Avaliação da potencial contaminação das águas superficiais e subterrâneas por agrotoxicos em áreas de produção de uva para exportação no Vale do São Francisco.

O sistema produtivo de uva irrigado do Vale do São Francisco é caracterizado pela ampla utilização de agroquímicos. Por meio da lixiviação e do escoamento superficial da água, os agrotóxicos podem ser transportados, prejudicando a qualidade das águas subterrâneas e superficiais. As propriedades físico-químicas dos agroquímicos bem como as características dos solos são determinantes para essa movimentação. Portanto, o conhecimento destes atributos, bem como adequação do manejo dos solos a estas propriedades, pode ajudar a minimizar o impacto ambiental. Em vista disso e para avaliar a qualidade dos corpos hídricos da região, foi realizado um estudo do potencial de contaminação dos agrotóxicos aplicados no cultivo de uva para exportação no Vale do São Francisco, empregando-se para estas análises os índices de GUS e GOSS. Como resultado, obteve-se uma lista discriminando quais apresentam maior risco de contaminação para os recursos naturais. No geral, constatou-se que os agrotóxicos utilizados oferecem baixo potencial de contaminação das águas subterrâneas e médio a alto potencial de contaminação das águas superficiais

Comportamento produtivo do feijoeiro comum sob deficiência hídrica.

Este trabalho teve como objetivo identificar genótipos de feijoeiro comum mais tolerantes à seca

STUDY AND VALIDATION OF MESHES IN TURBULENT ISOTHERMAL PROBLEMS OF NATURAL CONVECTION IN FLAT PLATES

The study of natural convection on flat plates is of great interest in the areas of Engineering, both for the simplicity of geometry and the wide variety of applications. In the study and definition of a numerical model, an ideal mesh configuration is the one that best represents physically, with minimal numerical influence and with the lowest computational cost, the problem addressed. The influence of two mesh configurations (non-uniform staggered and entirely uniform), at different refinement levels, was studied to evaluate natural convection heat transfer rates in flat plates of AR = 5; in isothermal conditions, in turbulent regime with the κ−ω SST RANS model and using free and open-source software OpenFOAM®. The physical-numerical methodology applied, and the numerical results obtained were validated from experimental results in the literature. The non-uniform staggered mesh configuration proved to be more adequate in precision, and computational cost to the problem situation studied. The entirely uniform mesh proved to be infeasible due to the high number of elements and computational cost demanded

Efeito da aplicação de água salina do desenvolvimetno e comportamento fisiológico do coqueiro.

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\u3cem\u3eBrachiaria Spp.\u3c/em\u3e (Syn. \u3cem\u3eUrochloa Spp.\u3c/em\u3e) CV. Mulato Ii (Convert HD364) Mass Production Under Continuous Grazing in the Water/Dry Transition Period

In the transition period between the rainy and dry seasons there is decreased water, temperature and luminosity, reducing forage production and quality. Because of this variability in forage mass production, it is essential to quantify forage mass for use in planning and decision making about pastures management. The objective was to evaluate Brachiaria spp. (Syn. Urochloa spp.) cv. Mulato II (Convert HD364) growth, biomass production managed under continuous grazing with steers fed with protein supplement feed in-trough and on-ground during the seasonal transition period. The experiment was carried out in the Beef Cattle Sector of Jatai Federal University (UFJ), Brazil, from March to June 2020, in a completely randomized design, using 18 male Nellore steers at 24 months of age, with two animals per paddock. Variance analysis was performed by SAS software using the GLM procedure and time repeated measures with significance set to P \u3c 0.05. There was no significant difference between way of supplementation. In the rainy/drought transition period, Convert-grass produced 7,622 kg DM/ha and 1,995 kg DM/ha of leaf mass. The pelleted protein supplement can be used both in-trough or with onground because the method of feeding did not change the forage offered but the canopy was undergrazed which could biased the responses to the supply method evaluated