Effects of agricultural activities on water pollution with nitrates and pesticides in the Central Valley of Chile

abonos agua superficial chile chili contamination dairy farms eau souterraine eau superficielle engrais eutrophication eutrophisation exploitation agricole explotaciones agrarias farms fertilizers ganado granjas lecheras groundwater groundwater pollution irrigation livestock nitrate nitrates nitratos pedogenese pesticide pesticides plaguicidas pollution pollution de l'eau pollution de l'eau souterraine riego simulation soil genesis surface water water pollution