Nitrogen Release Associated with the Decrease in Soil Organic Matter in Newly Cultivated Soils

A marked decrease in soil organic matter occurs during the first years following the cultivation of virgin soils. The purpose of this work is to study the release of nitrogen, associated with this process. Technically, this was achieved by a series of comparisons between cultivated plots and adjacent virgin soils. It was found, that in the area under study, the decrease in soil organic nitrogen was rather fast and a steady state was apparently achieved during the first few years. The amount of nitrogen released during this process are up to 9 tons of N/ha. The amount of nitrogen released is linearily related to the initial organic nitrogen content of the soil. In regions where large areas of newly cultivated fields are found, this process may be a major factor responsible for nitrate enrichment of the drainage water.