20 resultados para Semi-arid conditions


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In the semi-arid region of northeastern Brazil, the Atriplex plant genus has been efficient in removing salts from soils irrigated with saline wastewater. However, this removal might not be significant compared with the amount of salts added to the soil by the wastewater irrigation. Considering this aspect, the aim of this work was to evaluate the effectiveness of Atriplex nummularia Lindl plants in the remediation of a soil submitted to saline wastewater irrigation. Despite the known inhibition effect of saline wastewater on soil enzyme activity, the cultivation of Atriplex nummularia Lindl maintained the treated soil enzyme activity levels similar to the ones found in natural soils.

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Native fruits from Caatinga vegetation can be an important alternative to improve the productive performance of kids in the semi-arid region of Brazil. This work aimed to evaluate the effect of supplementation with Umbuzeiro fruits in natura over the weight gain and anthelmintic control of kids kept in Buffel grass pasture in the semi-arid zone of Pernambuco, Brazil. Twenty-four castrated, crossbreed kids were allocated into three treatments: 1) Control (n = 8) fed exclusively with Buffel grass; 2) Umbu 1x (n = 8) fed with fruits once a week and 3) Umbu 3x (n = 8) fed with fruits for three times a week. The following parameters were evaluated: variation of body weight, faecal egg counts (FEC) and coproculture. Overall, the average consumption of Umbu fruits in natura was 1.48 kg/animal/day, which corresponded to 133.5 g daily dry matter intake (DMI/animal/day). There were no significant difference (P>0.05) for any parameters evaluated. During the experimental period, the overall daily weight gain was variable between 108.75 to 116.70 g/animal/day and the average FEC was 436 eggs. In the present study, the goat kids supplemented with fresh umbu fruits showed a good productive performance, however the supplementation with umbu did not control the infestation of gastrointestinal nematodes in kids.

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RESUMO: A avaliação participativa permite inferir se os sistemas agrícolas necessitam de melhorias e quais conhecimentos podem promover incrementos. Esse trabalho objetivou avaliar diferentes sistemas de produção na Comunidade Pé de Serra Cedro, Sobral-CE, utilizando metodologia participativa com agricultores locais através de indicadores de qualidade do solo e sanidade dos cultivos. Os sistemas de produção avaliados foram quatro, com as seguintes descrições: sistema tradicional: plantio de culturas anuais, com queima da área a 3 anos; sistema tradicional + esterco; sistema tradicional + esterco + leucena; e sistema roçado agroecológico. A inserção de práticas edáficas como aplicação de estercos e implantação de leguminosas incrementaram sistemas de produção tradicionais no semiárido cearense, mesmo em curto prazo de avaliação. A utilização de roçados agroecológicos diferenciou-se para indicadores do solo e sanidade dos cultivos em relação aos manejos tradicionais, com indicador médio para atributos do solo de 8,6 e para sanidade de cultivos em 8,4. [Participatory evaluation indicators of soil and crop shealth in production systems in comunity Pé de Serra Cedro in brazilian semi-arid]. Abstract: Participatory evaluation allows us to infer that the agricultural systems need to be improved and what knowledge can promote increments, thus aimed to evaluate different production systems in the Community Pé de Serra Cedro, Sobral, state of Ceará, Brazil, using participatory methodology with local farmers on soil properties and health of crops. The production systems evaluated were four, with the following descriptions: traditional system: planting annual crops, with burning area to 3 years; traditional system + manure; traditional system + manure + Leucaena leucocephala; and scuffed agroecological system. Inserting soil practices such as manure application and implementation of incresead legumes traditional production systems in semiarid region, even in short-term assessment. The use of agroecological scuffed differed for soil propertie sand health of crops over traditional managements with value 8.6 and 8.4 to soil and plant indicators, respectively.

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The Jaíba Irrigated Perimeter is a large irrigated agriculturearea, located in the region Forest Jaíba between the SãoFrancisco and Verde Grande rivers, in the Brazilian semi-arid region. In 2014, irrigators thisthe region face losses in theinterruption of new plantings in irrigated areas due to water scarcity. The objective ofthis study is combine the modelto estimate the Monteith BIO with the SAFER algorithm in the case of obtaining ET, to analyze the dynamics of naturalvegetation and irrigated crops in water scarcity period. For application of the model are necessary data frommeteorological stations and satellite images. Were used 23satellite images of MODIS withspatial resolution of 250mand temporal 16 days, of 2014 year. For analyze the results,we used central pivots irrigation mask of Minas Geraisstate, Brazil. In areas with irrigated agriculture with central pivot, the mean values of BIO over the year 2014 were88.96 kg.ha-1.d-1. The highest values occurred between April 23 and May 8, with BIO 139 kg.ha-1.d-1. For areas withnatural vegetation, the average BIO was 88.34 kg.ha-1.d-1with lower values in September. Estimates of ET varied withthe lowest values of ET observedin natural vegetation 1,91±1,22 mm.d-1and the highest values in irrigated area isobserved 3,51±0,97 mm.d-1. Results of this study can assist in monitoring of river basins, contributing to themanagement irrigated agriculture, with the trend of scarcity of water resources and increasing conflicts for the wateruse.

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In this study, we investigated the different responses of Spondias tuberosa (umbu) trees, which grow in two different ecological life zones in northeast Brazil: tropical wet and tropical arid ecosystems. We evaluated the responses of plants grown under humid and dry conditions by measuring the photosynthesis, water status, fluorescence parameters, carbon isotopes and antioxidant system activity. The higher net photosynthesis values were recorded contemporaneously with the lower VPD values. The highest internal-to-ambient CO2 concentration and the absence of typical changes in the fluorescence parameters suggested an onset of a nonstomatal limitation in the photosynthesis. Our results showed that umbu plants can adjust their antioxidant activity during the dry season as a defensive strategy against the deleterious effects of water stress. This evidence is supported by the observed modifications in the pigment concentrations, increased accumulation of hydrogen peroxide and malondialdehyde, high levels of electrolyte leakage, increased antioxidant activity, and decreased carbon isotope discrimination in the umbu trees during the dry season. Supported by multivariate analysis of variance, significantly effect of interaction between categorical months of collect and location predicts a strong ?dry season effect? on our dataset. Taken together, our data show that umbu trees grown in a wet tropical environment are more susceptible to drought, as compared with their tropical arid counterparts.