POSSIBILIDADES E LIMITES NA GESTÃO DA ÁGUA EM SITUAÇÃO DE ESCASSEZ : PRÁTICAS DE PRODUTORES AGRÍCOLAS NA BACIA DO PAJEÚ – PERNAMBUCO

Situada nas mesorregiões do Sertão Pernambucano e do São Francisco Pernambucano, a bacia do rio Pajeú tem clima semiárido, com médias pluviométricas anuais inferiores a 800 mm, concentradas nos meses de fevereiro, março e abril, e apresenta deficiência hídrica de nove meses. Na área da bacia a atividade econômica predominante é a pecuária, seguida da agricultura desenvolvida predominantemente por pequenos proprietários e agricultores familiares para a sua subsistência, que torna-se limitada pelo fator escassez hídrica. A produção agrícola é comprometida e reduzida em função da baixa disponibilidade hídrica e ausência de políticas efetivas para a mudança do quadro de pobreza instalado na região onde falta de acesso a água permanece sendo a grande mazela da população do semiárido, sendo a boa gestão da água essencial para a elevação da qualidade de vida local. Na porção setentrional da bacia, a ação do Projeto Dom Helder Câmara, acordo de empréstimo entre o Governo Brasileiro/Ministério do Desenvolvimento Agrário e o Fundo Internacional para o Desenvolvimento Agrário/FIDA, tem apontado na direção das possibilidades de produção agrícola e convivência com as condições de semiaridez, direcionando ações como a instalação técnicas simples de captação de água - cisternas, cisternas calçadão, barragem subterrânea. Portanto, este trabalho tem como objetivo verificar na área de atuação do projeto Dom Helder, na porção norte da bacia do Pajeú como os agricultores familiares tem viabilizado a produção agrícola inclusive com diversidade de produção de subsistência em função da instalação de técnicas de captação e armazenamento

Metastability in Josephson transmission lines

Thermal activation and macroscopic quantum tunneling in current-biased discrete Josephson transmission lines are studied theoretically. The degrees of freedom under consideration are the phases across the junctions which are coupled to each other via the inductances of the system. The resistively shunted junctions that we investigate constitute a system of N interacting degrees of freedom with an overdamped dynamics. We calculate the decay rate within exponential accuracy as a function of temperature and current. Slightly below the critical current, the decay from the metastable state occurs via a unique ("rigid") saddlepoint solution of the Euclidean action describing the simultaneous decay of the phases in all the junctions. When the current is reduced, a crossover to a regime takes place, where the decay occurs via an "elastic" saddlepoint solution and the phases across the junctions leave the metastable state one after another. This leads to an increased decay rate compared with the rigid case both in the thermal and the quantum regime. The rigid-to-elastic crossover can be sharp or smooth analogous to first- or second- order phase transitions, respectively. The various regimes are summarized in a current-temperature decay diagram.Comment: 11 pages, RevTeX, 3 PS-figures, revised versio

Growth Characteristics of Kikuyu Grass with Different Sources and Doses of Phosphorus

Growth is defined as the increase in size, volume and mass as a function of time. Growth analysis allows evaluating the final growth of the plant as a whole and the contribution of the different organs in total growth (Benincasa, 1988). The experiment had as objective to evaluate specific leaf area (SLA), leaf area per unit of leaf DM, leaf area ratio (LAR), leaf area per unit of whole plant DM, leaf weight ratio (LWR), leaf weight per unit of plant weight, leaf area index (LAI), leaf area per unit of soil area, leaf/stem ratio (LSR), leaf weight per unit stem weight, of 35 days old kikuyu grass with different sources and doses of P

Soil microarthropod populations under crop-livestock-forestry integration in Amapá savanna - Brazilian Amazon.

The soil fauna presents a huge potential as a bio-indicator of soil quality, this because its abundance and wealth are susceptible to changes in their management and use. The CLF integration aims at synergistic effects among the components in de agroecosystem. Upgrading biodiversity approving new niches and habitats to meso-orgnisms, very important for soil enrichment and recycling of nutrients

Seasonality of Forage Production of Coastcross-1 with Different Sources and Applications of Phosphorus

Brazil presents high potential for meat production from pastures. However, the feeding of ruminants depends on the conditions and the climate. Approximately 80% of the annual production of dry matter (DM) occurs in the period October to March (spring - summer). In the autumn and winter production is low associated with high humidity and low temperatures in the south and low rainfall in the tropical north. The situation is exacerbated by inadequate management practices and low soil fertility, particularly low levels of phosphorus (P). The objective of this experiment was to evaluate the seasonality of production of DM of coastcross-1 (Cynodon dactylon) with different sources and applications of P for two consecutive years