The role and dynamics of infiltration in the moisture exchange structure of the aeration zone of an irrigated field

Abstract

Purpose: scientific and technical substantiation of the water balance components of an irrigated field in the particular case of connecting an aquifer and an aeration zone through a capillary fringe. Materials and methods. The research was carried out at Pobeda LLC, Bagaevsky district, Elkin farmstead, in 2018 and 2019. When organizing the research, an integrated approach was used: stationary and experimental sites were used. The climatic conditions of the research objects correspond to the semi-arid steppe zone, the soils are southern chernozems. Results. As a result of processing data from field experience, it was determined that with infiltration varying from 0.183 to 1.915 mm: the average daily water supply ranged from 0.8 to 7.33 mm/day; relative moisture reserves – from 0.61 to 1.20; average daily air temperature – from 8.0 to 23.0 °C; average daily air humidity deficit – from 2.1 to 12.0 mbar; average daily evaporation – from 1.3 to 7.34 mm/day. The correlation analysis determined that, according to the correlation coefficient, the infiltration value has the greatest correlation – 0.86 and 0.63 with water supply (M + P) and relative moisture reserves (W0), respectively; the smallest – 0.28; 0.38 and 0.37 with temperature (t), air humidity deficit (dφ) and evaporation (Eω), respectively. In turn, the multifactor correlation analysis determined that the formation of the infiltration runoff volume in the system of vertical moisture exchange of an irrigated field has the greatest connection with a paired change in the values of water supply and relative moisture reserves. Conclusions: infiltration of irrigation water and atmospheric precipitation beyond the root layer is determined by the obtained empirical dependence, is observed when the moisture reserves of this layer exceed the moisture reserves corresponding to the minimum moisture capacity and water supply, and has the greatest close relationship according to the coefficient of multiple determination (R²) 81 % (multiple correlation coefficient R = 0.899) with changes in these two factors.

Keywords

• aeration zone
• irrigated field
• water balance
• infiltration
• evaporation
• correlation analysis
• southern russia