THE ROLE OF FERTILISERS IN CONSERVING SOIL FERTILITY PUBLISHEDGorica Cvijanović, Ivica Djalović, Miladin Vesković, Drago Cvijanović
In order to maintain the existing level of the soil fertility, nutrients taken out are necessary to be returned to the soil by the yield. It is allowed to use all available sources in the course of returning of nutrients taken out. This paper presents results gained on the effects of fertilisation methods on the yield of the maize hybrid ZP SC 704, then on the dynamics of organic matter in the soil and the abundance of important systemic and physiological groups of microorganisms that provide soil biogeny. The following fertilisers were applied in the maize crop: mineral fertilisers in the rates of 332 and 664 kg ha -1 , ploughed down stover, as an organic matter (each year in the amount of 8,000 kg ha -1 ), combinations of mineral nitrogen and stover ploughed down, manure in the amount of two-three animal units per hectare. It was determined that observed parameters (amount of organic matter, degree of organic matter transformation into soil organic matter, the abundance of certain systemic and physiological groups of microorganisms), as well as, the nitrogen content, were significantly increased in variants with ploughed down organic matter and mineral fertilisers. According to obtained results it was determined that a long term application of mineral fertilisers did not significantly affect the changes of the organic matter content in the soil nor it decreased the soil productivity. A long term application of organic fertilisers in the form of stover and manure very significantly increased the content of organic mater and elements of biogeny in the soil, whereby a positive effect of the combination of organic mater and mineral fertilisers was particularly pronounced. Such a method of fertilising in the crop production undoubtedly satisfies the fundamental principles of organic agriculture (organic food production with the ecological and economical effect).
soil; fertilisers; organic mater; nitrogen; microorganisms