Uso de lodo de esgoto na produção de tapetes de grama esmeralda

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

Características físicas do solo e produção de tapetes de grama esmeralda em função de manejos mecanizados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aplicação e efeito residual do lodo de esgoto em sistemas de produção de tapetes de grama esmeralda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mobilização do solo, velocidade de infiltração de água e taxa de cobertura do solo na grama esmeralda, sob manejos mecanizados

The excessive compaction of the soil observed in sod production systems, affects the physical attributes of the soil, which can influence the water infiltration into the soil and hence the rate of soil cover by turfgrasses and time of the sod production. To minimize the effects of soil compacting, some producers use soil preparation equipment that raises the soil on the surface but does not cause excessive roughness which may harm the quality of the sod. Thus, the aim of the present study was to evaluate the infiltration rate and soil cover rate due to different management mechanized in the zoysiagrass sod production. The experimental design had random plots and four replications. The treatments consisted of five mechanized managements of soil: witness (without the use of equipment); coulter blade disc harrow used once (1CB), coulter blade disc harrow used twice (2CB), surface chisel used once (1C), surface chisel and coulter blade disc harrow used once (1C + 1CB). The treatments with 2CB and 1C + 1CB provided greater basic water infiltration speed in the soil and higher rate of soil cover by the turfgrass. The rate of soil cover by turfgrass is positively correlated with water infiltration rate at 133 and 226 DAP, demonstrating the influence of managements used in zoysiagrass sod production and the increment in the infiltration rate of water. Soil preparation utilizing coulter blade disc harrow used twice or surface chisel and coulter blade disc harrow used once is recommended under the conditions this study was done.

Placement Methods of Phosphorus and Potassium for Corn and Soybean Managed with No-till and Chisel-plow/Disk Tillage

No-till management limits the incorporation of crop residue and fertilizer with soil resulting in wetter, colder soils and the accumulation of organic matter, phosphorus (P), and potassium (K) near the soil surface. Banding of P and K could be more effective than broadcast fertilization by counteracting stratification, applying nutrients in the root zone (starter effect), and minimizing reactions with the soil that may reduce their availability to plants. Therefore, this long-term study was established in 1994 to evaluate P and K fertilizer placement methods and grain yield of corn-soybean rotations managed with notill and chisel-plow/disk tillage.

Shadow Analysis of Soil Surface Roughness Compared to the Chain Set Method and Direct Measurement of Micro-relief.

Erosion potential and the effects of tillage can be evaluated from quantitative descriptions of soil surface roughness. The present study therefore aimed to fill the need for a reliable, low-cost and convenient method to measure that parameter. Based on the interpretation of micro-topographic shadows, this new procedure is primarily designed for use in the field after tillage. The principle underlying shadow analysis is the direct relationship between soil surface roughness and the shadows cast by soil structures under fixed sunlight conditions. The results obtained with this method were compared to the statistical indexes used to interpret field readings recorded by a pin meter. The tests were conducted on 4-m2 sandy loam and sandy clay loam plots divided into 1-m2 subplots tilled with three different tools: chisel, tiller and roller. The highly significant correlation between the statistical indexes and shadow analysis results obtained in the laboratory as well as in the field for all the soil?tool combinations proved that both variability (CV) and dispersion (SD) are accommodated by the new method. This procedure simplifies the interpretation of soil surface roughness and shortens the time involved in field operations by a factor ranging from 12 to 20.

Effect of surface conditions on flow of a micropolar fluid driven by a porous stretching sheet

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Some surface profiles of a strip after plane-strain indentation by rigid bodies with serrated surfaces

This paper is concerned with the surface profiles of a strip after rigid bodies with serrated (saw-teeth) surfaces indent the strip and are subsequently removed. Plane-strain conditions are assumed. This has application in roughness transfer of final metal forming process. The effects of the semi-angle of the teeth, the depth of indentation and the friction on the contact surface on the profile are considered.