The Number of Actinomycetes and Soil Fungi in Mineral and Organic Fertilisation Conditions

Abstract

At the Experimental Field of the Faculty of Agronomy in Cacak over the 1996-1997 period investigations were carried out on the effect of increasing nitrogen rates (N1- 30 kg/ha, N2-60 kg/ha and N3-90 kg/ha), standard P and K amounts (75 kg/ha) and organic fertilisers (solid manure – 45 t/ha and liquid manure – 80 t/ha) on the number of actinomycetes and fungi in the soil under spring oats. The trial was set up in a randomised block design with three replications. The investigations showed that the applied fertilisation variants, sampling periods and study years had affected the number of microorganisms examined. Mineral fertilisers had caused a reduction in the number of actinomycetes. The N3 variant had the highest inhibitory effect of all the variants of the mineral fertilisers studied. The inhibitory effect of the fertilisers used was more pronounced in the second sampling period. Asmopposed to that, the total number of soil fungi grew as the mineral nitrogen rate increased, particularly in initial phases of the growth season. Furthermore, the organic fertilisers used caused a reduction in the number of actinomycetes, with the exception of the variant with liquid manure in the first sampling period. As opposed to that, the application of these fertilisers brought about an increase in the fungi number. The number of actinomycetes was higher during 1996 and that of fungi was reported to be greater during 1997.