Soil salinization after long-term mulched drip irrigation poses a potential risk to agricultural sustainability

Prevention of soil salinization is key to agriculture in arid and semiarid regions. Because of the desert climate and extensive demand for irrigation, mulched drip irrigation (MDI) has been practised across Xinjiang, the largest cotton-planting region in China, since the early 1990s, reaching 2 × 10 ⁶ ha in 2014. Although MDI can minimize irrigation-induced soil salinization, long-term practice of MDI causes salts to accumulate in the root zone and on the bare soil surface between mulches, which leads to unsustainable crop yields. Here, we summarize the mechanisms and factors that affect soil salinization under MDI management. A proper MDI scheme that meets the requirements for crop growth and the flushing of excessive salts is essential for agricultural sustainability in Xinjiang and other oasis agroecosystems around the world. Highlights: Long-term mulched drip irrigation causes salt accumulation in the subsoil and on the surface. A proper irrigation scheme that sustains crop growth and flushes excessive salts is crucial.