Luan Haoan, Liu Yingru, Huang Shaohui, Qiao Wenyan, Chen Jie, Guo Tengfei, Zhang Xiaojia, Guo Suping, Zhang Xuemei, Qi Guohui
College of Forestry, Hebei Agricultural University, Baoding, China.
College of Agronomy, Hebei Agricultural University/North China Key Laboratory for Crop Germplasm Resources, Ministry of Education/State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.
Front Microbiol. 2022 Jul 25;13:953552. doi: 10.3389/fmicb.2022.953552. eCollection 2022.
Knowledge of the spatial-temporal variations of soil organic carbon (SOC) quantity and quality and its microbial regulation mechanisms is essential for long-term SOC sequestration in agroecosystems; nevertheless, this information is lacking in the process of walnut plantations. Here, we used the modified Walkley-Black method, phospholipid fatty acid analysis, and micro-plate enzyme technique to analyze the evolution of SOC stocks and quality/lability as well as microbial communities and enzyme activities at different soil depths in walnut plantations with a chronosequence of 0-, 7-, 14-, and 21-years in the Eastern Taihang Mountains, China. The results indicated that long-term walnut plantations (14-and 21-years) enhanced SOC stocks, improved SOC quality/lability (as indicated by the lability index), and promoted microbial growth and activities (i.e., hydrolase and oxidase activities) in the 0-40 cm soil layers. Besides, these above-mentioned SOC-and microbial-related indices (except for oxidase activities) decreased with increasing soil depths, while oxidase activities were higher in deeper soils (40-60 cm) than in other soils (0-40 cm). The partial least squares path model also revealed that walnut plantation ages and soil depths had positive and negative effects on microbial attributes (e.g., enzyme activities, fungal and bacterial communities), respectively. Meanwhile, the SOC stocks were closely related to the fungal community; meanwhile, the bacterial community affected SOC quality/liability by regulating enzyme activities. Comprehensively, long-term walnut plantations were conducive to increasing SOC stocks and quality through altering microbial communities and activities in the East Taihang Mountains in Hebei, China.
了解土壤有机碳（SOC）数量和质量的时空变化及其微生物调节机制对于农业生态系统中SOC的长期封存至关重要；然而，核桃种植园过程中缺乏此类信息。在此，我们采用改良的Walkley-Black方法、磷脂脂肪酸分析和微孔板酶技术，对中国太行山以东0年、7年、14年和21年时间序列的核桃种植园中不同土壤深度的SOC储量和质量/活性以及微生物群落和酶活性的演变进行了分析。结果表明，长期核桃种植园（14年和21年）增加了SOC储量，提高了SOC质量/活性（以活性指数表示），并促进了0-40厘米土层中微生物的生长和活动（即水解酶和氧化酶活性）。此外，上述与SOC和微生物相关的指标（氧化酶活性除外）随土壤深度增加而降低，而氧化酶活性在较深土壤（40-60厘米）中高于其他土壤（0-40厘米）。偏最小二乘路径模型还表明，核桃种植园年龄和土壤深度分别对微生物属性（如酶活性、真菌和细菌群落）有正向和负向影响。同时，SOC储量与真菌群落密切相关；同时，细菌群落通过调节酶活性影响SOC质量/活性。综合来看，在中国河北太行山以东，长期核桃种植园有利于通过改变微生物群落和活动来增加SOC储量和质量。
