College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Farming System, Ministry of Agriculture and Rural Affairs of China, Beijing 100193, China.
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
Sci Total Environ. 2022 Oct 10;842:156822. doi: 10.1016/j.scitotenv.2022.156822. Epub 2022 Jun 20.
Conservation agriculture (CA) can be an important strategy for improving soil organic carbon (SOC) and total nitrogen (TN). Numerous studies have examined SOC and TN dynamics in different cropping systems. However, there is some uncertainty regarding the relative impacts of some CA practices, and it is not always clear how other agricultural management, particularly nitrogen addition, interacts with these practices to influence SOC and TN sequestration. Thus, we conducted a global meta-analysis of 752 comparisons from 97 papers to analyze the impacts of nitrogen fertilizers and CA practices (namely crop diversification, minimal soil disturbance (no-tillage) and permanent soil cover), on SOC and TN content worldwide. Overall, our study showed the most significant increase of SOC [21.39 % (CI = 15.16 to 28.64)] and TN [54.34 % (CI = 26.19 to 96.69)] stock with CA practices compared to conventional practices in the 0-15 cm soil depth. It also showed a significant increase in SOC and TN stock with all the individual components of CA compared to conventional practices in the 0-15 cm soil depth. However, the impact of CA on SOC and TN is reduced in 0-60 cm depths compared to surface soil depths due to the limited input of crop residue deeper in the soil profile. Manure and manure mixed with mineral-N led to greater SOC sequestration [20.67 % (CI = 15.23 to 27.10) and 41.67 % (CI = 31.03 to 52.79), respectively] than mineral-N alone [9.08 % (CI = 6.44 to 11.83)]. Cropping systems that included legume residue decreased the C/N ratio. This highlights that adequate mineral-N fertilizer addition may also be required in conjunction with residue retention practices to improve SOC and TN content. Overall, these results show that CA systems that include legume residue and manure mixed with mineral-N have great potential to increase SOC and TN, particularly at 0-15 cm and 0-30 cm soil depth.
保护性农业（CA）可以是提高土壤有机碳（SOC）和总氮（TN）的重要策略。许多研究已经研究了不同种植系统中的 SOC 和 TN 动态。然而，对于某些 CA 实践的相对影响存在一些不确定性，并且并不总是清楚其他农业管理措施，特别是氮添加，如何与这些措施相互作用以影响 SOC 和 TN 固存。因此，我们对来自 97 篇论文的 752 个比较进行了全球荟萃分析，以分析氮肥和 CA 实践（即作物多样化、最小土壤扰动（免耕）和永久土壤覆盖）对全球范围内 SOC 和 TN 含量的影响。总体而言，与传统实践相比，我们的研究表明 CA 实践使 0-15 cm 土壤深度下的 SOC[21.39%（CI=15.16-28.64%）]和 TN[54.34%（CI=26.19-96.69%）]储量的增加最为显著。它还表明，与传统实践相比，CA 的所有单个组件在 0-15 cm 土壤深度下都使 SOC 和 TN 储量显著增加。然而，由于作物残茬在土壤剖面深处的输入有限，CA 对 SOC 和 TN 的影响在 0-60 cm 深度下会降低。与单独使用矿物-N 相比，有机肥和与矿物-N 混合的有机肥导致 SOC 固存增加[20.67%（CI=15.23-27.10%）和 41.67%（CI=31.03-52.79%）]，[9.08%（CI=6.44-11.83%）]。包括豆科植物残茬的种植系统降低了 C/N 比。这表明，为了提高 SOC 和 TN 含量，可能还需要与残茬保留措施相结合，适当添加矿物-N 肥料。总体而言，这些结果表明，包括豆科植物残茬和与矿物-N 混合的有机肥的 CA 系统具有增加 SOC 和 TN 的巨大潜力，特别是在 0-15 cm 和 0-30 cm 土壤深度。
