Temperature effects on cropland soil particulate and mineral-associated organic carbon are governed by agricultural land-use types
Chengji Li,
Min Ran,
Liangying Song,
Yuanyuan Zhang,
Aiwen Li,
Wenjiao Shi,
Wendan Li,
Jinli Cheng,
Bin Zhao,
Youlin Luo,
Qi Tao,
Yingjie Wu,
Xuesong Gao,
John P. Wilson,
Qiquan Li
Affiliations
Chengji Li
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Min Ran
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Liangying Song
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Yuanyuan Zhang
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Aiwen Li
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Wenjiao Shi
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Wendan Li
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Jinli Cheng
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Bin Zhao
College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
Youlin Luo
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Qi Tao
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Yingjie Wu
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Xuesong Gao
College of Resources, Sichuan Agricultural University, Chengdu 611130, China
John P. Wilson
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Spatial Sciences Institute, University of Southern California, Los Angeles, CA 90089-0374, USA
Qiquan Li
College of Resources, Sichuan Agricultural University, Chengdu 611130, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu 611130, China; Corresponding author.
Agricultural land use and temperature change can profoundly affect soil organic carbon (SOC), but their combined effects on regulating cropland SOC fractions over broad geographic scales remain poorly understood. Based on 871 topsoil (0–20 cm) samples collected from the Sichuan Basin of China, we used random forest model and partial correlations analysis to explore how the functionally distinct SOC fractions, including particulate and mineral-associated organic C (POC and MAOC), are affected by both agricultural land use and temperature over a large scale. The results show that POC accounts for 32.54 % of the total cropland SOC and soils with high SOC contents have larger proportions of POC. Cropland type is the dominant control of the two SOC fractions and regulates the impacts of other factors. The contents of soil POC and MAOC in dryland are much lower than that in paddy field and dryland-paddy rotation land. Significant correlations between mean annual temperature and the two SOC fractions are only found in dryland and dryland-paddy rotation land, while mean annual temperature has no impact on both POC and MAOC in paddy field. Meanwhile, the correlation coefficients between mean annual temperature and POC and MAOC for dryland decreased by 61.90 % and 69.23 %, respectively, and for dryland-paddy rotation land decreased by 28.00 % and 14.29 %, respectively, after removing correlations with net primary productivity. Additionally, correlation between mean annual temperature and POC is slightly higher than that between mean annual temperature and MAOC in dryland, while the reverse in dryland-paddy rotation land. These results suggest that the temperature effects on POC and MAOC are cropland type-dependent. To accurately predicting future cropland SOC change and reliably evaluate the potential contribution of cropland soil C sequestration, fraction-specific control mechanisms related to cropland type should be sufficiently considered in carbon models.
