Effects of land clearing for agriculture on soil organic carbon stocks in drylands: A meta-analysis

To improve our understanding of clearing natural ecosystems for cropland on soil organic carbon stocks in drylands, we searched for related peer-reviewed research papers published from 1980 to 2022 on the Web of Science (https://www.webofscience.com) and the Scopus Database (https://www.scopus.com) (accessed on 30th April 2022). Then, we screened papers for integrity, relevance, and scientific merit under the following criteria: (1) We made sure all studies were independent and based on field-measured data; (2) Each study had to report paired SOC stocks of cropland and adjacent natural ecosystems with the same or a similar suite of environmental factors; (3) Studies need to explicitly present results on SOC stocks or concentrations for certain depths and areas; (4) Studies have specified the types of natural ecosystems that were converted to cropland, which are used as criteria for defining CNEC types. Finally, we winnowed results to a total of 159 scientific journal articles, comprising 242 sites with 1379 paired soil layer observations from 601 paired soil profiles.

为加深对旱地自然生态系统垦殖为农田过程对土壤有机碳储量影响的认知，我们于2022年4月30日检索了Web of Science数据库（Web of Science，https://www.webofscience.com）与Scopus数据库（Scopus，https://www.scopus.com）中1980年至2022年发表的相关同行评议研究论文。
随后，我们依据以下标准对检索得到的论文开展完整性、相关性与学术价值筛选：
1. 所有研究均为独立研究，且基于实地实测数据；
2. 每项研究需报告农田与相邻自然生态系统的配对土壤有机碳（SOC）储量，且二者具有相同或相似的环境因子组合；
3. 研究需明确给出特定深度与区域的土壤有机碳储量或浓度结果；
4. 研究需明确说明被开垦为农田的自然生态系统（CNEC）类型，该类型将作为定义CNEC类型的标准。
最终，我们共筛选得到159篇学术期刊论文，涵盖242个研究样点，涉及601对土壤剖面，共计1379组配对土层观测数据。