Soil microbial communities in different rangeland management systems of a sandy savanna and clayey grassland ecosystem, South Africa
Soil microbial communities in different rangeland management systems of a sandy savanna and clayey grassland ecosystem, South Africa
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DOI：
10.1007/s10705-017-9832-3
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发表时间：
2017-02
影响因子：
3.1
通讯作者：
E. Kotzé;A. Sandhage-Hofmann;W. Amelung;R. Oomen;C. C. Preez-C.
中科院分区：
文献类型：
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作者：
E. Kotzé;A. Sandhage-Hofmann;W. Amelung;R. Oomen;C. C. Preez-C.
牧场的土壤养分供应取决于土壤微生物群落的维持和表现。在这项研究中，我们调查了不同的牧场管理系统如何影响土壤微生物群落的结构和功能的粘土草原和桑迪稀树草原生态系统，南非。这些生态系统在气候、土壤和植被方面各不相同，桑迪稀树草原生态系统较为干燥，并被灌木侵占。土壤取样连续和轮流放牧系统沿着梯度放牧压力增加。分析包括酶活性和磷脂脂肪酸（PLFA）。结果表明，与干旱的桑迪稀树草原生态系统相比，无论牧场管理措施如何，粘土质草地生态系统的酶活性和PLFA含量都有所升高，这可能是因为土壤质地在维持微生物群落方面发挥了重要作用。然而，当微生物活性归一化碳，氮和微生物生物量，特定的酶活性显着较高的桑迪草原生态系统，表明更有效的微生物在这里发挥作用。此外，在粘土草原生态系统中，这些微生物参数比其他化学或物理土壤性质对放牧压力更敏感，而在桑迪稀树草原生态系统中，情况并非如此。减少放牧对牧场的压力，由实行轮牧的商业农场主进行，似乎刺激了微生物的表现，从而刺激了微生物介导的营养矿化，对植物生长产生了积极的影响。
Soil nutrient supply in rangelands depends on the maintenance and performance of soil microbiological communities. In this study we investigated how different rangeland management systems affects the structure and function of soil microbial communities in the clayey grassland and sandy savanna ecosystems, South Africa. These ecosystems differ in climate, soil and vegetation, with the sandy savanna ecosystem being drier, and encroached by bush. Soils were sampled under continuous and rotational grazing systems along a gradient with increasing grazing pressure. Analyses comprised of enzyme activities and phospholipid fatty acids (PLFA). The results revealed that the clayey grassland ecosystem displayed elevated enzyme activities and PLFA contents compared with the drier, sandy savanna ecosystem, irrespective of the rangeland management practices, likely because soil texture played a significant role in maintaining microbial communities. However, when microbial activity was normalized to carbon, nitrogen and microbial biomass, specific enzyme activities were significantly higher in the sandy savanna ecosystem, indicating a more efficient functioning of microbes here. Furthermore, these microbial parameters were more sensitive to grazing pressure in the clayey grassland ecosystem than other chemical or physical soil properties, whereas in the sandy savanna ecosystem this was not the case. Decreasing the grazing pressure on rangeland, as, e.g., done by commercial farmers practicing rotational grazing, appeared to stimulate microbial performance and thus microbial mediated nutrient mineralization with positive consequences on plant growth.