40 resultados para agroecossistemas


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Leaf area estimate may contribute to understand the relationships of interference among weeds and crops. The objective of this research was to obtain a mathematical equation to estimate the leaf area of Euphorbia heterophylla based on linear measures of the leaf blade. Correlation studies were carried out using the real leaf area and leaf length (C) and the maximum leaf width (L) of 200 leaf blades which were collected from several agroecosystems at Universidade Estadual Paulista in Jaboticabal, SP, Brazil. The evaluated statistic models were: linear Y = a + bx; simple linear Y = bx; geometric Y = ax b; and exponential Y = ab x. All of the evaluated models can be used for E. heterophylla leaf area estimation. The simple linear regression model is suggested using C*L and taking the linear coefficient equal to zero. Thus, an estimate of the leaf area of E. heterophylla can be obtained using the equation Af' = 0.6816*(C*L).

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Planning is an essential instrument for the agricultural occupation of the lands, because it supports the activities of food production and raw materials. It must be driven by techniques that provide the sustainability of these activities, so that also ensures the environmental balance of agroecosystems. Lands misuse can be considered as one of the causes of frustration of agricultural activities. Thus, the occurrence of discrepancies between the effective use (real use) of the land and its agricultural aptitude can compete, in many cases, to the decrease of productivity, as well as for soil degradation. In this way, this research intends to study the relationship between the temporary cultivations, halfperennial cultures, perennial and its developmental environment, determining the edaphoclimatic characteristics of landscapes. From then on, a letter shall be subject to the use and occupation of the soil for agriculture in the municipality of Cristais Paulista-SP, aiming to describe the spatial organization of land use and vegetation cover, and emphasizing management and conservative practices. For that, climatic factors were characterized, fundamentally humidity, temperature and luminosity; edaphics, including parental material, chemical and physical properties, fertility, soil temperature and climatic zoning; biotic, referring to the suitability of different cultures or to be implanted; physical, such as geomorphology, slope, geology, hypsometry and hydrology; socioeconomic, in particular production and marketing seasons; and the way they all, together, affect the adaptation, distribution and production of crops. Using this information, the zoning of the area of study was done based on the 21 nominated groups obtained, in addition to recommendations and suggestions for handling each type of cultivation... (Complete abstract click electronic access below)

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O século passado foi marcado por grandes avanços tecnológicos na agricultura que culminaram com a chamada “Revolução Verde”, a qual é hoje, comprovadamente, considerada como um modelo insustentável. Tal fato tem motivado instituições científicas e agricultores a buscarem por novos paradigmas para a produção. A agroecologia tem se destacado por abordar o manejo de agroecossistemas dentro de uma visão holística, sistêmica e participativa, subsidiando a recuperação das suas funções e a autonomia durante a transição agroecológica. Nesse contexto, a utilização de ferramentas para avaliação e monitoramento do processo, como a análise de indicadores de sustentabilidade, é fundamental. O presente estudo teve como objetivo monitorar participativamente o grau de sustentabilidade de duas unidades de produção orgânica em Jaguariúna-SP, após cinco anos de uma primeira avaliação. Foram analisados 81 indicadores, abordando quatro dimensões da sustentabilidade: ambiental, social, econômica e política. Os resultados foram obtidos de forma consensual e participativa entre pesquisadores e agricultores, enriquecendo o estudo. Do ponto de vista global, houve um leve avanço no grau de sustentabilidade das duas propriedades. No entanto, ambas continuam no mesmo nível de transição agroecológica apresentado em pesquisa realizada em 2005.

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Studies with organic systems have shown the feasibility and ecological and social sustainability of these agroecosystems, unlike the systems agrochemicals (conventional) production. Some studies have concluded that for the model agrochemical exists less interaction between the flow of internal energy, basically the crop receives all inputs to production with no increase in "energy quality" within the system, while in the organic model of production has increased interaction between different resources in the system. The current economic and ecological crisis, exposed no sustainability of the production pattern of industrialized agriculture developed in a way, showing the dependence of developed countries on imports of agricultural commodities produced in the third world, among there coffee. Given these facts, developed a survey to identify problems in the Alta Paulista region, west of São Paulo State, in relation to coffee production systems. Actually, the fundamental problem, according to the research, farmers in this region, is to choose a viable production system correctly (environmental, social and economic); agrochemical or organic. The objectives of this study were to analyze the yield of production systems and agro-chemical and organic coffee in the period from 2003 to 2007, in 30 producing properties, located in this region, in order to point the production system to produce the highest yield. According to the methodology of CONAB, data collected were recorded on spreadsheets to be used as variables in statistical analysis models and mathematics. We performed a descriptive analysis of productivity data and were used for statistical analysis tests for parametric and nonparametric analysis of variance. The mathematical analyses of the curves were prepared with Origin for Windows 6.0 software, which uses numerical methods to fit the data supplied to a function of variable parameters. Unlike conventional systems of production, the organic system showed greater viability of the production model. Furthermore, with the quantitative modeling proposal, it is possible to perform the evaluation of these types of investments, providing more security to the farmer at the time of decision.

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A produção de alimentos e matérias-primas é considerada um dos maiores desafios da atualidade. Assim, os impactos gerados pela atividade da agricultura são muitos, como por exemplo, erosão dos solos, poluição de águas doces e geração de resíduos. Com isso faz-se necessário o desenvolvimento de tecnologias para promover a redução desses impactos. O presente trabalho tem como objetivo apresentar e discutir análises energéticas em sistemas de produção agrícola como uma ferramenta capaz de destacar a dependência dos agroecossistemas de energia externa e de fontes não renováveis, particularmente de fontes fósseis. Assim, com o uso dessa ferramenta, alternativas para uma produção agrícola com menos impacto ambiental pode ser alcançada, proporcionando a ampliação das possibilidades para uma produção mais sustentável.