What Is Salt-leaching Effect of Drip Irrigation in Elaeagnus Angustifolia Shelterbelt Extremely Arid Area

Elaeagnus angustifolia plays a very important role in maintaining ecosystem function in the extremely arid areas of Xinjiang, China, because of its tolerance to severe drought, high salinity and alkalinity in soils. However, few reports on impact of leaching salt of drip irrigation in E. angustifolia shelterbelt were found.

In order to understand the leaching-salt effect of drip irrigation on soil in shelterbelt, ZHAO Xinfeng et al. compared soil salinity level in shelterbelts under different emitter distance and different planting years using 3 years of monitoring data from a typical oasis located in an extremely arid area in northwest China. The variation trend of salinity level during the whole growing season and in nonirrigation season was analyzed.

The results indicate that under narrow emitter distance (1.5 m), the soil layer with the highest salinity level was located deepest (50–85 cm). Under wide emitter distance (3 m), the soil layer with the highest salinity level was located shallower (45–80 cm). Drip irrigation effectively decreased the soil salinity level. With the increased in irrigating years, the salt-leaching effect was better. Most of the soil salts were brought downward to the soil layer below 30, 50 and 70 cm, respectively, in shelterbelts that have been irrigated for 1 year, 2 years and 3 years. Soil salinity level presented an increasing trend during the growing season. The largest change of soil salinity level fore-and-aft the irrigation was found in 20-cm depth, followed by the 40-cm depth and then the 60-cm depth. In nonirrigation season, salt was accumulating at the surface in shelterbelts. Among all the shelterbelts with different forest age, the salinity level on the surface was the highest in the 2-year-old shelterbelt.

The results improve references for the study of the soil salt dynamics under drip irrigation. The study was published in Water and Environment Journal in June 2014.