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Seasonal changes of nutrients in drainage water
Date Issued |
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2006 |
The paper analyzes the data about the changes of nutrient concentrations contained in drainage water in respect of the season of the year. The studies were carried out in a five-field crop rotation in Juodkiškis study object within the period of 1999 to 2003. As the study results have shown, the largest amount of Ntotal is leached in winter, while the leaching of Ptotal is more intensive in spring. Concentrations of N depend on fertilization and content of inorganic N in the soil, while the increase in P total concentrations depends on grown perennial crops. On the basis of the data collected within a 5-year period, it was determined that Ptotal concentrations never exceeded the permited limit (PL). Ntotal concentrations exceeded MAC when annual crops were grown and after clover field was ploughed up. Nutrient leaching much depends on the meteorological conditions. During the cold period of the year Ntotal leaching is more intensive when the air temperature is higher, while during the warm period of the year larger amounts of Ntotal are leached when the territory experiences more precipitation. Ptotal leaching depends only on precipitation in both warm and cold periods of the year.