INFLUENCE OF VARIOUS FERTILIZER SYSTEMSON THE HUMUS STATE OF SODDY-PODZOLIC SOILS OF THE PSKOV REGION
The article presents the results of long-term field experiences in studying the influence of mineral and organic fertilizers on fertility indicators of soddy-podzolic soils in the conditions of the Pskov region. Organic crop fertilization systems (70 t/ha manure; peat equivalent to 70 t/ha manure; waste water sludge equivalent to 70 t/ha of manure) on soddy-podzolic light-loamy soil in 2003-2009, the humus growth rate was 0.03% per year. Organic and organomineral systems of fertilization of crops in crop rotation in doses - manure 30 t/ha and manure 30 t/ha+ N60P60K60 on soddy-podzolic sandy soil in 2009-2015 contributed to an increase of humus content by 0.05%per year. It has been found that in the long-term use of organic and organomineral fertilizer systems of soddy-podzolic soils, the thickness of the arable layer of medium and well-cultivated soils increases from 9 to 20 cm. In field tests in crop rotation on the control version there was a decrease in humus content on average from 1.92 to 1.80%, by 0.12% abs on light-loamy soil and from 1.95 to 1.72%, i.e. by 0.23% abs on sandy soil.