The Irrigation

Have serious decurrent problems of the application of herbicidas in irrigaopor flooding; in the irrigation for ridge, the carreia applied water, deherbicidas, beyond fertilizing, defensivose sediments. Also it can occur of slower form, by means of the subsurface lenolfretico, that receives fertilizers, defensives and herbicidas dissolved in the applied water. This contamination to podeser aggravated will be had leaves soluble in the ground, therefore, to if infiltrating, the water you leave jcontendo them applied in the farming, still you leave will dissolve them the ground, becoming more harmful. The contamination of the underground water is well slower. The necessary time percolao until the underground sheet increases with the decrease of the alone permeabilidadedo and with the depth of the sheet. To reach a fretico sheet situadoa about 30 mde depth, depending of the permeability of the ground, the 50anos can be necessary de3. There a serious problem inhabits, therefore much time after only is that quea will be known underground water comes being poluda; this problem if aggravates the sosais pollutants dissolved, nitrates, pesticides and metals heavy. Previous a geologic study it can disclose concentration of you leave soluble noperfil the ground and to indicate the areas most favorable, that is, with minor potencialde contamination of the hdricos resources.

How much bigger to the losses for percolaoe for superficial draining in the irrigation, greaters will be the possibilities decontaminao of the sources and the underground water. One becomes necessary, cadavez more, to dimensionar and to manejar the systems of irrigation with bigger efficiency, as well as correctly dosing fertilizers, herbicidas and defensives. In accordance with IBGE (1993), 96% of the water distributed in Brazil is analisadae receives some type of treatment, as filtration and addition of chlorine and fluorine. Of 25% of the domiciliated population of the country in agricultural areas, only 9.3% have redede water supply, 57.9% use water of well or spring and 32.8% tmoutra supplying form.