V. Gr. Zhukov, V.M. Chesnokov, N. D. Lukin
All-Russian Research Institute of Starch and Processing of Starch-Containing Raw Materials – a branch of the Federal Research Center for Potatoes named after A.G. Lorkha, ul. Nekrasova, 11, d.p. Kraskovo, g.o. Lyubertsy, Moskovskaya obl., 140051, Russian Federation
Abstract. Successful crop production is facilitated by the possibility of calculating the distribution of soil moisture along the height of the capillary-moisture zone, taking into account the distance to the soil surface and the root system of plants. The research aimed to derive analytically a formula for calculating the moisture content of the soil and its change along the height of the capillary fringe that occurs on the aquifer. The solution was based on the ratio of the total area of pores occupied by capillary water to the entire area of pores in the same section, the probability density function of the pore areas distribution, the integral function of their distribution, and the Jurin formula. The calculation formula for soil moisture content along the height of the capillary fringe was obtained. The graphs of the calculation example confirmed the possibility of having two layers of the capillary fringe: a saturated bottom layer with continuous filling of pores with water and an unsaturated surface layer. An intensive change in the moisture content of the pore space occurred only along a relatively small initial section of the capillary fringe height from the total height determined by the Jurin formula. The calculated numerical value of this layer of 1.4 m corresponded to the known results of field experiments, according to which the value of this indicator is mainly within 2 m. In this regard, it can also serve as a limitation on the minimum pore size taken into account in the Jurin formula. For the conditions of the considered example, the pore size turned out to be 15.1 μm. The calculation formula made it possible to determine the condition for the location of a capillary-moisture zone with high water content in the root zone of agricultural crops for an exact soil. The formed analytical approach is applicable to similar problems for porous media of various origins and types of probability density functions of the distribution of pores by size and area, and in this it is universal.
Keywords: soil; moisture content; capillary-moisture zone; probability density function; Jurin formula.
Author Details: V. Gr. Zhukov, D. Sc. (Eng.), chief research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); V.M. Chesnokov, Cand. Sc. (Eng.), senior research fellow; N. D. Lukin, D. Sc. (Eng.), deputy director.
For citation: Zhukov VGr, Chesnokov VM, Lukin ND. [Calculation of soil filling with capillary fringe water along its height]. Dostizheniya nauki i tekhniki APK. 2022;36(3):85-90. Russian. doi: 10.53859/02352451_2022_36_3_85.