, microporosity and macroporosity. Since the systems which promote less tillage, in short term, to preserve desirable physical attributes. The M-9 system had the lowest attributes range, compared to the others.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots.

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The conventional system for soil management and preparation has the intensive mechanization as its basic principle and that changes soil properties, especially physical ones, faster and significantly. This study aimed to obtain and compare physical properties such as distribution of particle sizes, density, distribution of pore sizes, curves of water retention and degradation index of a Red Latosol, under intensive cultivation and no-cultivation for six years. Soil samples were collected at depths of 0.1, 0.2, 0.3, 0.4, 0.6, 0.8 and 1.0 m. There was a clay increment as a result of cultivated soil increase. The no-till soil density decreased as depth increased; however, in the arable layer (0.3 m) of the cultivated soil, the opposite was verified. The largest volume of pores was verified in the cultivated soil, especially in the superficial layers. In the smallest applied tension (0.001 MPa), the cultivated soil retained more water; however, starting from 0.033 MPa, the highest humidity values occurred in the no-till soil. The highest degradation index was observed at a depth of 0.1 m in no-till soil. However, that value was superior (0.020) to what is physically considered very poor soil.

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The purpose of the work is to evaluate the stability by dry and humid of theaggregate in different systems or the use and management in Argissolos: agricultural, pasture and torest utilization. This work was realized in agricultural property, in Anhumas city, SR Several analyses including percentage of the aggregate (by way of dry and humid); the weighted mean diameter of the aggregate calculation and statistic analysis. Conclusion: the organic matter content of the A horizon of the soil under forest is 64 % more than the soil under pasture and 79 % more than the soil under annual crop; the WMDA of the aggregate obtained by dry and humid ways of the horizon A and its mean value for the soil decrease in the following sequence: PVAd - forest > PVe -pasture > PVd - annual culture, respectively, with the following values: 1.33560 and 1.445496 (D), 2.81114 and 2.351380 (H); 0.66748 and 1.011830 (D); 2.79642 and 1.624250 (H); 0.32468 and 0.993775 (S), 1.25808 and 0.983135 mm (H); the two methods are equally sensitive to reveal the effect of the soil use and management; the organic matter provides additional stability to the aggregates submitted to humid sieving and clay to the dry sieving: the WMDA obtained by dry and humid ways are statistically different for the soil profiles.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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O solo, um dos principais suportes da produção agrícola tem seu comportamento regido por um complexo conjunto de fatores físicos, químicos e biológicos, razão pela qual o presente trabalho teve como objetivo avaliar as modificações dos atributos físicos de um Nitossolo Vermelho distroférrico com diferentes manejos, na Faculdade de Ciências Agronômicas - UNESP, Campus de Botucatu, São Paulo, Brasil. O delineamento estatístico foi inteiramente casualizado, com seis repetições em três diferentes áreas, sendo uma área de mata nativa, uma área com sistema de preparo convencional do solo e uma área com plantio direto. Foram determinados: matéria orgânica, argila natural, porosidade total, macroporosidade, densidade do solo, resistência à penetração e diâmetro médio ponderado dos agregados. O sistema de preparo convencional apresentou os menores teores de matéria orgânica na camada até 0,20 m. Na resistência à penetração não houve diferença entre os tratamentos. Para as cinco profundidades do sistema de preparo convencional observaram-se maior densidade e teor de argila natural em comparação aos outros sistemas. O sistema de preparo convencional diferiu dos demais tratamentos quanto ao diâmetro médio ponderado, porosidade total e macroporosidade apresentando os menores valores desses atributos.

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV