MINERALIZATION CHARACTERISTICS OF ORGANIC CARBON IN SHORT-TERM RECONSTITUTED SOILS OF SOFT ROCK AND SAND

To study the effects of different proportions of soft rock added to aeolian sandy soil on organic carbon pools, a field plot experiment was carried out. The parameters related to soil organic carbon mineralization were fitted by first-order kinetic equation. The results showed that the organic carbon mineralization rate can be divided into two stages: a rapid decline of 1 8 days and a steady decline of 8 30 days. The organic carbon mineralization rate and cumulative mineralization showed a trend of C1 > C3 > C2 > CK. The k values of CK and C2 treatments were significantly higher than those of C1 and C3 treatments. The cumulative mineralization rate and C0/SOC value of C2 treatment were the minimum in complex ratio treatment. The wheat yield treated with C2 treatment was the highest and there was no significant correlation with mineralization parameters. It can be seen that 1 : 2 volume ratio of soft rock to sand can indirectly promote the accumulation of organic carbon and crop yield. Introduction The soil organic carbon pool in terrestrial ecosystems is about 3 times more than that of plant carbon pools (Smith et al. 2008). The organic carbon, exchanged between soil and atmosphere accounts for about two-third of the total carbon storage of surface ecosystems. A slight change in it will have certain impact on greenhouse gas emissions (Chhabraa et al. 2003, Degryze et al. 2004). Soil organic carbon mineralization is an important part of the carbon cycle in terrestrial ecosystems. The change of land resources caused by human activities often causes the changes in atmospheric CO2 concentration through the effects on terrestrial ecosystems. This in turn affects the carbon cycle and the climate change process (Stump et al. 2018). Therefore, in recent years, the research on soil carbon cycle by human activities has attracted much attention and has become the core issue of multidisciplinary research. In the arid and semi-arid areas of Shaanxi Province, Shanxi Province, Inner Mongolia and in other arid areas there are two important soil resources. These are the soft rock (soft rock) and aeolian sandy soil (sand) which undergo routine weathering. As a result, serious soil erosion and loose texture in the soil components do occur causing low nutrient content and poor soil structure. Chinese and foreign experts term this condition as “Earth Environment Cancer”. It can be seen that the geographical hazard of the soft rock and sand areas determines the urgency and difficulty of ecological restoration in the region (Wang et al. 2007). Han et al. (2012) studied the structure and physicochemical properties of sandstone and sand, and analyzed that the two resources can be *Author for correspondence: <djyjy9209@126.com. 1 Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi’an 710075, China. 2 Key Laboratory of Degraded and Unused Land Consolidation Engineering, the Ministry of Natural and Resources of China, Shaanxi, Xi’an 710075, China. 3 Shaanxi Provincial Land Consolidation Engineering Technology Research Center, Shaanxi, Xi’an 710075, China. 4 Shaanxi Key Laboratory of Land Consolidation, Xi’an 710064, China.