ZHAO Qingling, LI Qingcai, LI Yuanzhong, JI Yonghong, PANG Chengbao, SHEN Tao
( Lunan Geo-Engineering Exploration Institute of Shandong Province, Yanzhou 272100, China )

Abstract: Southern Ji’ning district, Shandong Province, China is famous as production bases for national commodity grain, high quality garlic, high quality rice and organic vegetables. As one of the most important parts of soil fertility in farmland ecosystem, organic carbon playsan important role in improving soil quality and raising yield of crops. Therefore, it’s of great significance to study the density and reserve of organic carbon in plowing layer soil. Herein, 79 samples of plowing soil in southern Ji’ning district were collected and their organic carbon contents were measured using element analyzer. According to the result, the densities of organic carbon were between 1.92 and 4.83 kg/m2, and the weighted average was 4.03 kg/m2, higher than the average of Chinese plowing layer soil value (2.97 kg/m2). The total reserve of organic carbon estimated by using soil type category was 4.57×109 kg, while the total reserve was 4.53×109 kg estimated by using soil utilization type. The organic carbon accumulation level in plowing layer soil of southern Ji’ning district was significantly impacted by human activity. The linear dependent coefficient between nitrogen content and organic carbon in plowing layer soil was 0.9249. Furthermore, accumulation level of organic carbon was also related to the scale of the straw that was returned back to soil. The result could not only provide support for further soil environmental quality assessment but also lay foundation for research on regional ecological balance.

Key words: soil; organic carbon; density; reserve; abundance index;plowing layer; Ji’ning

EARTH AND ENVIRONMENT Vol. 43, No.5 Tot No.307, 2015, Page 505-5