USO DE ÁGUAS RESIDUÁRIAS E FERTILIZANTES ORGÂNICOS NA CULTURA DO FEIJÃO-CAUPI (Vigna unguiculata (L) Walp.) E NA FERTILIDADE DO SOLO

Abstract

The culture of the caupi-bean is a source of human feeding, it is used as a green manuring and forage plant and represents an important alternative for the socioeconomic growth of the North s and Northeast s Regions of Brazil , considering that it adapts itself to the conditions of drought of the Northeast and the high humidity of the North of the country. The use of residual treated waters, besides being a solution economically viable, it is also environmentally maintainable, because it is an effective form of control of the hydric pollution and an alternative to reduce the waste of fresh water in the irrigation process, taking into consideration that, in the world, 70% of the water from the rivers, lakes and aqüíferos is destined to this practice. The objective of the work was to evaluate the use of residual treated waters in the production of caupi-bean (Vigna unguiculata (L.) Walp.) and the comparative study with the organic fertilizers. The experiment was accomplished in the facilities of the Agricultural School Assis Chateaubriand/UEPB, municipal district of Lagoa Seca - PB, middle region of the Paraiban Rural and microregion of Campina Grande-PB. The experimental delineament was made, by chance, in blocks, with three ones, each one with 7 treatments and 5 experimental unities and each unity containing three plants. Each experimental unity was formed by a plastic sack, filled out with 10kg of soil. The used treatments were: Treatment (T1): Absolute Testimony (natural soil);(T2): treated drainage originated from a reactor UASB(Upflow Anaerobic Sludge Blanket);(T3): Treated drainage originated from Pond of Polishment;(T4): treated drainage originated from the reactor Chicanas;(T5): Manuring with vegetable remains; (T6): Manuring with composition of the manure; (T7): Manuring with composition of the sewer mud. The results were submitted to the Analysis of variance to diagnose meaningful effects and to the contrast of averages to the assessment of meaningful differences among the treatments. The organic treatments besides being the most productive also had superior indexes in relation to the number of grains and number of green beans. The organic treatments also were indicated as superiors in the production of dry matter, peels, leaves and stem. The values of nitrogen analyzed in the different parts of the caupi- bean, were, in general, also larger in the treatments T5,T6 and T7. The largest tenors of phosphorus in the grains corresponded to those treatments of sanitary nature. There was an increment of the electric conductivity of the extract of saturation of the soil for the treatments of sanitary nature and no increase in the potassium concentrations was proven, calcium and magnesium in the soil, as for the treatments of sanitary nature as for the organic ones after the crop of the plantation. The tenors of phosphorus in the soil were high but with an outstanding supremacy in the treatments which received vegetable rests, compound of bovine manure and sewer s mud. In general, the treatments elevated the saline concentration of the treatments, but not in levels which may commit the caupi-bean s performance.