Impact of irrigation and soil compaction on agricultural lands with shallow ground water table

Abstract

Salt accumulation in agricultural soils is a long-lived problem for farmers in many regions of the world, leading to a decrease in crop yields and threatening food security. The salinity challenge amplifies in absence of proper soil water drainage in areas with shallow groundwater table. Hence, this study was carried out by examining the impact of irrigation pattern and soil compaction on the salt dynamics within a soil profile with a shallow aquifer. A series of laboratory-scale column experiments were conducted to examine the impact of different irrigation patterns, water quality and soil compaction conditions on salt dynamics. Two water qualities were applied: fresh (DI water) and saline (~3.4 mS/cm). The soil columns (60 cm height and 16 cm diameter) were packed with agricultural soil from a 10-year non-tilled profile of an apple farm located in the Konya plain, Turkey. A saline shallow water table was maintained at the bottom of the columns. The experiments were numerically modelled with the HYDRUS-1D computer program which can simulate water and solute movement in unsaturated soils. Results showed that without having proper drainage the salinity within the profile would only accumulate in the presence of a shallow saline aquifer. Furthermore, the numerical simulations showed that short-term solutions such as the application of freshwater during the critical plant growth period can limit the accumulation of salts in agricultural soils. The type of soil, the kind of plant and the availability of freshwater all play a role in the practicability of such short-term solution.