Spatial Heterogeneity of the Conditions for Micronutrient Plant Nutrition on Slope Soils

Abstract

The problem of fortification of micronutrient plant nutrition is of present interest due to the high level of pH and carbonates content in soil, which are closely connected with each other and have a determining influence on the adsorption and transformation of trace elements in soil. Similar effects of trace elements deficiency determined by the same reasons are often observed in most northern regions of Ukraine, Bulgaria and Russia. This is most typical of the “warm” slopes exposed to south, south-east and south-west where due to increased solar radiation in the absence of trees there are conditions for enhanced transpiration with dominant upward water flow in soil. Redistribution of heat and moisture from the landscape is an integral feature of the soil formation in slopes, leading to spatial differentiation of soil profile depth, intensity of humus accumulation, depth of boiling of carbonates, etc.
However researchers have not associated to the present the specifics of soil formation on slopes with the edaphic conditions of germination of crops located in different places on the slope.
The sloped soils on the left banks of the steppe in Ukraine are characterized by a high degree of spatial heterogeneity in the conditions of micronutrient nutrition of plants associated with abrupt differences in terms of pH, carbonates content, clay minerals and organic matter in the various parts of the slope.
As a result, in those parts of the slope where the water-soluble carbonates are elevated to the surface, it is detected deficiency of such physiologically needed elements as Zn, Mn, Fe, Co. The soil mineral composition and its clay part and mainly montmorillonite, mixed layer minerals and quartz have a great impact on the mobility and accumulation of trace elements in sloped soils.