夏大豆土壤微生物有机碳及颗粒有机碳对不同耕作措施的响应

【目的】研究周年土壤不同层次碳对耕作措施的响应,为复播条件下进行有利大豆土壤固碳的合理耕作措施提供参考依据。【方法】在2017年大田滴灌条件下,设置翻耕覆膜(TP)、翻耕(T)、深松(ST)、免耕(NT)4种土壤耕作处理,研究不同耕作处理对不同土壤层次土壤总有机碳(SOC)、微生物有机碳(MBC)、土壤颗粒有机碳(POC)含量的影响。【结果】相对于T与TP处理,NT与ST处理均有利于增加0~10 cm表层土壤的SOC、MBC和POC的质量分数,但两者间无显著性差异。在10~30 cm耕作层,TP处理较比于其余三种处理,能保持土壤中SOC、MBC和POC的质量分数。但在土层深度30 cm以下,ST处理的MBC、POC质量分数逐渐与其余三种处理的差异性逐渐增大并呈显著性差异。在0~60 cm土层深度,微生物有机碳与颗粒有机碳占总有机碳的比例范围分别为1.29%~2.35%与17.81%~31.99%,并均在深度至60 cm的土层达到最高点,其占在总有机碳的比率为ST>TP>T>NT。【结论】深松和免耕均能够有效增加表层土壤的SOC、MBC和POC的质量分数,其中深松对土层深度30 cm以下的MBC、POC质量分数与比率具有显著提升,而在土层20~30 cm翻耕覆膜能够更好保持土壤中SOC、MBC和POC的质量分数。

Response of Soil Microbial Organic Carbon and Particulate Organic Carbon to Different Tillage Measures in Summer Soybean

【Objective】 To explore the response of annual carbon at different levels to tillage measures, so as to provide reference for rational tillage measures for carbon sequestration in soybean soils under multiple sowing conditions. 【Method】 Under field drip irrigation in 2017, four soil tillage treatments were set up, namely, tillage mulching (TP), tillage (T), subsoiling (ST) and no-tillage (NT). The effects of different tillage treatments on the contents of soil organic carbon (SOC), microbial organic carbon (MBC) and particulate organic carbon (POC) in different soil layers were studied. 【Result】The results showed that compared with T and TP treatments, NT and ST treatments were beneficial to increase the mass fractions of SOC, MBC and POC in 0-10 cm topsoil, and there was no significant difference. In the 10-30 cm tillage layer, TP treatment could better maintain the mass fractions of SOC, MBC and POC in soil than the other three treatments. However, fewer than 30 cm of soil depth, the differences of MBC and POC mass fractions between ST treatment and the other three treatments gradually increased and showed significant differences. At the depth of 0-60 cm, the proportion of microbial organic carbon and particulate organic carbon in total organic carbon ranged from 1.29% to 2.35% and 17.81% to 31.99%, respectively. The proportion of microbial organic carbon and particulate organic carbon in total organic carbon reached the highest point at the depth of 60 cm, and the ratio of microbial organic carbon to total organic carbon was ST > TP > T > NT.【Conclusion】In summary, both subsoiling and no-tillage can effectively increase the mass fraction of SOC, MBC and POC in the topsoil, and the mass fraction and ratio of MBC and POC of subsoiling were significantly improved at the depth of 30 cm. The soil layer 20-30 cm tillage mulching can better maintain the mass fraction of SOC, MBC and POC in the soil.