Characteristics of the Nitrate leaching in intensive farming areas

Abstract

The increase of the nitrate concentration (NO₃^-) in the water of underground drainage, and the increase in the contamination of the water table due to high rates of nitrogen fertilizers applied have occurred practically all over the world. NO₃^- leaching in agricultural areas is enhanced by the physical properties of the soil, by intense agricultural practices and by the high appropriation of water used in irrigation. The concentration of nitrate on water is a potential cause of damages to man and to the environment. Among the most common problems observed are the dysfunction of the thyroid gland, the production of nitrosamines, which generally cause cancer, and a decrease on the capacity of blood to transport Oxygen, also known as metahemoglobinemia, besides the impact on the various plants and environments. The increase in the leaching associated with the risks and impacts of the nitrate as soil and water pollutant shows the necessity of care on the nitrogen fertilizer management, due to the wide implications on the human and animal lives, besides the economic and environmental questions involved. The research on the nitrate leaching area has enabled the generation of new alternatives of agricultural management, with reduction of the impacts of the crop in intensive systems over the contamination of water sources; however, it is necessary to enlarge the knowledge and the generation of new technologies to apply in the intensive farming areas aiming a most appropriate management of the nitrogen in the system water-soil-plant.