Abstract Unsustainable farming systems for a growing population in Sub-Saharan Africa stress natural resources and lead to soil degradation. Legume cultivation, however, promotes soil microbial communities and may help reverse soil degradation. The soil properties (pH, texture, C and nutrient contents) of a set of contrasting sites from two agro-ecological zones of Cameroon were determined. This study characterises the microbial activities and functioning in rhizosphere soils of the four legumes Phaseolus vulgaris L., Glycine max L., Arachis hypogea L. and Vigna subterranea L. in a laboratory incubation experiment. Ecological indicators (total respiration, microbial biomass determined as total phospholipid fatty acids, metabolic quotient) of soil health were quantified after microbial activation by 14C-glucose and related to site-specific parameters as well as to the effects of legume cultivation. Microbial activation after glucose addition was frequently site-specific. Cumulative glucose respiration increased over time, and glucose pulses repeatedly boosted glucose respiration and total respiration at all sites. The microbial biomass was lowest after the experiment in the soil from the High Guinean Savannah except for soils under soybean cultivation. Among the four legumes cultivated, only soybeans strongly increased microbial biomass in the High Guinean savannah reaching even the level of microbial biomass in Western Highland soils. The lowest metabolic quotient in soybean rhizosphere soil and lowest glucose respiration compared to the soils of other legumes suggests a high carbon use efficiency, presumably due to C limitation in the High Guinean Savannah. Abiotic soil properties (pH, clay content) strongly influenced microbial habitat properties and thus had a positive effect on the CO2 efflux, irrespective of glucose addition. Within the set of tested legumes, soybean cultivation can, therefore, be strongly recommended as a long-term sustainable crop to boost soil microbial functioning and probably also nutrient cycling, especially under low total organic carbon stocks.

中文翻译：

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豆科植物对喀麦隆两个对比鲜明的农业生态区土壤微生物活性和碳循环功能的影响

摘要 撒哈拉以南非洲地区不断增长的人口不可持续的耕作系统对自然资源造成压力并导致土壤退化。然而，豆类种植促进了土壤微生物群落，并可能有助于逆转土壤退化。确定了来自喀麦隆两个农业生态区的一组对比地点的土壤特性（pH 值、质地、C 和养分含量）。本研究在实验室孵化实验中表征了四种豆科植物菜豆、甘氨酸、花生和豇豆在根际土壤中的微生物活性和功能。生态指标（总呼吸、微生物生物量测定为总磷脂脂肪酸、在微生物被 14C-葡萄糖活化后，土壤健康的代谢商数被量化，并且与特定地点的参数以及豆类种植的影响有关。添加葡萄糖后的微生物活化通常是位点特异性的。累积葡萄糖呼吸随时间增加，并且葡萄糖脉冲反复促进所有部位的葡萄糖呼吸和总呼吸。实验后，除了种植大豆的土壤外，高几内亚大草原土壤中的微生物生物量最低。在种植的四种豆科植物中，只有大豆显着增加了高几内亚大草原的微生物生物量，甚至达到了西部高地土壤的微生物生物量水平。与其他豆科植物的土壤相比，大豆根际土壤中最低的代谢商和最低的葡萄糖呼吸表明碳利用效率很高，这可能是由于高几内亚大草原的碳限制所致。非生物土壤特性（pH 值、粘土含量）强烈影响微生物栖息地特性，因此无论是否添加葡萄糖，都对 CO2 外流产生积极影响。因此，在一组经过测试的豆类中，强烈建议将大豆种植作为一种长期可持续的作物，以促进土壤微生物功能和养分循环，尤其是在总有机碳储量较低的情况下。粘土含量）强烈影响微生物栖息地特性，因此对 CO2 外流产生积极影响，而与添加葡萄糖无关。因此，在经过测试的豆类中，强烈推荐大豆种植作为一种长期可持续的作物，以促进土壤微生物功能和养分循环，尤其是在总有机碳储量较低的情况下。粘土含量）强烈影响微生物栖息地特性，因此对 CO2 外流产生积极影响，而与添加葡萄糖无关。因此，在一组经过测试的豆类中，强烈建议将大豆种植作为一种长期可持续的作物，以促进土壤微生物功能和养分循环，尤其是在总有机碳储量较低的情况下。