Abstract:
To understand the quantity and quality situation of soil organic matter in the typical tobacco-growing regions, soil samples were collected in tobacco growing regions of three prefectures in Chongqing including Pengshui, Fengdu and Wushan. The contents of soil organic matter and its active ingredients were determined. The results showed that the contents of soil organic matter (SOM) ranged from 3.35 to 53.94 g/kg. The percentages of soil samples with SOM contents in the appropriate range (15-30 g/kg) for tobacco growing followed the order of Fengdu> Wushan> Pengshui, while the
CV for Wushan was higher than those of Fengdu and Pengshui. As the SOM was divided into high labile organic matter (HLOM), mid-labile organic matter (MLOM) and labile organic matter (LOM) with 33,167 and 333 mmol/L KMnO
4, respectively, their percentages in the SOM followed the order of Wushan>Fengdu>Pengshui, Fengdu>Wushan>Pengshui and Fengdu>Pengshui>Wushan, respectively. The content of HLOM, MLOM, LOM were significantly and positively correlated with the content of SOM, indicating that the active ingredient of soil organic matter may well reflect the dynamic changes of soil carbon, and therefore can be used as a indicator for the evaluation of soil fertility and soil quality.