Increasing soil carbon (C) in arable soils is an important strategy to achieve sustainable yields and mitigate climate change. We investigated changes in soil organic and inorganic carbon (SOC and SIC) under conservation agriculture (CA) in a calcareous soil of the eastern Indo‐Gangetic Plains of India. The treatments were as follows: conventional‐till rice and wheat (CT‐CT), CT rice and zero‐till wheat (CT‐ZT), ZT direct seeded rice (DSR) and CT wheat (ZT‐CT), ZTDSR and ZT wheat without crop residue retention (ZT‐ZT), ZT‐ZT with residue (ZT‐ZT+R), and DSR and wheat both on permanent beds with residue (PB‐PB+R). The ZT‐ZT+R had the highest total SOC in both 0–15 and 15–30 cm soil layers (20% and 40% higher (p < .05) than CT‐CT, respectively), whereas total SIC decreased by 11% and 15% in the respective layers under ZT‐ZT+R compared with CT‐CT. Non‐labile SOC was the largest pool, followed by very labile, labile and less labile SOC. The benefits of ZT and residue retention were greatest for very labile SOC, which showed a significant (p < .05) increase (~50%) under ZT‐ZT+R compared with CT‐CT. The ZT‐ZT+R sequestered ~2 Mg ha⁻¹ total SOC in the 0–15 cm soil layer in 6 years, where CT registered significant losses. Thus, the adoption of CA should be recommended in calcareous soils, for C sequestration, and also as a reclamation technique.

中文翻译：

---

保护性农业对土壤有机碳和无机碳固存及不稳定性的影响：印度东部恒河平原钙质土壤上的稻麦种植系统研究

增加可耕土壤中的土壤碳（C）是实现可持续产量和缓解气候变化的重要战略。我们调查了印度东部印度恒河平原钙质土壤在保护性农业（CA）下的土壤有机碳和无机碳（SOC和SIC）的变化。处理方法如下：常规耕种水稻和小麦（CT-CT），CT水稻和零耕种小麦（CT-ZT），ZT直播水稻（DSR）和CT小麦（ZT-CT），ZTDSR和ZT没有作物残渣保留的小麦（ZT‐ZT），有残渣的ZT‐ZT（ZT‐ZT + R），DSR和DSR和小麦均在有残渣的永久性土壤床上（PB‐PB + R）。ZT-ZT + R在0-15厘米和15-30厘米土壤层中的总SOC最高（分别高20％和40％（p 分别小于CT-CT <0.05），而与CT-CT相比，ZT-ZT + R下各层的总SIC分别降低了11％和15％。非不稳定SOC是最大的池，其次是非常不稳定，不稳定和较不稳定的SOC。对于非常不稳定的SOC，ZT和残留物保留的好处最大， 与CT-CT相比，ZT-ZT + R显着提高（p <.05）（〜50％）。ZT-ZT + R在6年中在0-15 cm的土壤层中隔离了约2 Mg ha ^-1的总SOC，其中CT记录了明显的损失。因此，应建议在钙质土壤中采用CA进行固碳，并建议采用开垦技术。