Мелиорация и гидротехника (Aug 2023)
ON TRANSFORMATION OF DRIP SOIL MOISTURE CONTOUR IN AFTER-IRRIGATION PERIOD
Abstract
Purpose: to determine special features of changes in the geometric and moisture parameters of the soil drip moisture contours after irrigation. Materials and methods. The basis for generalizations on the dynamics of moisture contours transformation was the results of field studies conducted on three experimental plots, the top soil of which is represented by medium-thick southern chernozem, characterized by the content of physical clay Wг equal to 45.0; 52.5 and 70.2 % by dry soil weight. Measurements of contour parameters were carried out in 0, 12, 24, 36, 48, 72 and 96 hours after completion of drip irrigation during post-irrigation period. Results and discussion. An analysis of the shape and geometric dimensions of the contours and internal contour isopleths, recorded in post-irrigation periods of different duration, made it possible to determine the qualitative features of their change over time. An increase of the linear, areal and volumetric dimensions of moisture contours over a certain time period, stabilization and their subsequent decrease, up to the complete contour drawdown, has been defined. Of all the variety of factors influencing the process of contour transformation, soil conditions determined by soil granulometry are considered as the main ones. An empirical dependence that describes the functional relationship between the linear parameters of the contours, the content of physical clay in the moistened soil profile, and the duration of the post-irrigation period has been obtained. Conclusions. Based on the field study data, the qualitative-quantitative parameters of transformation of the drip soil moisture contours in the post-irrigation period, typical for southern chernozems of medium-thick light clay, medium and heavy loam, were determined. The predicted parameters of drip soil moisture contours were compared with the known data, allowing to make a conclusion about their acceptability for practical application in the development of drip irrigation regimes for agricultural lands.
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