Dynamics of nitrate accumulation in soil as a function of inorganic and organic fertilization

Attila Dunai, Zoltan Toth

University of Pannonia Georgikon Faculty, 16 Deak Ferenc Str, Keszthely, Hungary, H-8360, www.georgikon.hu, [email protected]

Abstract

The study was carried out in a long-tem field experiment set up in 1983 at the experimental site of the University of Pannonia Georgikon Faculty, Keszthely, Hungary. The experimental factors were the increasing rates of mineral N fertilizer and the complementary applied organic fertilizers (NPK: inorganic fertiilizers only, NPK + FYM: inorganic fertilizers and farmyard manure, NPK + St + GM: inorganic fertilizers, straw and green manure ploughed-in). Soil was a Ramann-type brown forest soil (Eutric Cambisol), with low humus content. The annual precipitation of the year of study was relatively high (877,1 mm).The amount of precipitation in the studied period (May-September 2014) was also high (557,1 mm).

Sampling of nitrate was carried out in the 0-1 m soli layer in 5 sublayers (0-20, 20-40, 40-60, 60-80, 80-100 cm) and in ten different dates during the growing season of corn in 2014.

The results show limited nitrate leaching in the first half of the growing season until a depth of 60 cm. No leaching of NO3- was measured in the deep soil layers below 60 cm. By the end of growing season soil became exhausted due to the nitrate absorption of the crop. Additional applied organic fertilizers resulted in higher nitrate values in the 0-60 cm soil layer at the first sampling date compared to the NPK plots, but these values reduced by the end of season without leaching.