Transfer of nitrogen and phosphorus to surface water in a watershed with agriculture and intensive livestock production in Southern Brazil

Viviane Capoane Tales Tiecher Gilmar Luiz Schaefer Lucas Henrique Ciotti Danilo Rheinheimer dos Santos About the authors

In order to evaluate the impact of agricultural activities on aquatic ecosystem, the concentration of nitrate and soluble phosphorus (P) in the stream water were assessed in a rural watershed under intensive agriculture and livestock production in southern Brazil. Water samples were collected at 11 points along the drainage system in three different periods. Additionally, daily collections were made during 30 days in the middle and at the outlet of the watershed. Nitrate and soluble P concentrations were higher in the points closer to the more anthropized areas and pig farms. The soluble P concentration changed substantially according to the rainfall events, while nitrate concentration show little change with rainfall regime. The high nitrate and soluble P concentrations were attributed to poor management of the intensive livestock activities undertaken in the watershed

animal waste; intensive pig farming; human disturbance; eutrophication

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