Investigating the Effect of Irrigation Interval in Subsurface Drip Irrigation System on Soil Salinity Changes and Corn Plant Yield for the Central Regions of Khuzestan

To monitor and compare the changes of salts in the soil profile around the roots of the corn plant, the plant yield, and the productivity of corn water, an Experimental was conducted in a completely randomized block of three repetitions in two crop years 2017-2018 and 2018-2019 at Ahvaz Agricultural Research Station. Experimental treatments included two subsurface drip irrigation systems with a working depth of 30 cm from the soil surface and tape irrigation and two irrigation intervals of 2 and 4 days. The results of monitoring soil solutes obtained from sampling depths (0-25, 25-50, and 75-50 cm) showed that soil salinity in the second year in both systems as a result of improving the quality of irrigation water from 3.61 dS/m to 2.01 dS/m, it was reduced by two times. The results of soil salinity monitoring showed the highest ratio of salinity reduction with a 2-day irrigation interval in both irrigation systems. The most leaching was done at the irrigation depth of 25-50 cm in the subsurface drip irrigation system and at the depth of 0-25 cm in the tape system. The highest yield of corn dry fodder was 9.13 and 7.13 tons per hectare, respectively, and the best water efficiency based on dry corn fodder at the rate of 13.74 kg/m was obtained in the strip drip irrigation system (tape) with a two-day irrigation interval and in the second crop year. Also, the results of the soil salinity measurement showed that the implementation and exploitation of the drip irrigation system can be the basis for improving the quality of the soil as the most important non-renewable resource of agriculture.