Nitrogen regime of soddy-podzolic soil with long-term use of different types and combinations of mineral fertilizers

Abstract

The purpose of the work is to study the effect of various types and combinations of mineral fertilizers on the fractional composition of nitrogen in soddy-podzolic soil in a long-term stationary experiment and compare it with a virgin analogue. The studies were carried out in 2016 and 2018 on the experimental field of the Perm Research Institute of Agriculture after harvesting barley in an eight-field crop rotation deployed on soddy-podzolic heavy loamy soil. The experiment scheme: without fertilizers: N90; Р90; К90; N90P90; N90K90; P90K90; N90Р90К90. To assess the effect of nitrogen, phosphorus, potash fertilizers and their combinations on the nitrogen regime of soddy-podzolic soil, the arable soil was compared with the virgin analogue. The nitrogen fund of soddy-podzolic soil of a long-term stationary experiment is represented by 64…71 % non-hydrolyzable and 17…22 % hardly hydrolyzable forms of nitrogen. Long-term use of various types and combinations of mineral fertilizers did not significantly change the ratio of nitrogen fractions characteristic of virgin soils of this type. Nitrogen fertilizers, both with one-sided application and in combination with potassium chloride (N90К90) and superphosphate (N90P90), contributed to an increase in the total nitrogen content in the arable soil layer by 10…20 % relative to the control, mineral nitrogen compounds - by 2…3 times. Unilateral application of potash fertilizer provided an increase in the content of total nitrogen in the soil by 12 %, the introduction of superphosphate did not have a signi cant effect on the nitrogen regime of the soil. Long-term use of complete mineral fertilizer (N90P90K90) only in this way: (N90P90К90) contributed to maintaining total nitrogen at the level of virgin soil - 1490 mg/kg. Long-term unilateral application of nitrogen fertilizers increased the content of nitrate nitrogen in the soil over the entire meter layer by 1.5-2.5 times, ammonium - by 1.5-14.6 times. The reserves of mineral nitrogen in the variants N90P90, N90K90, and N90P90K90 in the 0-20 cm layer increased 2-3 times, in the 0-100 cm layer - 2 times relative to the control variant.