Influence of cultivate inerventions and climatic factors on dynamic of inorganic nitrogen forms in soil

In the field trial in 2002 and 2003 was investigated contents and dynamic of inorganic nitrogen forms (ammonium and nitrate nitrogen) in soil. Monitored factors were fertilization, tillage systems, year, temperature and moisture of soil. This experiment was realized on experimental bases of Slovak University of Agriculture in Nitra - Dolna Malanta at the corn (Zea mays) as arable crop, with pea as before-crop and white mustard as intercrop. In the field trial was used two tillage systems, B1 - medium depth ploughing and B2 - shallow ploughing, with two fertilization variants, PH - industrial fertilizers and 0 -without fertilization. The soil samples were taken in from depth of soil profile of 0.0-0.3 m. In taken of soil samples were determined the contents of inorganic nitrogen forms (in the 1% leachate of K2SO4) by color method with acid phenoldihydrosulphate for nitrate nitrogen a color method with Nessler test solution. From the obtained results we can confirm, that the contents of ammonium nitrogen in soil were affected by several factors. Average content of ammonium nitrogen in the whole research period was 5.67+/-1.11 mg per kg (5.12 mg per kg in the first year, 6.21 mg per kg in the second year). Coefficient of variance was 19.60%. In May were found out the lowest average contents. It relatives with favourable conditions for nitrification process in this month what incurred decrease of ammonium nitrogen contents in soil. In July and September 2003 were found out the higher contents of N-NH+ in PH variants, where industrial fertilizers were applied. In the rest of sample times ammonium nitrogen had a steady dynamic. Nitrate nitrogen was affected by less number of factors. Its average contents in the whole research period was 10.27+/-7.71 mg per kg (5.66 mg per kg in 2002 and 14.87 mg per kg in 2003) with coefficient of variance 75.11%. Dynamic of nitrate nitrogen was more marked then dynamic of ammonium nitrogen. In dynamic of nitrate nitrogen dominated spring maximum in May especially. Contents of N-NO3 decreased in the summer season in the first year especially. In the second year they sustained of May trend. Higher contents of nitrate nitrogen were found out in variants with industrial fertilizers in 2003 alike an ammonium nitrogen.