Combined Effects of Water Quality and Slope Gradient on Infiltration Under Simulated Furrow Irrigation for a Soil in North China

摘要

Furrow irrigation is the main irrigation method in the world, including the developed and developing countries. Its management is important for the improvement of water utilization efficiency. The effects of irrigation water quality and furrow bed slope on infiltration were studied with simulated furrow irrigation experiments in laboratory. The experimental treatments were salt concentration (5, 10, 20, and 30 mmolc L-1), sodium adsorption ratio (SAR) (0.5, 5, and 10 (mmolc L-1)0.5), and slope gradient (1%, 3%, and 5%). Runoff amounts during experimental processes were measured to estimate infiltration amounts under the given inflow rate. The experimental results indicated that soil infiltration rate as a temporal function can be reasonably well represented with Kostiakov equation for various combined conditions of salt concentrations, SAR values, and slope gradients. Total infiltration amount generally increased with salt concentration but decreased with SAR level in irrigation water. It also decreased with the increased slope gradient of irrigation furrow. Different combinations of salt concentration and SAR had different influences on infiltration process. The effects of irrigation water quality on infiltration were promoted with increase in slope gradient. The effects of irrigation water quality and slope gradient on infiltration should be considered together to further improve water utilization efficiency in furrow irrigation practice.