Сезонна динаміка щільності складення чорнозему опідзоленого західного Лісостепу України за різного використання в агроценозах

Abstract

Soil as multicomponent organized and complex ecosystem has a number of important ecosystem functions. Fertility is the most integrated of it, which is directly connected with all the functions and properties of the soil and is the result of effective cooperation. Thus, essential for optimal functioning of soil fertility is implementing its agrophysical properties that are the basis of the formation of high and stable crops yields. A special place to optimize the agrophysical properties takes soil structure density, which is the most objective and comprehensive summary measure. This statement came through the work of Y. B. Revuta, and his followers. These works had significant impact on the soil science development; thru bulk density peoples began to assess soil physical condition and its changes due to human impact. Soil compaction is the main reason of it productivity reducing. Plants feel strong anoxia when soil density index falls below 15%. Over compaction reduces soil biological activity, including nitrification, total number of cellulose destructors and actinomycetes. Soil density increase in 0.1 g/cm3 compared to an optimum – course crops yield reduction by 15-20%, and 0.2 g / cm3 - 50%. Soil structural condition, bulk density, water-physical properties, crop productivity are largely dependent on its tillage type, nutrient management in crop rotation. Tillage (especially deep plowing) and fertilization significantly change the natural structure of black soil. Thus, the result of years of plowing at the same depth a dense plow sole is formed. It affects many soil processes, especially in water, temperature and soil gas regime. V. D. Mukhas’ found that one of the main signs of land degradation indicators are bad soil structure and density structure of the soil during the growing season. Vladimir Medvedev says’ that mechanical tillage and soil structural changes caused by it are the main reason of water-physical properties degradation in arable land. Fedorovskyi D.V. notes’ that high soil density make soil water and nutrients unavailable for plants. Wheat roots do not penetrate into the layers of soil with a density of 1.65, roots of vegetables - 1.45 g / cm3. Apple trees are not durable if there is compaction layer under 1.55 in 2 meter layer of medium loamy soil, and more than 1.30 g/cm3 on clay soils. Kopytko P.G. indicates that density of soil with loamy texture (20-80 cm layer) in root zone under highly productive apple orchards is around 1.2-1.3 g/cm3. Therefore, these figures can be considered as an optimal for the functioning of the root system and fruit crops nutrition. In particular, it is known that manure as an organic improves soil physical, chemical, agrophysical properties and humus regime. Nowadays manure becomes irrelevant from economic point of view. Therefore against the backdrop of rising rates agrotehnogenesys in the literature there are more and more reports of adverse changes in the properties of soils under the influence of mineral fertilizers. Thus, G.V. Dobrovolsky indicates that fertilizer even in small doses lead to dispersion structure, reduced agrigates strength, reducing the visible poroznosti and increase bryluvatosti (Dobrovolski, 1983). That is why additional study of the effect of different soil tillage and nutrition plans on podzolic chernozem bulk density in different soil-climatic and farm specific conditions is needed.