School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; CESCRA, ICAR-Indian Agricultural Research Institute, New Delhi, India.
School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia.
Sci Total Environ. 2021 Jul 15;778:146286. doi: 10.1016/j.scitotenv.2021.146286. Epub 2021 Mar 8.
Microbial activity strongly influences the stabilization of soil organic matter (SOM), and is affected by the abiotic properties within soil aggregates, which tend to differ between land uses. Here, we assessed the effects of SOM and pore geometry on the diversity and activity of microbial communities within aggregates formed under different land uses (undisturbed, plantation, pasture, and cropping). X-ray micro-computed tomography (μCT) revealed that macro-aggregates (2-8 mm) of undisturbed soils were porous, highly-connected, and had 200% more macro-pores compared with those from pasture and cropping soils. While the macro-aggregates of undisturbed soils had greater soil organic carbon (SOC) contents and N-acetyl β-glucosaminidase, β-glucosidase, and phosphatase activities, those of cropped soils harboured more diverse bacterial communities. Organic carbon was positively associated with the porosity of the macro-aggregates, which was negatively associated with microbial diversity and positively associated with enzyme activity. Thus, the biophysical processes in macro-aggregates may be important for SOC stabilization within the macro-aggregates.
微生物活性强烈影响土壤有机物质（SOM）的稳定，并且受到土壤团聚体内部非生物特性的影响，这些特性往往因土地利用方式的不同而不同。在这里，我们评估了 SOM 和孔隙几何形状对不同土地利用方式（原状、种植园、牧场和种植）下形成的团聚体中微生物群落多样性和活性的影响。X 射线微计算机断层扫描（μCT）显示，原状土壤的大团聚体（2-8 毫米）是多孔的、高度连接的，并且比牧场和种植土壤中的大团聚体具有 200%更多的大孔隙。虽然原状土壤的大团聚体具有更高的土壤有机碳（SOC）含量和 N-乙酰-β-葡糖苷酶、β-葡萄糖苷酶和磷酸酶活性，但种植土壤中的细菌群落更加多样。有机碳与大团聚体的孔隙度呈正相关，与微生物多样性呈负相关，与酶活性呈正相关。因此，大团聚体中的生物物理过程可能对大团聚体中 SOC 的稳定很重要。
