Soil physical and chemical properties and drain water quality as affected by irrigation and leaching managements

Saline-sodic soils commonly display a poor soil structure which is associated with the reduction in soil quality. Therefore, optimal management of soil and water salinity in saline-sodic soils should be regarded as an important factor in sustainable agriculture. The main purpose of the current study was to address the combined effect of irrigation and leaching managements on soil physical and chemical properties and drain water quality. Treatments including three irrigation water qualities, ECi = 0.6, 3 and 6 dS/m, two irrigation managements and three irrigation durations (8, 45 and 100 days). Two irrigation managements included intermittent irrigation at the depletion of 30% field capacity (M-1) and daily irrigation with leaching fraction of 0.15 (M-2) both followed by heavy leaching. Heavy leaching tests were applied on soil columns after 16, 56 and 114 days. The results showed that irrigation management and duration of the irrigation were found to be much more effective on infiltration, while irrigation water quality had a minor effect. The results revealed that final infiltration capacity under the daily irrigation was higher than the intermittent irrigation. Daily irrigation could control the salt until the medium water quality (ECi = 3 dS/m) and its soil chemical properties were similar to the intermittent irrigation. Daily irrigation had the most effect on EC control of soil and consequently on EC reduction of cumulative drain water compared to the intermittent irrigation. Reduced salinity by heavy leaching under the daily irrigation was more than intermittent irrigation. Under the intermittent irrigation, heavy leaching has increased the soil sodium adsorption ratio compared to the daily irrigation. Overall, under the daily irrigation, the soil physical and chemical properties were more suitable than the intermittent irrigation. According to the results, the intermittent irrigation is recommended in the areas where there are water resource limitations.