Dynamics of productive moisture in the soil for the cultivation of winter wheat in the crop rotations of the Left-Bank Forest-Steppe of Ukraine

Abstract

The results of the researches were obtained during 1999–2015, on the typical low-humus heavy-loamy black soil of the Left-Bank Forest-Steppe of Ukraine show that during the spring-summer period of vegetation there is a predominance of moisture losses over its accumulation in the soil. However, in this period prevailing productive costs, that is, soil moisture is more spent on the formation of crop and partly on the physical evaporation from the surface of the soil. The largest reserves of productive moisture in the ground under winter wheat were observed in spring at the time of the restoration of its vegetation. Through the winter and early spring precipitation of moisture in 100 cm soil layer was 181.8 mm, 43.8 mm or 37.1 % more than the average long-term rate. It was determined the fact that in most winter wheat is consumed from the soil moisture autumn-winter inventories during the period of vegetation culture to exit the tube – 43.4 mm. In this case, the total expenditures of moisture from the soil and precipitation are 70.7 mm or 27.8 % of the total expenditures of moisture by culture during the growing season.

In the future, from the outlet to the tube to beginning to ear the general flow of moisture decreases, and from the ear to the onset of the waxy maturity of the grain, on the contrary, increase. So in the field of winter wheat they were, respectively, 66.8 and 116.6 mm, that is, the difference, compared with the period from the restoration of vegetation to the output of the tube was 3.9 and 46.1 mm. However, studies show that plants of winter wheat  the most intensively used wet during the growing season from the restoration of it in spring to the ear eruption. This period of growth and development of winter wheat plants is most sensitive to the deficit of moisture in the soil, and its reserves determine the upper limit of productivity of crops.