Changes in nutrient content of grey desert soil with different long-term fertilization methods

Based on a long-term field experiment at Fukang Ecological Station of Chinese Academy of Sciences, this study investigates the dynamic changes in soil nutrient content with different long-term fertilization methods in gray desert soil, a typical soil in arid regions. The soil samples are collected from the plow layer (0-20 cm) at five randomly selected points within each plot subjected to different fertilization treatments:1) no fertilization control; 2) chemical fertilizer alone; 3) chemical fertilizer + straw incorporation; and 4) chemical fertilizer + organic manure. The analyzed parameters include soil organic matter (SOM), available nitrogen (AN), available phosphorus (AP), and available potassium (AK). After 15-19 years of continuous fertilization, except for a slight decrease in AK, the contents of SOM, AN, and AP have increased across all treatments and generally stabilized. Compared with the no-fertilizer control, all fertilization treatments have significantly enhanced the levels of SOM, AN, and AP. Among the fertilization methods, chemical fertilizer + straw incorporation (300 kg/hm²) results in the highest SOM content; while chemical fertilizer + organic manure leads to the highest levels of AP and AN. There is a significant positive correlation between AN and SOM content. It is concluded that chemical fertilizer combined with straw incorporation greatly promotes the accumulation of organic matter in gray desert soil. Chemical fertilizer combined with organic manure (pure pig manure) significantly enhances the content of AN and AP, thereby improving crop yield and soil quality of oasis farmland.