Mineral nitrogen dynamics after the incorporation of Winter cover crops

In the plot trial established at the Rimski Sancevi Experiment Field of the Institute of Field and Vegetable Crops, the influence of different cover crops (forage pea, wheat, and mixture wheat + pea) and mineral N fertilizers (N1 40 kgN/ha and N2 80 kgN/ha) on NO3-n dynamics in soil has been investigated. Winter cover crops were incorporated in spring 2005 and 2006 and after that Sudan grass was sown. The highest content of NO3-M in soil at the end of vegetation period, and the highest yield was measured on the winter forage pea treatment. On the treatments with wheat and crops mixture (wheat + pea) content of NO3-N in soil during the vegetation period was lower in relation to control and other treatments. A positive significant correlation was confirmed between the content of NO3-N in soil at the end of vegetation period and yield of Sudan grass.