Role of calcium in optimization of fertility parameters and conditions of pedobiont existence in chernozems podzolized

Abstract

Physical, physical-chemical and biological properties of soil, and above all, the reaction of its medium, proportionaly dependent on its absorption capacity, especially in relation to such important macronutrient as calcium. On chernozem soils of Forest-Steppe zone during podsolization, saturation of soil by calcium decreases that causes increasing its acidity, it has detrimental effect on biota, especially for members of soil invertebrates, which in turn play an important role in the transformation of matter and energy of ecosystems in maintaining ecological functions and improving natural soil fertility. Therefore, the issue of calcium availability and ways to improve its content in soil is very popular. Primary importance becomes liming, which is not only a factor in increasing the pH of acidic soils, but also contributes to ensuring this element for soils, plants, and by food chain for animals and people. Purpose of the work – to establish the relationship between changes in physical and chemical parameters and the number of soil invertebrates (mesofauna) and structural-aggregate state of chernozem podzolized heavy loam by application of calcium ameliorants. Research on the effect of containing calcium ameliorants for physical and chemical and biological parameters of chernozem podzolized heavy loam were conducted during 2012–2014 in the Experimental Field «Slobozhanske» State Enterprise of National Scientific Center «Institute for Soil Science and Agrochemistry Research named after O.N. Sokolovsky» (Kharkiv district, Kharkiv region) small plot experiment. Scheme experiment: 1) control (without meliorants); 2) slaked lime; 3) dolomite; 4) cement dust; 5) red mud. It was determined the dynamics of changes in pH, Ca activity, number of lumbricids and structural condition of the soil. Measurement of pH and activity of calcium ions (Ca2+) was performed at the beginning and end of the growing season for three years in undisturbed soil (in situ) by direct potentiometry using ionselektyvnyh electrodes for certified methodology NSC ISSAR (MVI 31-497058-023-2005). Calculation of soil invertebrates (mesofauna) was performed by hand excavation and demolition soil samples by the method Gilyarova. The structural composition of soil was determined by screening in air-dry and wet sieving method N. I Savinova at a depth of 0–20 cm with subsequent determination coefficient structuring and vodotryvkosti. As a result of the application of calcium ameliorants on chernozem podzolized heavy loam, there was a significant increase in activity of calcium, which in turn led to the neutralization of soil acidity. These changes in physical and chemical properties of the soil were naturally reflected in the number of soil biota. Because, ground mesofauna is one of the most important indicators of the environment. For example, reducing biodiversity pedofauny weakens the zoo of processes, and as a consequence of land degradation. In the result of research, carried out during three years a positive linear relationship between increasing pH and number of lumbricids (rain worms) was determined, it was possible to note that by liming of chernozem podzolized the most favorable environmental conditions for life were created. At the same time it was proved that liming contributes to the formation of soil aggregates coagulation of colloids, and as a result soil structure improving. Statistical analysis of the data indicates a high level of correlation between the activity of calcium and structuring factor r=0,93. At the same time, there is a pattern to increase structuring coefficient by increasing the number of lumbricids (r = 0,74). Such dependence confirms the key role of calcium in the course of soil processes, and the need for a systematic approach in the study of influence of external factors on soil. In this article it is proved that the application of calcium ameliorants on chernozem podzolized, not only neutralizes soil acidity, but also improves conditions for the existence of soil invertebrates, which make a kind of biological soil reclamation, that ultimately contributes to its fertility reproduction and self-regulation.