Почвоведение и агрохимия
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Почвоведение и агрохимия, №4, 2020 16 Toxic salts -by calculation accord- ing to the methodological recommenda- tions of N. Bazilevich and N. Pankova [1]. Accounting for the alfalfa harvest was carried out on a key site (in three rep- lications) of 4´4 meters in size with the drying of the green mass to an air-dry state. The field, stationary and laboratory- analytical methods were used for research. RESULTS AND DISCUSSION Observations of soil formation pro- cesses showed that prior to reclamation activities (1985), the initial humus content in the 0-20 cm layer was ~ 2.5 %. After ma- jor washing of saline soil (1985-1986) and subsequent 3-year cultivation of alfalfa (1986-1989), there was a slight increase in the amount of humus in most experiment points (which was 2.88%). As a result of a long post-melioration period (2016), the humus state of the stud- ied soils shows little signs of improvement. So in the composition of humus there was a change in the soluble part of humus, and the ratio of groups of humic and fulvic ac- ids can be stated about some improvement in the composition of humus - it is equal to one. The humus content increased from 2.88 % to 3.08 % (0-20 cm), organic car- bon increased from 1.19 % to 1.98 %, and the ratio of humic acid to fulvic acids in the 0-40 cm layer increased from 1.0-1.03 to 1.04-1.18. Comparative assessment of changes in the relative content of humus in the soils of the agricultural landscape be- fore reclamation and after reclamation was carried out using the "soil index" method (Aidarov I. P., 2004, 2009) [9].The basis of the definition, which is based on the defini- tion of humus reserves and composition (humic and fulvate), reserves of the main elements of mineral nutrition (nitrogen, phosphorus, potassium) and acid-base in- dicators (pH and hydrolytic acidity), ac- cording to the formula: where S is an integral indicator for assessing the level of soil fertility, points; G gn , G fk andfulvate humus reserves, % or t / ha; N, P, K - the presence of food ele- ments (nitrogen, phosphorus, potassium), as a percentage of their maximum content in the soil; φ-coefficient that characterizes the efficiency of fertilizers depending on the pH; N g -hydrolytic acidity, mg-EQ/100 g of soil; p-coefficient, ha / t; β-coefficient, mg-EQ/100 g of soil. The calculations are presented in the following table №1. Тable № 1 - Assessment of changes in soil fertility Indica- tors Humus content,% Elements of mineral nutrition Hydro- lyte acid, mg- EQ/100 Coefficients The level of soil fertility, S G гн G фк G N P K Н г ρ, ha/t β, mg- EQ/ 100 ϕ mark % Before reclama- tion, (original- 1985) 0,10 0,10 2,50 1,50 0,35 1,46 1,5 6,4 4 0,3 5,15 0,0 |