877 resultados para Agricultural production


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In Brazil the intensive agriculture use, mainly pasture, is the main cause of the presence of extensive areas of degraded lands. This study aimed to assess the impact of different soil management practices in a pasture degraded area used as garbage disposal. The experiment was performed at the Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas - UNICAMP, in Campinas, state of São Paulo, Brazil, from 1990 to 1996. This area has undergone a process of recovery through removal of trash deposited on the surface, in 1985, levelling of soil, followed by application of limestone, subsoiling, planting of legumes (Crotalaria juncea) and crop rotation (soybean and maize). Since 1990 only popcorn maize was grown and established plots managed with different soil tillage systems, including harrow, chisel plow, moldboard plow, no tillage, disk plow and revolving hoe. One plot was planted exclusively with guinea grass (Panicum maximum) to serve as a reference for minimum loss of soil and another grown on a downhill direction to correspond to the expected maximum erosion. There were differences in sediment loss, nutrient loss and productivity of the popcorn maize in the period analyzed. The chisel plow and no tillage treatments caused the slightest loss of soil and nutrients, compared to other tillage systems. The results show that the soil management systems influenced the physical and chemical characteristics of soil, allowing an economical and environmental recovery of the area, providing the conditions for grain agricultural production.

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Environmental factors are important in agriculture and need to be considered for getting good degree of development and reasonable efficiency, by reducing their operating costs. To this end, land use shall be appropriated to the conditions offered by the physical elements of the landscape. By facing such questions, this paper aims is to present of mapping the ability of land use of the hydrographic basins Cavalheiro Stream basin (in the city of Analândia - São Paulo State - Brazil) which presents serious erosion problems. Besides it aims to assess if the current land use in this area is consistent with the identified land use ability. For this we have made a cartographic document that spatializes the various classes of usability and its main restrictions. The correlative analysis between that document and land use data showed that Cavalheiro Stream's current use is predominantly inappropriate with the usability of land, which was identified from the physical attributes of the studied area, except for a few sites that are used for forestry and pasture placed in Western, Eastern and Central-South.

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Against the background of a growing world population, rice (Oryza sativa L.) consumption is expected to grow faster than its production. Therefore, an appropriate question would be: how to increase productivity in the shortterm? In this respect, it becomes important the implementation of modern agricultural production systems, such as upland rice with supplemental sprinkler irrigation. Additional information is needed to maximize the available resources, with special attention given to research on the use of nitrogen. This study aimed to evaluate the agronomic performance of commercial rice cultivars with different plant characteristics in upland conditions with supplemental sprinkler irrigation, when subjected to nitrogen in topdress application at the R1 stage (panicle differentiation). The experiment was arranged in a randomized block with split plot design, with 65 treatments, consisting of the combination of 13 cultivars in the plots, and five nitrogen levels in the subplots (0, 40, 80, 120 and 160 kg ha-1), with four replications. Genetic variability was detected among rice cultivars and the agronomic performance in response to the applied nitrogen. The topdressing application of nitrogen increases, in general, the production components and grain yield in rice. Cultivars BRS Primavera, Caiapó and IAC 202 stood out for grain yield, followed by Baldo, Carnaroli, BRS Curinga and IAC 500 with lower yields.

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In the present study, we examined how residues of nitrogen (N), phosphorus (P) and calcium (Ca) fertilisers affect leaf anatomical traits in Maprounea brasiliensis (Euphorbiaceae), a typical and dominant cerrado (Brazilian savannah) species adapted to dystrophic soils. We predicted that fertiliser residues would alter qualitative and quantitative aspects of M. brasiliensis leaves and would decrease their scleromorphy. Leaves were sampled from plants that were growing in soils previously fertilised with N, P and Ca and in plants that were growing in soils without fertiliser residues. We measured the thickness of the cuticle, the epidermis of adaxial and abaxial surfaces, thickness of palisade parenchyma and spongy parenchyma, total thickness of the leaf, total area of the midrib and leaf mass per area (LMA). We found that plants under fertiliser residues produced fewer scleromorphic leaves with low LMA, thinner cuticle and epidermis and thicker palisade and spongy parenchyma. They also showed a decrease in the size and area occupied by the leaf midvein. However, plants under fertiliser residues produced similar leaf thickness as did the plants in the control group. Our results showed that residual effects of fertilisation changed structural patterns of a typical species of cerrado. Thus, further studies about fertilisation effects on leaf traits are needed because larger areas of the central cerrado are being occupied for agricultural production. © 2013 CSIRO.

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Brazil is a major sugarcane producer and São Paulo State cultivates 5.5 million hectares, close to 50% of Brazil's sugarcane area. The rapid increase in production has brought into question the sustainability of biofuels, especially considering the greenhouse gas (GHG) emissions associated to the agricultural sector. Despite the significant progress towards the green harvest practices, 1.67 million hectares were still burned in São Paulo State during the 2011 harvest season. Here an emissions inventory for the life cycle of sugarcane agricultural production is estimated using IPCC methodologies, according to the agriculture survey data and remote sensing database. Our hypothesis is that 1.67 million hectares shall be converted from burned to green harvest scenarios up to years 2021 (rate 1), 2014 (rate 2) or 2029 (rate 3). Those conversions would represent a significant GHG mitigation, ranging from 50.5 to 70.9 megatons of carbon dioxide equivalent (Mt CO2eq) up to 2050, depending on the conversion rate and the green harvest systems adopted: conventional (scenario S1) or conservationist management (scenario S2). We show that a green harvest scenario where crop rotation and reduced soil tillage are practiced has a higher mitigation potential (70.9 Mt CO2eq), which is already practiced in some of the sugarcane areas. Here we support the decision to not just stop burning prior to harvest, but also to consider other better practices in sugarcane areas to have a more sustainable sugarcane based ethanol production in the most dense cultivated sugarcane region in Brazil. © 2013 Elsevier Ltd. All rights reserved.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Animal - FMVA

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