Storage and Vertical Distribution Characteristics of Nitrogen in the Continuously Cropped Cotton Field in Xinjiang Oasis, China

• Main Authors: JING Feng, GUO Cheng-zang, TAN Jian-xin, KANG Ya-long, CAO Jing-jing, TIAN Bao-geng, LIU Jian-guo
• Format: Article
• Language: zho
• Published: Agro-Environmental Protection Institute, Ministry of Agriculture 2015-12-01
• Series: Journal of Agricultural Resources and Environment
• Subjects: Xinjiang oasis; cotton; continuous cropping; total nitrogen storage; distribution characteristics
• Online Access: http://www.aed.org.cn/nyzyyhjxb/html/2015/6/20150605.htm

The objective of the experiment was to investigate the storage and vertical distribution characteristics of nitrogen in the continuously cropped cotton field in Xinjiang oasis. This experiment was conducted at the Shihezi University experiment station in Shihezi, China. The experiment consisted of seven continuous cropping periods(1, 5, 10, 15, 20, 25 years and 30 years) and three soil depths (0～20, 20～40 cm and 40～60 cm). Results showed that soil total nitrogen storage increased as the duration of continuous cropping increased, but the degree of increase of continuous cropping treatments were different, the soil total nitrogen storage initially increased obviously in the 5 years and 10 years treatment, and then increased slowly after 10 years. As for the growth rate, 0～60 cm depth soil nitrogen storage's growth rate showed initially decreased, then increased, and then stabilized as the duration of continuous cropping increased. Besides, soil total nitrogen content had significantly negative correlation with soil bulk density. As for different soil depths, the soil total nitrogen storage of each continuous cropping periods decreased as the soil depth increased, and surface soil(0～20 cm depth) nitrogen storage was higher than deeper soil (20～40 cm depth and 40～60 cm depth). Besides, with the year of continuous cropping increased, the properties of surface-aggregation of total nitrogen storage in 0～60 cm depth soil became more obviously. As for different years of continuous cropping, with the year of continuous cropping increased from 5 years to 10 years, the soil nitrogen storage of three soil depths(0～20, 20～40 cm and 40～60 cm) were all increased, however, after long-term continuous cropping(10～30 years), the soil nitrogen storage of 20～40 cm depth increased gradually, but the 40～60 cm depth increased more slowly. In a word, the nitrogen of Xinjiang oasis cotton field was nitrogen sink, besides, continuous cropping could increase the soil nitrogen storage of 0～20, 20～40 cm and 40～60 cm depth, improve the soil nitrogen supplying capacity in the continuously cropped cotton field in Xinjiang oasis.