Effect of nitrogen fertilizer on growth of seeded grassland dry biomass in process of deposol: Biological reclamation

Abstract

The paper presents the results of a three-year trial (2011-2013) on the variability of the yield of dry overhead biomass of the seeding grassland depending on the application of N fertilizer.Three grass-leguminous mixtures and one grass mixture has been researched (total of ten species of grass and leguminose) in the process of the biological phase of the reclamation of the technogenic soil, the type of Deposol. The research has been conducted on the Deposol at internal disposal area for overburden from Raskovac open pit in Stanari coal mine(Republic of Srpska, Bosnia and Herzegovina).The seeded grasslands stand for the significant driving force of pedogenetic processes in new soil reclamation. There are four treatments of doses of N fertilizers in application (N1 144, N2114, N3100 and N4130kg/ha). N fertilizer is used in basic and supplemented grassland nutrition. The application of N fertilizer in the seeded grassland has shown significant variation of dry biomass. The results have varied by years, different compositions and particular cuttings. In 2011 the N effect was lower in the first than in the second cutting. In 2012 and 2013 the N effect was better in the first cutting. The highest effect of N fertilizer is found with the TDS-3 mixture in every research year ( x 1 kg N = 36.32 kg in 2011, x 1 kg N = 97.67 kg in 2012 and x 1 kg N = 115.93 kg of biomass in 2013). The highest effect of 1 kg N on the biomass yield is calculated at TDS mixture at N3 treatment in the first cutting in 2013 (190.12). The lowest effect of 1 kg N on the biomass yield is calculated at the TDS-1 composition at treatment N3 in the first cutting in 2011 (10.00). The better effect is achieved with the smaller dose of N fertilizer. This is the starting point in any future standardization of fertilizers when fertilizing the seeded grasslands in the process of Deposol reclamation.