Influence of using fertilizers on fertility indices of sod-podzolic soils and productivity of short-term crop rotation of Polissya

Abstract

The influence of litter manure and straw as fertilizers in pure form and in combination with manure, green manure and mineral fertilizers on the content of humus and basic nutrients in sod-podzolic soil has been studied. A significant effect on the change of humus content on sod-podzolic soils depending on fertilizer systems has been established. The highest indicators of humus content in the soil were found in the variants with 40 t/ha of manure, 0.97–1.14% and 1.17–1.23%, respectively, and straw 4 t/ha in combination with lupine green manure — 0.94–1.15% and 1.16–1.25%. The most significant increase in humus content per rotation was observed in sidereal crop rotation, against the background without fertilizers the indicator increased by 0.05–0.29%, against the background of N40P40K120 application — by 0.03–0.21%, in crop rotation — 0.05–0.19% and 0.01-0.09%, respectively. Analyzing the dynamics of the content of easily hydrolyzed nitrogen, it was found that the greatest growth both at the beginning and at the end of crop rotation provided options with the introduction of 40 t/ha of manure (+69…+85 mg/kg of soil), 4 t/ha of straw with half dose of manure (+63…+82 mg/kg of soil) and straw with green manure (+71…+80 mg/kg of soil). The application of manure, straw and plowing of green manures contributed to the increase of the content of mobile phosphorus compounds from 9 to 69 mg/kg of soil on the background without fertilizers and 38 to 67 mg/kg of soil on the background N40P40K120. The combination of straw with manure and straw with green manure for the application of mineral fertilizers helped to increase the content of mobile phosphorus compounds to the level recorded in the variant for the application of 40 t/ha of manure, and in some versions of the experiment even exceed it. It was found that the deficit-free and positive balance of potassium for rotation of crop rotation and sidereal crop rotation was provided by variants with 4 t/ha of straw in combination with 20 t/ha of manure and 4 t/ha of straw in combination with lupine green manure against N40P40K120. Balances and productivity of arable land use in short-rotation crop rotations of Polissya are calculated. In crop rotation, the humus balance is negative for the alienation of lupine green mass for fodder. Variants with application of 10 t / ha of crop rotation area of manure (–0.03 t/ha) and 1 t/ha of straw with half dose of manure (–0.1 t/ha) on the background of N35P35K85 application allowed to get as close as possible to the deficit-free balance of humus. In sidereal crop rotation, a positive balance of humus is observed with the application of 10 t/ha of manure (+0.21…+0.29 t/ha), 1 t/ha of straw in combination with 5 t/ha of manure, 22 t/ha) and 1 t/ha of straw in combination with green manure (+0.09… +0.18 t/ha). Close to the deficit-free balance of humus is the option with the introduction of 1 t/ha of straw in its pure form. An alternative to manure in Polissya should be the use of straw in combination with green manure (including lupine), which will help preserve and reproduce the humus content in the soil, improve the balance of nutrients and increase the productivity of arable land in crop rotations.