This study investigates the effects of perennial grass species richness levels and consortium of three bacteria on properties of a slightly alkaline soil and on biomass production of grasses. Four species of perennial aromatic grasses namely: vetiver (Vetiveria zizanioides), lemongrass (Cymbopogon citratus), palmarosa (Cymbopogon martinii), and citronella (Cymbopogon winterianus) were planted in all possible combinations at one, two, three, and four species richness levels in a randomized block design with three replications and two treatments, these were PGPR⁺ (with plant growth promoting rhizobacteria) and without (PGPR⁻). Species and richness level specific changes in soil physicochemical properties: electrical conductivity (EC); bulk density (BD); total soil organic carbon (TOC); available nitrogen (N_av), microbial colony forming unit (CFU); microbial biomass carbon (MBC), and enzymatic alkaline phosphatase (ALKP) and dehydrogenase activity (DHA) were observed. The highest reduction in soil pH and EC and increase in soil TOC, CFU, N_av, MBC, and enzymes activities were found at two species richness levels of vetiver and lemongrass in both PGPR⁺ and PGPR⁻ plots followed by monoculture of vetiver. The highest annual total dry biomass 22.8 and 27.5 Mg ha⁻¹ was produced by monoculture of vetiver in PGPR⁻ and PGPR⁺ plots, respectively, with similar values at two species richness levels of vetiver and lemongrass in PGPR⁻ and PGPR⁺ plots. The highest plant carbon was found in vetiver monoculture and two species richness levels of vetiver and lemongrass. The soil carbon sequestration potential was highest at two species mixtures of vetiver–lemongrass and lemongrass–palmarosa as well.

中文翻译：

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多年生芳香草物种丰富度和微生物群落对边缘土地土壤特性和生物量生产的影响

这项研究调查了多年生草种的丰富度水平和三种细菌的聚生对弱碱性土壤特性和草的生物量产生的影响。分别以1、2、3、4种丰富度水平种植了香根草（Vetiveria zizanioides），柠檬草（Cymbopogon citratus），棕榈（Cymbopogon martinii）和香茅（Cymbopogon winterianus）四种。在一个随机区组设计，重复三次和两种处理，这些都是PGPR ⁺（与植物生长促进根际细菌）和不具有（PGPR ^-）。物种和丰富度对土壤理化性质的特定变化：电导率（EC）；堆密度（BD）; 土壤有机碳总量（TOC）；有效氮（N _av），微生物菌落形成单位（CFU）；观察到微生物生物量碳（MBC），酶促碱性磷酸酶（ALKP）和脱氢酶活性（DHA）。土壤pH值和电导率，提高了最高减少土壤TOC，CFU，N _AV在两个物种被发现，MBC和酶的活动香根草和柠檬草的丰富性水平都PGPR ⁺和PGPR ^-地块之后香根草的单一种植。最高年总干生物量22.8和27.5镁公顷^-1通过在PGPR香根草单一种植产生^-和PGPR ⁺曲线，分别与在PGPR两个物种丰富香根草和香茅的水平相似的值^-和PGPR ⁺地块。香根草单一栽培中的植物碳含量最高，香根草和柠檬草的两个物种丰富度水平最高。香根草-柠檬香茅和柠檬草-palmarosa两种混合物的土壤固碳潜力最高。