Spatial-Temporal Distribution of Soil Salt Crusts under Saline Drip Irrigation in an Artificial Desert Highway Shelterbelt

Understanding the formation and spatial-temporal distribution of soil salt crusts (SSCs) is important for the sustainable management of the artificial shelterbelt and high-salinity groundwater utility in the Taklimakan Desert in Northwest China. The SSCs in this area were sampled, and their thickness and electrical conductivity (EC) were analyzed to examine the formation mechanism and the spatial-temporal patterns of the SSCs in the shelterbelt, which is drip irrigated with high-salinity groundwater in the Taklimakan Desert. Results demonstrated the following: (1) Soil-moisture depletion and salt accumulation at the soil surface occurred simultaneously. The soil water and salt in the different areas around the drip irrigation emitter showed different temporal dynamics in an irrigation cycle; (2) SSCs EC increased at a logarithmic rate, and SSCs thickness increased linearly with irrigation water salinity; (3) SSCs showed evident spatial distribution around the drip irrigation emitter. The EC initially increased with increasing distance from the emitter but subsequently decreased in different directions around the emitter. The highest EC was recorded at 40 cm from the emitter; (4) Topography had a significant effect on the spatial distribution of SSCs. The EC at the upslope of the emitter was higher than that at the downslope; (5) SSCs thickness showed an initial rapid increase with shelterbelt age, which was followed by a gradual increase. However, EC decreased with shelterbelt age. Our findings can contribute to the shelterbelt design, construction, utility, and sustainable management and the soil and water conservation in shifting desert regions.