Scientific Journal of KubSAU

In the soils of rice fields, eluvial gley processes develop, which are manifested in redistribution of silty particles along the profile, water-soluble humus, mobile compounds of iron and phosphorus. Most intensively, these processes are developed in meadowbog soils, confined to closed depressions of the plains plain. Meadow-black soils lying on elevated relief elements have more favorable physical, physicochemical and oxidation-reduction properties for cultivating rice and accompanying crops in crop rotation. The highest yield of rice is formed on high checks and higher at 12,4 c/ha than on low ones

Acidic properties of the mineral matrix of meadow chernozem and meadow-boggy soils of Krasnodar region are characterized by a total adsorption capacity of ammonia in the range of 32-61 µmol / g. The lowest acidity of the matrix was observed under conditions of permanent rice cultivation for 80 years (32- 33 µmol NH3/g). The mineral matrix of rice soils depends on the meliorative state and the granulometric composition of these soils. At low fields of meadowboggy soils, heavier in granulometric composition, the total acidity of the mineral matrix is 51- 53 µmol NH3/g on high checks of lighter meadow chernozem soils – 34-45 µmol NH3/g. In the upper soil, with a less acidic matrix, the Fe3+ content increases and the amount of Fe2+ decreases. The reverse pattern is found in the lower soil with more pronounced acidic properties of the matrix. A proportional relationship between the humus content and the acidic properties of the mineral matrix is found. The highest yield of rice is formed on meadow chernozem soils with a less acidic mineral matrix

In the soils of rice fields, eluvial gley processes develop, which are manifested in redistribution of silty particles along the profile, water-soluble humus, mobile compounds of iron and phosphorus. Most intensively, these processes are developed in meadowbog soils, confined to closed depressions of the plains plain. Meadow-black soils lying on elevated relief elements have more favorable physical, physicochemical and oxidation-reduction properties for cultivating rice and accompanying crops in crop rotation. The highest yield of rice is formed on high checks and higher at 12,4 c/ha than on low ones

In the soils of rice fields, eluvial gley processes develop, which are manifested in redistribution of silty particles along the profile, water-soluble humus, mobile compounds of iron and phosphorus. Most intensively, these processes are developed in meadowbog soils, confined to closed depressions of the plains plain. Meadow-black soils lying on elevated relief elements have more favorable physical, physicochemical and oxidation-reduction properties for cultivating rice and accompanying crops in crop rotation. The highest yield of rice is formed on high checks and higher at 12,4 c/ha than on low ones

The content of selenium in the soils of various genetic types varies widely. Its amount is lower in soils formed on volcanic rocks. On average, it is 0.2-0.6 mg/kg. In the soils formed on sedimentary rocks, the content of selenium is often in the range of 4.5-5.0 mg/kg and depending on the conditions of formation it varies widely, sometimes reaching 100 mg/kg. Predominantly they are alkaline soils, selenium concentrations in the soil solution is 10-6 moles. The content of selenium in most soil types of the Russian Federation and CIS countries varies in the range of 0.01-1.0 mg/kg. Floodplain, chestnut soils, black soils and gray soils are more enriched (0.3 to 1.0 mg/kg), whereas sod-podzolic and sandy soils are relatively depleted (0,05-0,2 mg/kg). Systematic application of mineral fertilizers on the fields of crop rotation leads to a decrease in total content in the leached black soil. Fertilizers contribute to increased mobility of this element and more intensive involvement of it in the biological cycle

Chromium in soils is represented by the following forms of connections: 1) stationary; 2) strongly bound in the composition of primary and partially secondary clay minerals, with one and a half aluminum and iron hydroxides; 3) exchange bound on the surface of one-and-a-half oxides and clay minerals; 4) associated with organic matter of soils; 5) water-soluble compounds. The gross chromium content (70.1-78.3 mg/kg) in leached chernozem is well below clark soils of the world (100 mg/kg). The share of mobile, acid-soluble and acid-insoluble forms of the element compounds is 0.01, respectively; 7.09 and 92.9 % of its gross content. After three rotations of 11-full grain-grass-tillage crop rotation without mineral fertilizers, the chromium content in leached chernozem has not undergone significant changes, even to some extent there is a tendency of its reduction. This indicates the absence of serious natural sources of chromium in the soil. Scientifically-based system of fertilizers for agricultural crops does not lead to anthropogenic pollution of leached chernozem with chromium. The removal of this element with crop yields is compensated by its receipt in the form of ballast with mineral fertilizers

The article discusses the change in the magnetic properties of soils of different agricultural use, depending on the conditions of soil formation. The objects of study are leached chernozem of Western Ciscaucasia, meadow chernozem and meadow bog soils of rice agrolandscapes. The results showed that with an increase in the degree of hydromorphism, the magnitude of the magnetic susceptibility of the soil decreases. The leached chernozem has the highest magnetization of the profile. In soils formed under the influence of hydromorphic soil formation, magnetic susceptibility is reduced by 3.0-3.5 times in rainfed conditions and deposits, and by 6.0-12.0 times in soils of rice agrocenoses

The article shows results of using a mineral fertilizer system on the conditions of the mineral nutrition of winter wheat grown on leached chernozem in 11-field grain-tilled crop rotation conditions of stationary experience. We have also shown the effect of various norms and types of fertilizers on grain yield. Grain increase as a result of using N40 and N40Р30К20 ranged from 0.54-0.50 t / ha, average and elevated rates increased the yield of winter wheat by 0.97 and 1.03 t / ha, which is higher than the control by 17.1 and 18 , 2%

The article studies current state of fertility and productivity of leached chernozem used in the 11-field grain-grass-row crop rotation. Under the conditions of a stationary field experiment, a soil section was laid, a morphological description of the soil was carried out, its magnetic susceptibility χ was measured, soil samples were selected from soil-genetic horizons, in which the particle size distribution, physical and chemical parameters were determined. Studies have shown that leached chernozem is characterized by an addition density of 1.30 g/cm3, a solid phase density of 2.67 g/cm3, a total porosity of 51.9 %, χ = 1,045 × 10-3 units SI, pHwat. 6.5 units, humus content 3.2 %, its stock in the layer A + B = 468.2 t/ha, the sum of the exchange Ca2+ and Mg2+ 42.8 mg.eq./100 g. The use of mineral fertilizers increases the productivity of leached chernozem: the yield of sunflower of 11-field grain-grass-row cultivated crop rotation exceeds the control without fertilizers by 1.02-1.62 t/ha