施用蚓粪对滨海盐碱地土壤有机碳库及其稳定性的影响

为探讨施用蚯蚓粪后滨海盐碱地土壤有机碳库及其稳定性的变化。选择江苏省南通市如东县栟茶镇方凌垦区的滨海盐碱地,于2019年10月将蚯蚓粪以0(VC0)、25(VC25)、50(VC50)、100(VC100)、200(VC200) t/ha施用量一次性施于田间,2022年10月采集耕层(0 — 20 cm)土壤样品,测定其可溶性有机碳、钙结合有机碳、易氧化有机碳、颗粒态及矿物结合态有机碳的含量,计算碳库管理指数,并采用固体核磁共振波谱分析土壤有机碳的官能团结构。结果表明:与不施用蚯蚓粪相比,施用超过50 t/ha的蚯蚓粪后,土壤有机碳库变化显著,SOC含量增加了35 %—97 %,可溶性有机碳含量增加了27 %—104 %,钙结合有机碳含量增加了19 %—26 %,易氧化有机碳含量增加了6 %—94 %,颗粒态和矿物结合态有机碳分别增加了14 %—124 %和37 %—85 %,土壤碳库管理指数提高了6 %—92 %;土壤中脂肪族碳与芳香族碳的比值减小,烷基碳/O-烷基碳以及疏水碳/亲水碳的值增大,表明土壤有机碳的结构稳定性有所提升。综上,施用蚯蚓粪对提高滨海盐碱地土壤有机碳库及其稳定性具有显著作用,且在50和100 t/ha施用量下效果最佳。

Effects of vermicompost application on the organic carbon pool and its stability in coastal saline-alkaline soil

To investigate the effect of vermicompost application on organic carbon pool and its stability in coastal saline-alkaline soil. A field experiment was conducted in the coastal saline-alkaline soil with barley-maize rotation in Fangling Reclamation Area, Ben cha Town of Ru dong County, Jiangsu Province, and the vermicompost was one-time applied to the field with the rates of: 0 (VC0), 25 (VC25), 50 (VC50), 100 (VC100), 200 (VC200) t/ha in October 2019. In October 2022, soil samples from the topsoil layer (0 - 20 cm) were collected to determine the contents of dissolved organic carbon, calcium associated organic carbon, labile organic carbon, particulate organic carbon and mineral-associated organic carbon. The carbon pool management index was calculated, and the functional group structure of soil organic carbon was analyzed by solid-state nuclear magnetic resonance spectroscopy. The results show that: compared with no application of vermicompost, soil organic carbon pool changes significantly after application of more than 50 t/ha vermicompost, SOC content increases by 35 %-97 %, dissolved organic carbon content increases by 27 %-104 %, calcium associated organic carbon content increases by 19 %-26 %, and labile organic carbon content increases by 6 %-94 %. Particulate organic carbon and mineral-associated organic carbon increases by 14 %-124 % and 37 %-85 % respectively, and the soil carbon pool management index increased by 6 %-92 %; The ratio of Aliphatic C to Aromatic C decreased, and the values of Alkyl C/O-alkyl C and Hydrophobic C/Hydrophilic C increased, indicating that the structural stability of soil organic carbon was improved. In conclusion, the application of vermicompost has a significant effect on the improvement of soil organic carbon pool and its stability in coastal saline-alkaline soil, and the effect is the best under the application amount of 50 and 100 t/ha.