Bacterial and fungal cell-wall residues in conventional and no-tillage agroecosystems
Bacterial and fungal cell-wall residues in conventional and no-tillage agroecosystems
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DOI：
10.2136/sssaj1999.6351188x
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发表时间：
1999-09-01
影响因子：
2.9
通讯作者：
Elliott, ET
中科院分区：
文献类型：
--
作者：
Guggenberger, G;Frey, SD;Elliott, ET
农业管理措施已被证明会影响土壤中的分解者群落，与传统耕作（CT）系统相比，免耕（NT）系统有利于真菌。在这项研究中，我们研究了六个北美农业生态系统方面的影响NT与CT管理系统的微生物细胞壁残留物在表层土壤中的累积。我们用总氨基糖含量估计生活和分解微生物细胞壁质量在土壤中的葡萄糖胺和胞壁酸的含量分离真菌和细菌的贡献微生物来源的土壤有机质（SOM）。与真菌和细菌活生物量中存在的氨基葡萄糖和胞壁酸的估计值相比，这些化合物的总浓度（745-2076 mg氨基葡萄糖kg（-1）土壤和37-79 mg胞壁酸kg（-1）土壤）分别高出54至745倍和26至82倍。在三个地点，氨基葡萄糖胞壁酸的比例在NT土壤（32.0，30.0，42.2）显着超过了那些在各自的CT土壤（18.8，22.1，23.0），因为更高的富集氨基葡萄糖。这与真菌生物量，颗粒有机物碳（POMC），平均重量直径的水稳定性聚集体（MWD），和总有机碳（TOC）的较高值相吻合。聚集体大小类别的分析表明，额外的葡糖胺积累在>53毫米的聚集体，但不是在较小的颗粒。真菌衍生的葡萄糖胺的SOM的富集表明，菌丝细胞壁残留物的积累是一个重要的过程中，在三个NT农业生态系统，导致更高的SOM存储在表层土壤中的同时，在团聚体稳定性的增加。其他土壤，具有较低的粘土和粉砂含量，表现出在POM-C，MWD，和总氨基糖NT和CT管理系统之间没有显着差异。我们认为，在较低的粘土和粉砂含量的有益潜力NT隔离微生物来源的SOM是较低的，因为有限的物理稳定。
Agricultural management practices have been shown to influence the decomposer community in soils, with no-tillage (NT) systems favoring fungi as compared with conventional tillage (CT) systems. In this study, we examined six North American agroecosystems with respect to the effects of NT vs. CT management systems on the accrual of microbial cell-wall residues in surface soil. We used total amino sugar contents to estimate living and decomposing microbial cell-wall mass in soil and the contents of glucosamine and muramic acid to separate fungal and bacterial contributions to microbial-derived soil organic matter (SOM). Compared with estimates of glucosamine and muramic acid present in living biomass of fungi and bacteria, total concentrations of these compounds (745-2076 mg glucosamine kg(-1) soil and 37-79 mg muramic acid kg(-1) soil) were larger by factors of 54 to 745 and 26 to 82, respectively. At three sites, the ratios of glucosamine to muramic acid in NT soils (32.0, 30.0, 42.2) significantly exceeded those in the respective CT soils (18.8, 22.1, 23.0) because of a higher enrichment of glucosamine. This coincided with higher values for fungal biomass, particulate organic matter carbon (POMC), mean weight diameter of water-stable aggregates (MWD), and total organic carbon (TOC). Analysis of aggregate-size classes showed that the additional glucosamine accumulated in >53-mm aggregates but not in smaller particles. The enrichment of SOM in fungal-derived glucosamine suggests that the accrual of hyphal cell-wall residues is an important process in the three NT agroecosystems which leads to higher SOM storage in surface soil concurrent with an increase in aggregate stability. The other soils, having a lower clay plus silt content, exhibited no significant differences in POM-C, MWD, and total amino sugars between NT and CT management systems. We suggest that at lower clay plus silt contents the beneficial potential for NT to sequester microbial-derived SOM is lower because of limited physical stabilization.