Abstract
The generalization of the results of 4 field experiments, the agrochemical and agrotechnical characteristics of which differed significantly, showed general and marginal increases in crop yields when using mineral fertilizers. The experiments were carried out in different soil and climatic zones of the Kurgan region: on heavy loamy ordinary chernozem in one of the farms of the Almenevsky district and on 2 experimental fields of the Kurgan Research Institute – Central (on medium loamy leached chernozem) and Shadrinsky (on heavy loamy leached chernozem). Type of tillage: in 3 experiments – plowing and crop rotation, in 4th – permanent wheat on a stubble background. Phosphorus fertilizer gave high yield increases on backgrounds with a content of mobile P2O5 in a layer of 0–20 cm of soil from 30 to 50 mg/kg, with a content of 74 mg P2O5/kg it had little effect. When testing doses of nitrogen and phosphorus, their first level provided the largest and best-paid marginal increase in comparison with the increments from the following doses of fertilizer. The fertilizer had a positive effect on wheat yield and grain protein content. The achievement of the 3rd grade of grain quality was attributed to 60–90% of the years in the experimental versions with 40–50% of the years in the control. It can be quite definitely concluded that on backgrounds with a soil content of 74 mg P2O5/kg, only nitrogen fertilizer should be used; the nitrogen dose should be reduced to N40–50, the phosphorus dose to P15–20 using a near-sowing method of applying phosphorus fertilizer. Under these conditions, the profitability of the fertilizer increased to 45–73% compared with low and negative indicators in other variants.