Huang Qiao-Yi, Lin Bi-Shan, Rao Guo-Liang, Dai Wen-Ju, Li Ping, Wu Yong-Pei, Huang Jian-Feng, Zeng Zhao-Bing, Song Hui-Min, Tang Shuan-Hu, Zhang Mu, Xu Pei-Zhi
Key Laboratory of Plant Nutrition and Fertilizer in South Region, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation, Institute of Agricultural Resources and Environment, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
The Protection Center of Agricultural Environment and Cultivated Land Quality of Guangdong Province(Guangdong Rural Investment Center), Guangzhou 510500, China.
Huan Jing Ke Xue. 2023 Oct 8;44(10):5813-5822. doi: 10.13227/j.hjkx.202210088.
Soil acidification and low SOC are the main limiting factors in acidic paddy soils. Straw returning with lime is an effective measure to alleviate soil acidification and improve soil fertility; however, its interaction effects on SOC and carbon pool management are still unclear. To investigate the impact of straw returning with lime on the organic carbon pool of acidic paddy soil, field experiments were conducted on acidic paddy soil in Baiyun District and Huiyang District of Guangdong Province. The changes in soil total organic carbon (TOC), water-soluble organic carbon (DOC), active organic carbon (LOC), particulate organic carbon (POC), microbial biomass carbon (MBC), carbon pool index (CPI), stable organic carbon (IOC), carbon pool activity (), carbon pool activity index (CPAI), and carbon pool management index (CPMI) were analyzed under three treatments (CK, conventional fertilization; RS, straw returning+conventional fertilization; RS+L straw returning with lime+conventional fertilization). The results demonstrated that compared with that in CK, the TOC, LOC, POC, and MBC in the RS+L treatment were significantly increased by 10.24%-17.79%, 34.49%-44.37%, 19.27%-23.59%, and 33.36%-43.26%, respectively (<0.05). Compared with that in CK, the RS+L treatment significantly increased the DOC content during the early growth stage (15-45 days after transplanting) of rice (<0.05) but had no significant influence on the DOC content during the late growth stage of rice. Compared with that in RS, the TOC, LOC, POC, and MBC in the RS+L treatment were increased by 2.15%-6.95%, 1.17%-17.90%, 4.27%-8.65%, and 12.99%-14.53%, respectively. Compared with that in CK, the RS+L treatment significantly increased IOC and CPI by 8.32%-15.57% and 14.00%-20.00%, respectively (<0.05). Compared with that in the CK treatment, the RS treatment significantly increased CPI by 14.00%-18.00% (<0.05). No significant differences in , CPAI, or CPMI were detected among the different treatments. The soil pH in the RS+L treatment was significantly higher than that in the CK treatment (<0.05). No significant differences in rice yield were detected among the different treatments. Principal component analysis demonstrated that rice yield was primarily correlated with DOC, LOC, CPAI, and CPMI but its contribution to SOC and carbon pool management index was low. Principal component analysis also indicated that straw returning with lime could improve soil pH and nutrient contents of acidic paddy soil, driving the formation and accumulation of organic carbon fraction such as MBC and POC, thus boosting the increase in SOC. In conclusion, straw returning with lime is beneficial to the accumulation of MBC, POC, LOC, and IOC in acidic paddy soil to improve the content and stability of soil total organic carbon, which is an effective way to improve the carbon sequestration of acidic paddy soil.
土壤酸化和低土壤有机碳是酸性水稻土的主要限制因素。秸秆配施石灰还田是缓解土壤酸化和提高土壤肥力的有效措施；然而，其对土壤有机碳和碳库管理的交互作用仍不清楚。为探究秸秆配施石灰还田对酸性水稻土有机碳库的影响，在广东省白云区和惠阳区的酸性水稻土上进行了田间试验。分析了三种处理（CK，常规施肥；RS，秸秆还田+常规施肥；RS+L，秸秆配施石灰还田+常规施肥）下土壤总有机碳（TOC）、水溶性有机碳（DOC）、活性有机碳（LOC）、颗粒有机碳（POC）、微生物生物量碳（MBC）、碳库指数（CPI）、惰性有机碳（IOC）、碳库活性（）、碳库活性指数（CPAI）和碳库管理指数（CPMI）的变化。结果表明，与CK相比，RS+L处理的TOC、LOC、POC和MBC分别显著增加了10.24% - 17.79%、34.49% - 44.37%、19.27% - 23.59%和33.36% - 43.26%（<0.05）。与CK相比，RS+L处理显著增加了水稻生育前期（移栽后15 - 45天）的DOC含量（<0.05），但对水稻生育后期的DOC含量无显著影响。与RS相比，RS+L处理的TOC、LOC、POC和MBC分别增加了2.15% - 6.95%、1.17% - 17.90%、4.27% - 8.65%和12.99% - 14.53%。与CK相比，RS+L处理的IOC和CPI分别显著增加了8.32% - 15.57%和14.00% - 20.00%（<0.05）。与CK处理相比，RS处理的CPI显著增加了14.00% - 18.00%（<0.05）。不同处理间在、CPAI或CPMI上未检测到显著差异。RS+L处理的土壤pH显著高于CK处理（<0.05）。不同处理间水稻产量未检测到显著差异。主成分分析表明，水稻产量主要与DOC、LOC、CPAI和CPMI相关，但其对土壤有机碳和碳库管理指数的贡献较低。主成分分析还表明，秸秆配施石灰还田可提高酸性水稻土的土壤pH和养分含量，促进MBC和POC等有机碳组分的形成和积累，从而推动土壤总有机碳增加。总之，秸秆配施石灰还田有利于酸性水稻土中MBC、POC、LOC和IOC的积累，提高土壤总有机碳含量和稳定性，是提高酸性水稻土碳固存的有效途径。
