Tao Jingjing, Raza Sajjad, Zhao Mengzhen, Cui Jiaojiao, Wang Peizhou, Sui Yueyu, Zamanian Kazem, Kuzyakov Yakov, Xu Minggang, Chen Zhujun, Zhou Jianbin
College of Natural Resources and Environment, Northwest A&F University/Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, MOA, Yangling 712100, Shaanxi, China.
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China.
Sci Total Environ. 2022 Jun 15;825:154087. doi: 10.1016/j.scitotenv.2022.154087. Epub 2022 Feb 23.
The long-term stability of soil inorganic carbon (SIC) and its minimum contribution towards global C cycle has been challenged, as recent studies have showed rapid decreases in SIC stocks in intensive agricultural systems. However, the extent of SIC losses and its driving factors remains unclear. Here, we compared changes in SIC density (SICD) in Chinese croplands between the 1980s and 2010s. The SIC contents in 1980s were obtained from second national soil survey (n = 949) and published studies (n = 47). The SIC contents in 2010s were based on resampling of soil profiles from the same locations during 2019 and 2020 (n = 30), as well as data from published studies and national soil survey (n = 903). We found that Chinese croplands have lost 27-38% of SICD from the 0-40 cm soil layer and that the soil pH has decreased by 0.53 units over the past 30 years. These SIC losses increased with the ratio of precipitation (P) to potential evapotranspiration (PET) and most notably with nitrogen (N) fertilization. The SICD decreased greatly in humid and semiarid regions, and these losses were enhanced by high N fertilization rates; however, the SICD increased in very arid regions. This analysis demonstrates that the water balance and N fertilization are major drivers leading to dramatic losses of SICD in croplands and, consequently, to decreases in soil fertility and functions.
土壤无机碳（SIC）的长期稳定性及其对全球碳循环的最小贡献受到了挑战，因为最近的研究表明，集约化农业系统中SIC储量迅速下降。然而，SIC损失的程度及其驱动因素仍不清楚。在此，我们比较了20世纪80年代至21世纪10年代中国农田SIC密度（SICD）的变化。20世纪80年代的SIC含量来自第二次全国土壤普查（n = 949）和已发表的研究（n = 47）。21世纪10年代的SIC含量基于2019年至2020年期间对相同地点土壤剖面的重新采样（n = 30），以及已发表研究和全国土壤普查的数据（n = 903）。我们发现，中国农田0-40厘米土层的SICD损失了27%-38%，且在过去30年里土壤pH值下降了0.53个单位。这些SIC损失随着降水量（P）与潜在蒸散量（PET）的比值增加而增加，最显著的是随着氮肥（N）的施用而增加。在湿润和半干旱地区，SICD大幅下降，高氮肥施用量加剧了这些损失；然而，在非常干旱的地区，SICD有所增加。该分析表明，水分平衡和氮肥施用是导致农田SICD急剧损失、进而导致土壤肥力和功能下降的主要驱动因素。
