Optimization of nutrition of crops in conditions of physicochemical degradation of acid soils

Abstract

Goal. To study and to identify features of optimization of crop nutrition during physicochemical degradation of acid soils. Methods. Field, laboratory, computational, mathematical, and statistical. Results. Results are given of researches in the influence of agrochemical load on gray forest soil with increasing doses of fertilizers (in combination with measures of radical chemical reclamation and without them) received during 2016–2019. It is established that the use of intensive fertilizer systems without radical chemical reclamation leads to the deterioration of the physicochemical properties of gray forest soil. On the background of reducing the aftereffects of radical chemical reclamation for 10–13 years, the annual application of a dose of alkaline earth elements, taking into account the physiological characteristics of the culture (average 11.4 and 4.6 kg/ha of calcium and magnesium, respectively) ensures for 10–12 years close to neutral reaction, and on the 13th year of application — the slightly acidic reaction of the soil solution. Besides, the content of exchangeable Ca and Mg in GVK increases slightly, it increases to 6.71–7.00 mg·eq/100 g of soil. Conclusions. The use of a dose of mineral fertilizers on gray forest soil, which is calculated according to the species genotypic ratio (SGR) of elements in the biomass of the culture on the background of application of lime, optimizes crop nutrition, physicochemical properties of the soil, reduces the dose of phosphorus and potassium and toxic action of H+ and Al3+. The optimal combination of N, P, K, Ca and Mg (216 kg/ha in the ratio of 1:0.4:0.5:0.3:0.1) in combination with seed inoculation with nitrogen-fixing and phosphorus-mobilizing bacteria provides an increase of productivity of the grain crop rotation to 5.45 t/ha g.p., and payback of 1 kg act. mat. of fertilizer applied to 15.6 kg g.p. Physicochemical degradation of acid soils at the application of high doses of nitrogen fertilizers can be partially prevented by saturation of the soil absorption complex with exchange cations of alkaline earth metals, supplementing the fertilization system with small doses of Ca and Mg, which are calculated according to the recommended dose of nitrogen, limited on acidic soils.