942 resultados para Manejo de residuos
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The intensive use of the land for agricultural propose causes a series of modifications in attributes, which can take to soil degradation. In this context, the main goal of this research was to evaluate the influence of the soil tillage systems and management on its physical and hydric characteristics. The evaluations were carried out in July of 1999, at experimental plots of a Latossolo vermelho, a clay oxisoil, in the Faculdade de Engenharia Agrícola of the UNICAMP, at the county of Campinas, state of São Paulo. These plots were managed with the following treatments, along a period of eight years: no-tillage, chisel ploughing, conventional system with disk ploughing and revolving hoe. The evaluated physical and hydric parameters of the soil were: soil bulk density, particle density, total porosity, macro-porosity, micro-porosity, soil-water retention curve, hydraulic conductivity and basic infiltration. Significant differences were observed between the treatments on soil bulk density, infiltration, total porosity, macro-porosity and the micro-porosity. The chisel ploughing and no-tillage systems presented the higher values of soil bulk density; nevertheless in these conservationist systems were observed the higher values of basic infiltration.
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Agronomic practices that help farmers to raise yield and reduce costs must be studied to ensure agricultural sustainability. Thus, the objective of this study was to analyze economically the effect of soil management and nitrogen fertilization in maize crops. Treatments consisted of a combination of 3 soil management techniques (plow harrows + floating harrows, chisel + floating harrows, and no-tillage), 5 periods of nitrogen fertilization (control - 0 kg ha -1 N; 120 kg ha -1 after sowing (S); 120 kg ha -1 in the V 6 stage; 30 kg ha -1 (S) + 90 kg ha -1 in V 6; 30 kg ha -1 (S) + 45 kg ha -1 in V 4 + 45 kg ha -1 in V 8 The total operating cost (TOC), gross revenue (GR), operating profit (OP), profitability index (PI), break-even yield, and break-even price were estimated. It was concluded that the no-tillage system, after 11 years of management, associated with nitrogen fertilization promotes positive PI and OP, being useful to farmers.
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Mapping the plant nutritional condition allows viewing different regions in a cropping area, providing the producers with different criteria to use foliar and soil fertilization. The aim of this study was to evaluate the spatial variability of the nutritional condition of canephora coffee (Coffea canephora Pierre ex Froehner) regarding the site specific management of foliar and soil fertilization. In a one hectare area 60 georeferenced points were sampled at irregular intervals. There were five plants in each sampled point; two pairs of leaves were removed from the lateral branches (3 rd and 4 th pairs from extremity to the basis) in the cardinal points of each plant, counting up 40 leaves per point. The foliar samples were chemically analyzed for the following nutrients: N, P, K, Ca, Mg, S, B, Cu and Zn. The same pattern of spatial dependence was presented with adjustment for K and B. Except for N and P, which presented random distribution, the other nutrients presented mild to severe spatial dependence justifying the geostatistical data analysis for making maps for differential and located, foliar and soil fertilizer application in coffee crop.
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The implants are usually used after removal of the eye or its internal content, in order to maintain the orbital volume or, as in medicine, provide also the subsequent placement of ocular prosthesis. Considering prosthetic surgery procedures of high relevance in human and veterinary ophthalmology, this paper seek to review the main types of implants described in national and international literature, as well as describe the main complications when they are used in humans and veterinary patients.
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The irrigation scheduling is basically the adoption of pre-established criteria to define the time and the amount of water to be applied through irrigation systems. Hence, the objective of this work was to develop and test a spreadsheet of easy comprehension, handling and interpretation by growers, which uses as inputs the physical-hydric soil attributes and tensiometer readings to the determination of irrigation depth and time. The spreadsheet enables the grower to make reading and to know in a fast way how much water to apply into the soil. The test of the spreadsheet was performed in an irrigated orchard of grapevines in Petrolina, State of Pernambuco, Brazil. Soil water retention curves and tensiometer readings from the effective rooting depth were used as a basis for obtaining the soil water matric potential, soil water content, water availability, soil water content to be replaced, net and gross irrigation depth and irrigation time. The analysis of the use of the irrigation scheduling spreadsheet resulted in a shorter time for irrigation in relation to the irrigation scheduling based only on the crop evapotranspiration. The spreadsheet can be helpful to growers adjust irrigation depth when irrigation scheduling is based only on crop evapotranspiration.