Peculiarities of formation of structural-aggregate composition of soil in cultivation of maize by systems of organic agriculture in the Danube Steppe of Ukraine

Abstract

The growing demand for maize at the world marketof agricultural products has prompted Ukrainian farmersto significantly increase its production. Occupying oneof the leading places among grain crops in the grain balanceof the Danube Steppe of Ukraine, maize is not always ableto achieve its biological potential and high-yielding potential.This issue becomes especially relevant in the possibilityof obtaining high yields of ecologically clean maizegrain in terms of organic farming in the southern regionsof Ukraine.Deterioration of fertility of chernozem (black soil)s and their water-physical and agrophysical propertiesas a result of intensification of agriculture and significantchanges in climatic factors with increasing air temperatureand declining moisture has prompted to investigatethe formation of structural and aggregate soil compositionwith the introduction of various basic systems pre-sowingcultivation and maize crops care system, against the backgroundof the use of biodestructors for the conditionsof the Danube Steppe of Ukraine.The study was conducted in a fixed three-factor experimentwith ordinary chernozem (black soil). Studies haveshown that the methods and depth of basic tillage, the useof biodestructors to improve the decomposition of by-productsof the predecessor, as well as an improved systemof pre-sowing tillage and maize care in the experiment, insome way influenced the formation of structural and aggregatesoil composition.The positive effect of the use of biodestructors Ecostern1.5 l/ha and Cellulad 2.0 l/ha in the creation of structuralaggregates and the increase in the content of agronomicallyvaluable fraction of 0.25–10 mm has been established.Thus, looking at the option with plowing the application of the biodestructor Ecostern 1,5 l/ha contributed tothe increase in the structural composition of the soil fractionof 0.25 mm by 1.13%, and in the variant with the applicationof Cellulad 2.0 l / ha, respectively by 2.09%. Minimizationof the main cultivation for maize in organic agriculture bycarrying out flat-cut shelfless tillage by 14–16 cm, or diskingby 10–12 cm, did not give the expected positive resultsand still much smaller than shelf plowing. The applicationof the improved system of pre-sowing tillage provideda slight improvement of the structural and aggregate compositionof the soil in the experiment due to the reductionof the content of fractions larger than 10 mm and less than0.25 mm.The highest coefficient of soil structure was obtainedin the experiment for turning the chips and wrapping postharvestresidues and by-products of the predecessor withthe introduction of biodestructor Cellulad 2.0 l/ha on the backgroundof improved system of pre-sowing tillage and maizeplants care and was 4.97 for the soil layer 10–20cm.