104 resultados para Polyculture


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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Analisou–se o crescimento dos peixes, a composição das espécies e a produtividade de quatro policultivos (P75, P78, P87 e P207), visando melhorar o manejo e a produtividade pesqueira dos pequenos açudes (0,1–5,0ha) do Semi–Árido brasileiro. Simulou–se as condições desses açudes em viveiros com 120 e 5.000 m2 de área, sem renovação de água, utilizando moderada quantidade de adubo e fertilizante. A biomassa inicial variou de 75 a 207kg há–1, sendo formada por: tilápia do Nilo (Oreochromis niloticus), curimatã pacu (Prochilodus argenteus), carpa comum (Cyprinus carpio), tambaqui (Colossoma macropomum) e tucunaré (Cichla ocellaris). Os peixes apresentaram baixo crescimento (< 0,01g g–1d–1) após 75 dias de criação (P78 e 87). O crescimento do tambaqui, da tilápia e da curimatã foi reduzido após 53 dias (P75). Em moderada biomassa, o crescimento do tambaqui foi inferior ao da carpa e da curimatã (P207). A produtividade da tilápia atingiu 720 kg ha–1ano–1 (P78), sendo reduzida para 220 kg ha–1ano–1 devido ao processo reprodutivo (P75 e P207). A produtividade da carpa de 1.600 kg ha–1ano–1 foi superior a dos outros peixes (P87). A biomassa inicial de 75 kg ha–1 (60:30:4:3:3% de tilápia, tambaqui, carpa, curimatã e tucunaré, respectivamente) otimizou o crescimento e a produtividade dos peixes. A utilização de tilápias monossexadas e o fornecimento da alimentação suplementar ao tambaqui tornam–se imprescindíveis ao policultivo.

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Pós-graduação em Aquicultura - FCAV

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This monograph is part of the works developed in the Scientific Initiation aimed at updating and improving the Atlas of Brazilian Agrarian Question - AQAB. For pioneering and scope of work-matrix, the objective this first part focused on the development of issues related to agricultural production, being drawn maps with data from the Municipal Agricultural Production-PAM 2012; Municipal Livestock Research-PPM 2012; Production of Vegetable Extraction and Forestry-2012, all analyzed from bibliographic review and joint interpretation of tables and graphs. Pari passu, this topic allowed the development of studies on peasant farms, because they are correlated subjects. Peasant farmers produce large portion of the food served to the population. Its features are its mode of production in the field, the way in which the activities take place within the family, the struggle for their social reproduction and by the earth, the practice of polyculture, preservation of the environment and the genetic diversity of species. The surplus production is sold on the market to meet other family demands unmet by production on their properties. We understand that both terms; Peasant or Farmer, refer to the same subject, but with different interpretations of their way of social reproduction and market relations...

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This monograph is part of the works developed in the Scientific Initiation aimed at updating and improving the Atlas of Brazilian Agrarian Question - AQAB. For pioneering and scope of work-matrix, the objective this first part focused on the development of issues related to agricultural production, being drawn maps with data from the Municipal Agricultural Production-PAM 2012; Municipal Livestock Research-PPM 2012; Production of Vegetable Extraction and Forestry-2012, all analyzed from bibliographic review and joint interpretation of tables and graphs. Pari passu, this topic allowed the development of studies on peasant farms, because they are correlated subjects. Peasant farmers produce large portion of the food served to the population. Its features are its mode of production in the field, the way in which the activities take place within the family, the struggle for their social reproduction and by the earth, the practice of polyculture, preservation of the environment and the genetic diversity of species. The surplus production is sold on the market to meet other family demands unmet by production on their properties. We understand that both terms; Peasant or Farmer, refer to the same subject, but with different interpretations of their way of social reproduction and market relations...

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Rising water demands are difficult to meet in many regions of the world. In consequence, under meteorological adverse conditions, big economic losses in agriculture can take place. This paper aims to analyze the variability of water shortage in an irrigation district and the effect on farmer?s income. A probabilistic analysis of water availability for agriculture in the irrigation district is performed, through a supply-system simulation approach, considering stochastically generated series of stream-flows. Net margins associated to crop production are as well estimated depending on final water allocations. Net margins are calculated considering either single-crop farming, either a polyculture system. In a polyculture system, crop distribution and water redistribution are calculated through an optimization approach using the General Algebraic Modeling System (GAMS) for several scenarios of irrigation water availability. Expected net margins are obtained by crop and for the optimal crop and water distribution. The maximum expected margins are obtained for the optimal crop combination, followed by the alfalfa monoculture, maize, rice, wheat and finally barley. Water is distributed as follows, from biggest to smallest allocation: rice, alfalfa, maize, wheat and barley.

