Evaluation of the different soil management effects on salinity control in maize cropping by HYDRUS-2D

Continuous irrigation causes soil salinity and decreases soil fertility. The purpose of this study is to fi nd methods that can prevent soil salinity. Thus, a soil column with 15 cm stack height, under maize cultivation and tape irrigation has been simulated by HYDRUS–2D. In order to assess the effects of different scenarios including tape location (stack/ditch), stack height (in drip and surface irrigation), using mulch and irrigation water salinity on salinity accumulation in root zone in different time frames. The results show placing tapes on ditch will increase soil primarily salinity (0.65 dS m –1 ) 8%, 8% and 10% lower than placing it on the stack after 1, 5 and 10 years. Also, height stack is not very effective for controlling salinity in both drip and surface irrigation. Because, assessing soil columns with 0, 10, 15 and 20 cm stack height showed neglectable difference between salinity both in short term and long–term scenarios (according to variance analysis test). Using mulch is an effective way to control salinity because it can decrease evaporation. After 1, 5 and 10 years of irrigation in mulch presence, salinity increased 34.5%, 42.8% and 50% lower than without mulch scenario. Also, irrigating soil by water of different salinities including 0.7, 1.7 and 2.7 dS m –1 showed 77.5%, 83.5% and 84.2% increase in salinity after 10 years ago.