Ecological and Agrochemical Evaluation of Continuous Mineral Fertilizer Usage in Field Сrop Rotation

Abstract

Fertilizers have a significant influence on the forming of the circulation of substances and energy in soils, agroecological state of lands, as well as the quality of agricultural products. Fertilizers and ameliorants, as some of the most effective means of restoring soil fertility, have a considerable influence on the agroecological condition and agrochemical indicators of arable soils in the process of their agricultural usage. The article researched such ecological aspects of using mineral fertilizers as changing the chlorine content in soil solution, potassium, calcium and magnesium content in soil intake complex as well as gross sodium content in soil after continuous usage of fertilizers in field crop rotation. The experimental part of the work was done in continuous stationary experiment in the field rotation of grain and beet crops with a set of crops traditional for the region defined in 1964. It was defined that the chlorine of fertilizers does not produce stable compounds in soil and migrates a lot in its profile. Using fertilizers in field crop rotation in a dose of 45–135 kg of K2 O/ha does not contribute to chlorine increase in physiologically active 1.5 m deep soil layer. At continuous fertilizer usage, there have been essential changes in the ashed fertile soil in the composition of its intake complex – the number of calcium and magnesium exchangeables has decreased, which entails worsening of the physical and chemical qualities and as a result leads to decreasing fertility level. The research results have evinced that the ratio between magnesium and potassium in a soil intake complex drops to 2.6–3.6 as a result of continuous potassium with fertilizer usage, according to the checking data without fertilizer application it makes up – 4.2, which corresponds to optimal ratio of Mg : K = 2–5. Keywords: mineral fertilizers, exchangeable cations, chlorine, natrium, soil intake complex, environmental assessment