Influence of siderates on soil fertility

Abstract

The aim is to study the influence of different types of postharvest green manure crops on soil fertility indicators. The research was supposed to study the effect of growing postharvest greens: winter wheat, spring barley, peas and winter oilseed rape on soil fertility: humus content, alkaline hydrolyzed nitrogen, mobile phosphorus, exchangeable potassium, soil reaction and soil acidity. Experimental studies were conducted during 2018–2021 in the conditions of FG "Zorya Vasylivka" Tyvriv district of Vinnytsia region on gray podzolic soils. In the option without growing greens, the humus content was 2.30%. Growing green manures contributed to the increase of humus content in the soil during crop rotation by 0.11–0.14%. The content of humus increased the most in the variant of growing green peas and winter rape, and the least — in spring barley. In general, the highest humus content was found in the variant of growing green peas and winter rape — 2.44%, and the lowest — in the cultivation of spring barley green — 2.41%. The alkaline nitrogen content in the option without growing greens was 118 mg/kg. When growing greens, the content of alkaline hydrolyzed nitrogen in the soil increased by 1.7–7.1%. The alkaline nitrogen content in the option without growing greens was 118 mg/kg. When growing greens, the content of alkaline hydrolyzed nitrogen in the soil increased by 1.7–7.1%. The content of alkaline hydrolyzed nitrogen in the soil increased the most after growing green peas, and the least after spring barley and winter rape. The highest content of alkaline hydrolyzed nitrogen was found in the soil where green peas were grown — 127 mg/kg, and the lowest — after growing green barley green manure and winter rape — 120 mg/kg. The concentration of mobile phosphorus in the control variant without growing greens was 622 mg/kg and was the highest among all studied variants where greens were grown. In the variants with the cultivation of green manure crops, the content of mobile phosphorus in the soil decreased by 16.4–18.0%. The smallest decrease in the content of mobile phosphorus in the soil, compared to the option without the use of green manure, was found in the variant of growing green wheat green manure, and the largest decrease — in the variant of growing green barley green manure. The soil of the variant without growing green manure contained exchangeable potassium 156 mg/kg. The cultivation of greens contributed to the increase in the content of exchangeable potassium in the soil by 27.4–32.2%. The largest increase in the content of potassium exchange in the soil was found in the variant of growing winter rape green manure, and the smallest — in the cultivation of winter wheat. The reaction of the soil pH on the option without growing greens was 6.05 pH. Variants with green manure cultivation were marked by a decrease in the reaction value of the soil solution by 0.2–0.5 pH. This indicates acidification of the soil when growing greens. The greatest acidification of the soil is observed after growing green rape green manure, and the least — after spring barley green manure. The hydrolytic acidity of the soil in the variant without green manure cultivation and in the cultivation of winter wheat green manure was the same and amounted to 1.60 mg-eq./100 g. In other variants of green manure cultivation, the hydrolytic acidity of the soil increased by 3.0–7.0%. The largest increase in hydrolytic acidity was found in the variant of growing winter rape green manure, where the actual hydrolytic acidity of the soil was the highest and amounted to 1.72 mg-eq./100 g.