Enhancing soil drought induced by climate change and agricultural practices: Observational and experimental evidence from the semiarid area of northern China

Increased water scarcity has led to a decade-long soil drought in the semiarid area of northern China, which caused food insecurity in this region. However, there is a lack of sufficient observational evidence about how climate change and agricultural practices have interactively affected this soil drought. Long-term in situ soil moisture measurements collected in agricultural experimental plots indicate that the mean temperature and precipitation during the growing season have reduced soil moisture by 11.2%, and agricultural practices have aggravated the soil drying trend in the 0-100 mm soil layer over the past three decades. Our results also show that planting water-expensive crops (e.g., potato and maize) may aggravate soil drought. Crop rotation increases soil water consumption by 8.9-12.6% over continuous cropping. Excessive fertilizer use increases water consumption by 25.4-46.9% and decreases the water use efficiency (WUE) by 14.6-35.3%, while tillage accounts for the consumption of 10.3% more soil moisture than no-tillage. Our results indicate that agricultural practices, including crop rotation, a high fertilizer input, and tillage, may increase water consumption and aggravate soil drying. Our findings call for effective strategies for mitigating soil drought in semiarid regions, such as an adjustment of the cropping system, reduced fertilizer use, and improved conservation tillage.