Agrogenic changes in the properties of dark chestnut virgin and arable soil with different use and irrigation

In the article, it was provided a comparative analysis of the ecosystem significance of soil characteristics transformed as a result of changes in the use conditions. At the three monitoring stationary sites in the Chaplinka district of the Kherson region, we studied the properties of dark chestnut soil (Haplic Kastanozem) on virgin lands (a biosphere reserve "Askania-Nova") and with more than a hundred years of use in agricultural production without irrigation and with a 50-year irrigation with water from the Kakhovsky trunk canal. Changes in the salt regime of the soil and the composition of exchangeable cations were established. In irrigation the total content of water-soluble salts up to 0.14-0.21% (toxic salts ‒ up to 0.06-0.15 %) was increased. The composition of salts was changed, their migration and accumulation in the lower soil layers. Under the influence of fresh water irrigation the process of dealkalinization in the dark chestnut soil took place. The involvement of virgin soil in agricultural use led to a decrease in the total content of humus and the transformation of its group composition. The content of humic acids (HA) was decreased. The content of fulvic acids (FA) was increased. The HA/FA ratio in the 0-10 cm layer changed from 2.6 (in virgin soil) to 1.6 in irrigated soil. The plowing and agricultural use of the dark chestnut soil led to a change in the state of the microbial cenosis. The number of microorganisms assimilating mineral and organic nitrogen, actinomycetes, oligotrophs, and eutrophs were increased. With irrigation the degree of transformation of the microbial cenosis increases. The indicator of biological degradation of irrigated dark chestnut soil was 4 %. This corresponds to a low level of degradation. A set of 10 indicators of the quality of the studied soil was proposed for calculating the level of its provision of ecosystem services (supplying and supporting). The algorithm and calculation results are presented. The soil of all monitoring sites of Markeev station is characterized by a high level of provision of ecosystem services. In virgin soil it was 8.3 points; in arable soil without irrigation it was 7.2, and with irrigation it was 7.5 points.

Patterns of soil processes on dark chestnut soil under conditions of its use in the conditions of the steppe of Ukraine

As a result of four-year research, the patterns of soil processes development depending on the parameters of reclamation load were established. It was established that at the end of vegetation season irrigation of crops with water with high mineralization leads to deterioration of soil structure, where the largest amount of aggregates >10 mm (42.67%) was observed during disk tillage (a similar trend was observed for aggregates <0.25 mm). On average, during 2016-2019, under the influence of irrigation, the transformation of the ionic composition of the aqueous extract led to a change in the chemistry of salinity from sodium chloride-sulfate to calcium-sodium sulfate in all variants, regardless of the studied factors. The most favorable conditions for the formation of the yield in the experiment were created under a differentiated system of tillage with one split for crop rotation and with the introduction of increased doses of fertilizers, which per 1 ha of crop rotation area provided the highest productivity, which was for corn 15.49 t/ha, sorghum - 8.72 t/ha, wheat winter - 7.07 t/ha, and only for soybeans the best conditions this year were created for 1 option - 4.27 t/ha. The highest level of profitability from 1 ha of crop rotation area was obtained for the average fertilization background 2 (N120P52,5 ) for differentiated tillage - 199%, while for other tillage systems and fertilizer doses it decreased to 33-189%.

Sorption of heavy metals by humic acids of chestnut soils

The purpose of this article is to study the sorption of heavy metals by humic acids of light and dark chestnut soil. The objects of research are the samples of dark and light chestnut soils, selected from an ecologically clean area of East Kazakhstan. Humic acids (HA) were separated from the soil at different pH values. At the same time the yield of HA was 0.075% from dark chestnut soil at pH 1.0, and it was 0.017% from light chestnut at pH=7.0. Further, the dependence of the sorption degree on the medium acidity was established. It was found that zinc and cadmium are better sorbed in a strongly acidic medium (рН1.0; 84.14%), while lead is preferably sorbed at pH 6.0, and the degree of its sorption is higher (93.54%). It was established that metals have a mutual effect, suppressing or enhancing the sorption of each other in bi- and polyelement variants. It was shown that cadmium significantly suppresses lead sorption in neutral media. Zinc more often increases the sorption of both cadmium and lead by 3 times. It was concluded that the binding of heavy metal ions by the organic fraction of the soil occurs due to the complexation with humic acids.

Emission of Carbon Dioxide from the Dark Chestnut Soil in West Kazakhstan

The necessity of studying and assessing emissions of carbon dioxide from the agricultural soils is related to the important role played by the soil in their formation. Active release of carbon dioxide shows changes in the content of the organic matter in the soil and its biological activity. Carbon dioxide emissions can be influenced both by biotic and anthropogenic factors. Due to the negative effect of grazing and arable plots on the soil respiration, unequal emission of carbon dioxide is noted. The research was aimed at assessing the dynamics of carbon dioxide emissions from the dark-chestnut soil, depending on the nature of the soil use in agriculture. The studies for determining the carbon dioxide flow rate were performed according to the standard variant of the closed dynamic chamber method. The results of studying the content and emission of carbon dioxide from the dark-chestnut soil of the agricultural lands in Western Kazakhstan are shown. The content and reserves of humus in the 100 cm layer of the studied soils are low, and the soil is characterized by low humus content. The total annual flow of carbon dioxide from the virgin lands is higher than that from the arable lands but is less than that from the pastures

Composition, properties and specificity of the impact of bird droppings on the fertility of dark chestnut soil

The article presents analytical materials of studying the chemical composition and properties of bird droppings in the Pokrovskaya PTF LLC of the Engels District of the Saratov Region. Its various types: dry, litter, dense consistency, semi-liquid, liquid, drains are analyzed. The loss of chemical elements at perfect and impaired storage technology and ways to prevent them are identified. The most promising of them is thermal drying. The specificity of the impact of high doses of bird droppings on the fertility of the fields adjacent to the poultry complex was revealed. Its effect on the reaction of the soil solution, the humus content, mobile forms of nitrogen, phosphorus, potassium, sulfur and trace elements is shown.