Analysis of the Bacterial Communities in Continuous Cotton Fields of XinJiang Province

Long-term continuous cropping of cotton has caused dramatic soil-borne diseases in many places, leading to substantial agricultural losses. However, in some areas of Xingjang Province, the obstacles caused by continuous cotton cropping can spontaneously restore and maintain high yields of cotton for many years. To analyze the variable spectrum of soil bacterial communities and changes in the community structure in these spontaneously restored fields during cropping, soils at depths from 1 to 30 cm were sampled from cotton fields with a history of 0, 1, 3, 5, 10, 15 or 20 years of cotton cropping in the Akesu region of Xinjiang Province. The bacterial communities in these samples were studied using 165 rRNA-based polymerase chain reaction-density gradient gel electrophoresis (PCR-DGGE) with samples from uncultivated land as a control. The study demonstrated that the age of cotton fields had significant effects on soil bacterial diversity. Continuous cotton cropping exerted significant influences on the community structure of soil bacteria in Xinjiang Province, with an initial suppression effect on bacterial diversity.