The difference in cultivated land soil quality: a comparison between the north and south sides of the Tianshan Mountains.

There are significant regional disparities between the northern and southern sides of the Tianshan Mountains, which the cultivated land soil quality shows different characteristics. In order to further understand the soil quality difference of the northern and southern sides of the Tianshan Mountains, we analyzed the influences of long-term drip irrigation (DI) in northern Xinjiang (NX) and drip irrigation during the growth season combined with flood irrigation in the non-growing season (DF) in southern Xinjiang (SX) on soil physical and chemical properties. The results from 1985 to 2020 indicated that DI increased the soil organic matter (SOM) (7.39%/year), total nitrogen (TN) (7.09%), available phosphorus (AP) (4.71%) and available potassium (AK) (1.12%) contents in NX. The results of field sampling in 2022 presented that the average values of SOM, AK content and pH in NX were 10.24%, 76.86% and 5.24% higher than those of SX, respectively, which validated our analysis of 1985 to 2020. Additionally, the integrated soil fertility index (IFI) trends confirmed that soil fertility in NX was higher than SX: NX showed sustained improvement (1985-2022), whereas SX fertility declined post-2009. In conclusion, NX has demonstrated superior soil fertility and nutrient retention compared to SX over the past thirty-five years under the influence of irrigation patterns, drip irrigation may represent a more sustainable long-term agricultural strategy than traditional flood irrigation in this region.