Scientific Journal of KubSAU

The article shows a possibility of using neutralized phosphogypsum as multicomponent fertilizer for rice crops. In the system of rice fertilization replace of 150kg/ha of ammophos during main application with 40 kg/ha of carbamide and 4 tons/ha of phosphogypsum applied in spring provides the same content of available forms of nitrogen, phosphorus and potassium in soil and plants as with application of N120P80K60. Application of phosphogypsum in spring before sowing is less effective than application in autumn before plowing. When applicating phosphogypsum in spring 2013 with a rate of 4 t / ha the obtained yield was 0.57 t / ha or 8.98% higher than in the control, and in 2014 it was not different from that obtained with the application of solid mineral fertilizers with a rate of N120P80K60. With autumn application of phosphogypsum increase in yield in 2014 was 0.98 t / ha or 12.6%. Yield growth is the result of increasing the survival of plants, grain content in panicle and grain weight per plant. Use of neutralized phosphogypsum is economically feasible. Relative benefits of using phosphogypsum instead of phosphorus fertilizer (ammonium phosphate) on rice crops in the Federal State Unitary Enterprise SRSF "Krasnoarmeyskiy" named after A.I.Maystrenko, Krasnoarmeyskiy district of Krasnodar region at the optimal rate amounted to 13139.7 rubles per 1 ha

The contents of lead in soils are primarily determined by regional factors: the composition of parent rocks, relief, climate, vegetation. In recent years, these factors have increased the anthropogenic source of element. In order to assess its impact, requires knowledge of the natural, i.e., background lead levels, the so-called reference points, which can later be used to monitor changes occurring in the soil. Under background refers to the content of the element in soils at a great distance from the areas of receipt of contamination. Background content of lead in each type of soil depends mainly on composition of parent rocks. The correlation coefficient between the content of lead in parent rocks and soils, with the background contents is equal to 0,86±0,17 at p=0,95. For each soil type there are low variations in lead content due to the composition of parent rocks. Lead concentrations in the soils increased at the expense of its receipt from the atmosphere, irrigation water, drainage during mining, as a result of agricultural use, lead containing chemicals. Comparing the obtained results with existing currently permissible concentrations (APC, MPC) it is necessary to note that the lead content in leached chernozem soil after three rotations of the rotation may not cause any pathological changes or anomalies in the course of biological processes and lead to accumulation in the agricultural plants, and therefore may interfere with biological optimum

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