The content and composition of organic matter of sod-podzolic soil when applying fertilizer mixtures based on sewage sludge

Abstract

Relevance. The organic matter of the soils of the Non-Chernozem zone requires additional sources of its replenishment, which can include sewage sludge (SS). The paper investigates the use of sewage sludge from Tver, introduced fresh into a mixture with additional organic substrates (sawdust, peat, straw) in the field crop rotation link.Methods. The experiment was carried out in the Tver region on sod-podzolic sandy loam soil in fourfold repetition. OSV was introduced as part of a total dose of a fertilizer mixture of 60 t/ha with additional organic substrates (sawdust, peat, straw) taken in different proportions (1:1, 1:2, 1:3) at the beginning of the experiment. The area of the experimental plot is 6 m2. Crops of the crop rotation link — mixture vetch and oat, winter rye, spring barley. The content of organic matter, its group and fractional composition were determined in soil samples according to the methods generally accepted in agrochemistry.Results. The introduction of SS together with additional substrates contributed to an increase in the amount of soil organic matter (1,38–1,5%) and its maintenance in the aftereffect at the level of 1,33–1,49%, in the control variant this indicator was 1,26% (the significance of differences p < 0,05). The studied fertilizers provided an increase in the share of GA-1 and a decrease in FA-1a. In comparison with the finished compost, fertilizer mixtures, in which the components were in equal proportions, were ahead of the comparison options in their effect. They also contributed to the highest increase in productivity of the crop rotation link among all the variants of the experiment (an increase in control — 61,1–68,2%). Compost provided an increase in productivity by only 37,9%.