| Tarim basin of south Xinjiang is one of the most important cotton planting area in China,but the information about N fertilization practice in the cotton fields is lacking.In order to make clear the situation of N fertilization,an investigation was conducted in Cele and Yuli County of Xinjiang Uygur Autonomous Region in 2002-2003.The results show that the amounts of N fertilizer applied to cotton fields were much discrepant among different farmers.The average N fertilization rate was 426~430 kg/hm2,and the phenomena of excessive N fertilizer application were rather popular.The proportion of farmers with excessive N fertilizer application was 39.5% in Cele and 72.8% in Yuli,whereas there were 6.2%~7.9% of farmers with deficient N fertilizer.The farmers in Cele utilize more N fertilizer as top dressing,while the farmers in Yuli utilize more N fertilizer as basal fertilization.There was no relationship between the yields of seed cotton and total N fertilizer or mineral N fertilizer in both Cele and Yuli.The results of N equilibrium analysis showed that the average amount of N surplus in Cele and Yuli was 87~248(kg/hm2,) and the average residue Nmin in 0~90 cm soil profile after harvest was mostly less than 100(kg/hm2.) |