In conventional farming, intensive mineral fertilization is associated with several environmental impacts such as nitrate contamination of surface waters, which can cause negative effects on ecosystems and also on human health due to nitrate intake (either dissolved in water or in food).
A new experiment carried out by the Agricultural Research Service of United States Department of Agriculture (USDA-ARS) compared organic and conventional crop rotations and an organic pasture (bromegrass, fescue, alfalfa, white clover) system. The aim of this study was to quantify growing season subsurface drainage water flow, nitrate concentrations and loads for conventional and organic grain cropping systems from 2012 to 2014. The results obtained showed that nitrate loss via water in conventional cropping systems was nearly twice as high as that from the organic system. The researchers conclude that organic methods such as the application of composted animal manure and the use of forage legumes and green manures within extended cropping rotations can be used to reduce water pollution.
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