Influence of Long-Term Fertilisation on Nitrogen Leaching

Abstract

The influence of mineral fertilization on the content of nitrogen in the soil profile, the soil solution, the lysimetric- and ground- waters was studied in a 20 year field experiment with maize (monoculture) in Bulgaria. The results show that, under fertilization rates estimated to cover 100-125% of the nitrogen uptake with the plant production, a nitrogen accumulation in the entire profile is observed. The long-term nitrogen fertilization with rates over 210 kg/ha leads to increased nitrate nitrogen in the soil solution and the lysimetric water, which is the precondition for its increased migration outside the root zone and subsequent nitrate pollution of the groundwater.