Pang Jing-Wen, Bu Chong-Feng, Guo Qi, Ju Meng-Chen, Jiang Man, Mo Qiu-Xia, Wang He-Ming
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1755-1763. doi: 10.13287/j.1001-9332.202207.017.
As an important soil cover in deserts, biological crusts play a central role in ecosystem function such as nutrient cycling, nitrogen fixation, and carbon sequestration. Many biological crust organisms could fix CO through photosynthesis to improve soil organic carbon content. There is a knowledge gap in the origin of soil organic carbon (SOC) from biological crusts on a regional level, which restricts the prediction of soil carbon pool. Based on 45 plots in the Mu Us sandy land (42200 km), we measured the SOC content and soil organic carbon density (SOCD) of two types of typical biological crusts (moss crusts, algal crusts) and their underlying soils, and analyzed together with the climate data, soil and vegetation factors to investigate the spatial distribution characteristics and controlling factors of organic carbon of biological crusts at the regional scale. The results showed that: 1) biological crusts significantly increased SOC and SOCD compared with bare ground. Moss crusts and the underlying SOC (4.93 g·kg) and SOCD (0.41 kg·m) were higher than those of algal crusts (1.89 g·kg, 0.18 kg·m). 2) On the regional scale, the SOC and SOCD of biological crusts had clear spatial distribution characteristics, demonstrating a banded distribution and block mosaic from northeast to central and west to southeast. 3) The SOC and SOCD of biological crusts and their underlying soils were mainly affected by climate, soil and vegetation conditions, while the main controlling factors depended on the types of biological crusts. The SOC and SOCD of moss crust were controlled by annual maximum temperature and potential evapotranspiration, whereas those of algal crusts were controlled by water vapor pressure.
作为沙漠中重要的土壤覆盖物，生物结皮在生态系统功能中发挥着核心作用，如养分循环、固氮和碳封存。许多生物结皮生物可以通过光合作用固定二氧化碳，以提高土壤有机碳含量。在区域层面上，生物结皮土壤有机碳（SOC）的来源存在知识空白，这限制了对土壤碳库的预测。基于毛乌素沙地（42200平方公里）的45个样地，我们测量了两种典型生物结皮（苔藓结皮、藻类结皮）及其下层土壤的SOC含量和土壤有机碳密度（SOCD），并结合气候数据、土壤和植被因素进行分析，以研究区域尺度上生物结皮有机碳的空间分布特征和控制因素。结果表明：1）与裸地相比，生物结皮显著增加了SOC和SOCD。苔藓结皮及其下层土壤的SOC（4.93克·千克）和SOCD（0.41千克·平方米）高于藻类结皮（1.89克·千克，0.18千克·平方米）。2）在区域尺度上，生物结皮的SOC和SOCD具有明显的空间分布特征，呈现出从东北向中部、西部向东南部的带状分布和块状镶嵌。3）生物结皮及其下层土壤的SOC和SOCD主要受气候、土壤和植被条件的影响，而主要控制因素取决于生物结皮的类型。苔藓结皮的SOC和SOCD受年最高温度和潜在蒸散量的控制，而藻类结皮的SOC和SOCD受水汽压的控制。