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We studied the relationships among plant and arbuscular mycorrhizal (AM) fungal diversity, and their effects on ecosystem function, in a series of replicate tropical forestry plots in the La Selva Biological Station, Costa Rica. Forestry plots were 12 yr old and were either monocultures of three tree species, or polycultures of the tree species with two additional understory species. Relationships among the AM fungal spore community, host species, plant community diversity and ecosystem phosphorus-use efficiency (PUE) and net primary productivity (NPP) were assessed. Analysis of the relative abundance of AM fungal spores found that host tree species had a significant effect on the AM fungal community, as did host plant community diversity (monocultures vs polycultures). The Shannon diversity index of the AM fungal spore community differed significantly among the three host tree species, but was not significantly different between monoculture and polyculture plots. Over all the plots, significant positive relationships were found between AM fungal diversity and ecosystem NPP, and between AM fungal community evenness and PUE. Relative abundance of two of the dominant AM fungal species also showed significant correlations with NPP and PUE. We conclude that the AM fungal community composition in tropical forests is sensitive to host species, and provide evidence supporting the hypothesis that the diversity of AM fungi in tropical forests and ecosystem NPP covaries.

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Results from the humid tropics of Australia demonstrate that diverse plantations can achieve greater productivity than monocultures. We found that increases in both the observed species number and the effective species richness were significantly related to increased levels of productivity as measured by stand basal area or mean individual tree basal area. Four of five plantation species were more productive in mixtures with other species than in monocultures, offering on average, a 55% increase in mean tree basal area. A general linear model suggests that species richness had a significant effect on mean individual tree basal area when environmental variables were included in the model. As monoculture plantations are currently the preferred reforestation method throughout the tropics these results suggest that significant productivity and ecological gains could be made if multi-species plantations are more broadly pursued. (c) 2006 Elsevier B.V. All rights reserved.

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Anuran species diversity and abundance were evaluated in different farming status of cocoa plantation in Ore, Ondo State, Nigeria. Applying the combination of visual encounter survey (VES) and acoustical survey (AES), the different farms surveyed were categorized as; 1) pure cocoa farms with pesticides applied (PCWP); 2) pure cocoa farms without pesticides application; 3) intercropped cocoa farms with pesticides applied (ICWP); and 4) intercropped cocoa farms without pesticides application (ICNP). The surrounding primary/secondary forest (PSFV) was sampled applying the transect method. A mean total of 690±2.6 anurans belonging to 28 species, 14 genera and 9 families were recorded during the study. Out of these, 10, 19, 17, 22 and 26 species were recorded respectively from PCWP, PCNP, ICWP, ICNP and PSFV. The anuran species richness was significantly different between the different cocoa plantation status and the forest sites (F4, 10 = 20.55, P< 0.01). The highest mean number of individuals (190±9.5) was observed at ICNP followed by PSFV (183±5.7), while the least was at PCWP (77±8.0). There was also significant difference (F4, 10 = 150.48, P< 0.01) between the abundance of anuran species at the various sites. Diversity indices (Shannon and Margalef) showed that the forest sites had the greatest (3.204 and 4.799) respectively while the pesticide using pure cocoa farms had the least (1.853 and 2.072). Generally, the result of the study clearly indicated that pesticide use cocoa farms were significantly lower compared to other sites. Farmers are encouraged to engage in intercropping (polyculture) especially with food and economic crops in a biodiversity friendly manner which could have similar characteristics of a natural ecosystem, thereby enhancing the biological diversity of agro-ecosystems.

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Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake (118.48-118.72°E; 33.36-33.38°N) are reported. Area farmed has remained relatively unchanged but production (59 932 t in 2012) increased steadily over the last 7 years, indicative of the viability and sustainability of the farming system that has gradually replaced intensive Chinese major carp polyculture around Hongze Lake. Results showed that production range was 135-2400 kg ha(-1) cycle(-1) (mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed to a normal distribution curve, with 66.7 % of farms yielding 900 kg ha(-1) cycle(-1) or more. Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.