EFFECTS OF IRRIGATION AND AMELIORATION TECHNOLOGY ON MICROBIOLOGICAL AND ENZYMATIC PROPERTIES OF SOIL

The significant negative effects on the microbiological and enzymatic properties of typical chernozem located in the Northern zone of the Republic of Moldova were observed as a result of long-term irrigation with saline water. The stocks of microbial biomass in the 0-160 cm layer were of 8073,5; 5274,2 and 4486,9 kg ha(-1) in the fallow chernozem (natural standard), arable un-irrigated and arable irrigated chernozems respectively. A similar trend has been noticed in the vertical distribution of enzymatic activities. There was a 3,6 fold increase in the amount of humus-mineralizing microorganisms. A soil management with the application of wastes (sugar industry sugar lime, manure) created conditions for the improvement of the microorganisms' vital activity in the degraded chernozem. Microbiological and enzymatic soil parameters depended on the doses of sugar lime material and the content of Na+ in the absorbing complex. A scale for assessing the ameliorative status of irrigated soils and for developing national standards of soil quality was elaborated. The use of sugar industry waste (the reserve of five years) with manure 60 t ha(-1) has been recommended for the regeneration of microbial communities, immobilization of enzymes and improvement of soil quality.