Effect of grown plants on drainage water quality

Abstract

In 1999-2003, the investigations were carried out in Juodkiškis study object of Water Management Institute of Lithuanian University of Aqriculture. Study scheme is composed of three treatments: treatment I - slurry applied, treatment II - mineral fertilizers applied, treatment Ill - no fertilization. Test field is drained, drain spacing is 15 m, draining depth is 1.2 m. During the crop rotation the following plants were grown: spring wheat with undercrop, red clover (1st year of use), red clover (2nd year of use), sugar beet, and spring rape. II 10 objective of the studies was to determine the effect of cultivated crops on drainage water quality. As the study results have show, N,^ concentrations contained in drainage water increased due to higher fertilization rates and inorganic nitrogen accumulated in the soil. Neither fertilization nor amount of mobile phosphorus contained in the soil made any effect on Ptotal concentrations in drainage water. In arable land, Ntotal concentrations contained in drainage water were 2.3 times higher than those in drainage water of the field, where ml clover was grown. Ptotal concentrations were higher in the field with red clover. According to the rates determined in Lithuania, drainage water is not polluted with phosphorus, while average annual Ntotal concenfrations exceeded the maximum allowable (MAC) when spring wheat with undercrop and sugar beet was grown.