Change of Ecological and Agrochemical Indicators of Soil Depending on Its Degree of Washing

Abstract

On poorly washed chernozems podzolized with hard loam, the humus content decreases by 12.9%, compared with unwashed soils. Low-washed chernozems podzolic had a content of easily hydrolyzed nitrogen by 13.3% less than unwashed. The content of mobile forms of phosphorus on slightly washed soils decreased by 51.1%. The content of mobile potassium on unwashed chernozem podzolic heavy loam was 34.9% higher than on weakly washed soil. Observations of chernozem podzolic heavy loam medium washed showed that the humus content decreased by 8.8% compared to slightly washed. The content of easily hydrolyzed nitrogen decreased by 14.3%. The content of mobile forms of phosphorus increased by 15.3%. The content of mobile forms of potassium increased by 42.9%. Hydrolytic acidity of slightly washed soil increased by 4.9%. The reaction of the soil solution - by 1.8%. The amount of absorbed bases increased by 11.4%. Medium-washed chernozem podzolic heavy loam had hydrolytic acidity 11.3% higher than slightly washed. The reaction of the soil solution was 1.7% lower. The amount of absorbed bases was the same. Changes in the agrochemical composition of podzolic heavy loam chernozem on unwashed and lightly washed soils showed that weak soil erosion leads to a decrease in humus, easily hydrolyzed nitrogen, mobile forms of phosphorus and potassium, increasing the value of hydrolytic acidity, and the amount of solute. The largest decrease in the content of mobile forms of phosphorus - by 51.1% and the smallest and almost identical decrease in the content of humus and easily hydrolyzed nitrogen - by 12.9-13.3%. The sum of absorbed bases increased the most among the indicators of acidity of chernozem podzolized heavy-washed slightly washed, in comparison with the unwashed one, by 11.4%, and the reaction of soil pH solution increased the least - by 1.8%. From the agroecological point of view, weak soil erosion causes deterioration of such soil fertility indicators as reduction of humus content, easily hydrolyzed nitrogen, mobile forms of phosphorus and potassium, increase of soil hydrolytic acidity. At the same time, the reaction rates of the soil salt solution in the neutral direction improve and the amount of absorbed bases increases. A similar dependence is observed when comparing the agrochemical parameters of weakly and medium-washed chernozem podzolic hard loam. In particular, a decrease in the content of humus, easily hydrolyzed nitrogen, a decrease in the magnitude of the reaction of the soil pH solution and an increase in hydrolytic acidity, which are negative factors. The largest negative manifestation was observed on the decrease in the value of hydrolytic acidity of the medium-washed soil - by 14.3%, and the least - on the value of the reaction of the soil pH solution - by 1.7%. At the same time, the increase in the degree of soil erosion from slightly washed to medium washed led to an increase in the medium washed chernozem podzolic heavy loam content of mobile forms of phosphorus and especially potassium, the content of which increased by 42.9%. Comparison of the change in the agrochemical condition of chernozem podzolic heavy loam slightly washed with medium washed showed that the humus content decreases more intensively in slightly washed soil, compared with the average washed, by 4.1%; the content of easily hydrolyzed nitrogen decreased more intensively in medium-washed soil, compared with slightly washed, by 1%. Hydrolytic acidity has increased by 6.4% more intensively on moderately washed soils compared to poorly washed soils.