Abstract: 【Objective】 To investigate the effects of different modified cotton straw charcoal on the volatilization of nitrogen and fertilizer ammonia and soil physicochemical properties in Xinjiang grey desert soils in the hope of providing a basis for the return of cotton straw charcoal to improve low-yielding soils. 【Methods】 Xinjiang grey desert soil was taken as the test soil, an indoor incubation simulation experiment was conducted by using the closed method.Three nitrogen application levels of 0, 200 and 400 mg/kg were set, and cotton straw charcoal (no added cotton straw charcoal, unmodified cotton straw charcoal, monosodium glutamate waste modified cotton straw charcoal, wood vinegar liquid modified cotton straw charcoal and tartaric acid modified cotton straw charcoal) was applied uniformly at 2% soil weight.The rate of ammonia volatilization, the accumulation of ammonia volatilization and the correlation with the physicochemical properties of grey desert soils were studied for different modified cotton straw charcoal and different treatments of nitrogen application. 【Results】 The ammonia volatilization rate of each treatment reached the maximum value on day 1-8 after basal fertilizer application.After 61 days of indoor culture of ammonia volatilization in ash desert soil, compared with the ash desert soil treatment, the ammonia volatilization accumulation increased by 46.1%-99.8% in the treatment with different modified cotton-stalk carbon.Compared with unmodified carbon treatment, cotton stalk carbon modified by monosodium glutamate waste liquor and wood vinegar liquor significantly promoted ammonia volatilization of soil nitrogen fertilizer, while tartaric acid modified carbon had no significant difference.Adding modified cotton-stalk carbon could decrease pH, increase total nitrogen and organic carbon content and electrical conductivity of Xinjiang ash desert soil.Correlation analysis showed that the carbon modified by monosodium glutamate waste liquor and wood vinegar liquor promoted the evaporation of ammonia mainly in soil conductivity and soil total nitrogen content, while pH showed inhibition effect.pH and electrical conductivity of tartaric acid modified carbon had significant effects on soil application, but they did not reach a significant level (P >0.05).Soil total nitrogen content had a positive effect on ammonia volatilization, but was not significantly affected by organic carbon (P>0.05). 【Conclusion】 The properties of cotton-stalk charcoal are changed by using monosodium glutamate waste liquor, wood vinegar liquor and tartaric acid, and the tartaric acid modified charcoal has the best inhibition effect on ammonia volatilization in ash desert soil.