ABSTRACT

Calcareous, alkaline and kaolinite soils, despite external P fertilization, are low in plant extractable P because of their P fixing nature. Use of Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) are eco-friendly technologies for enhancing plant P nutrition and total crop production. However, use of potentially viable amongst numerous strains is of significant importance. In this study, we isolated and characterized AMF and PSB strains from berseem, wheat and pasture rhizosphere at ten agricultural soils and evaluated their P nutrition potential on maize crop grown in pots. Two PSB strains (URF-B-4 and NP-B-4) were identified for their highest population density (3.2 × 10⁸ g⁻¹ CFU) and P solubility index (3.02) whilst a total of four AMF strains (Glomus Hoi, Glomus claroideum, Glomus mossai, and Glomus intrardices) were isolated from berseem rhizosphere. The isolated strains were used both in the presence and absence of vermicompost (VC) in order to evaluate their potential in low and high carbon soils. Results revealed that selected strains of AMF and PSB in vermicompost (VC) pots (AMF+PSB+VC) significantly increased the plant height and roots dry biomass (by 41 and 55%, respectively). Soil OM, AB-DTPA extractable P, soil total N, plant P concentrations and N and P uptake were also significantly (P < 0.05) higher with AMF+PSB+VC followed by PSB+VC over rest of the treatments. The AMF+PSB resulted in significantly higher plant N concentration while the AMF root colonization and spores density and PSB population density were maximum for AMF+PSB+VC followed by AMF+PSB. Results concluded that for improved plant growth, nutrients availability/uptake, microbial status, and fertility of the alkaline and calcareous soils, only the efficient AMF and PSB strains (URF-B-4 and NP-B-4) application along with vermicompost would pay back significantly in addition to routine inorganic P fertilizer application.

摘要

钙质、碱性和高岭土土壤，尽管施了外部磷肥，但由于其固磷性质，植物可提取的磷含量很低。使用丛枝菌根真菌 (AMF) 和溶磷菌 (PSB) 是提高植物磷营养和作物总产量的环保技术。然而，在众多菌株中使用潜在可行的菌株是非常重要的。在这项研究中，我们从 berseem、小麦和牧场根际的 10 个农业土壤中分离并表征了 AMF 和 PSB 菌株，并评估了它们对盆栽玉米作物的磷营养潜力。鉴定出两种 PSB 菌株（URF-B-4 和 NP-B-4）的种群密度最高（3.2 × 10 ⁸ g ^-1 CFU）和 P 溶解度指数（3.02），而总共有四种 AMF 菌株（Glomus Hoi、Glomus claroideum、Glomus mossai和Glomus intrardices)从 berseem 根际分离。在存在和不存在蚯蚓堆肥 (VC) 的情况下使用分离的菌株，以评估它们在低碳和高碳土壤中的潜力。结果表明，在蚯蚓堆肥 (VC) 盆 (AMF+PSB+VC) 中选择的 AMF 和 PSB 菌株显着增加了植物高度和根干生物量（分别增加了 41% 和 55%）。土壤有机质、AB-DTPA 可提取磷、土壤总氮、植物 P 浓度以及 N 和 P 吸收也显着（P < 0.05），AMF+PSB+VC 和 PSB+VC 比其余处理高。AMF+PSB 导致植物氮浓度显着升高，而 AMF+PSB+VC 的 AMF 根定植和孢子密度和 PSB 种群密度最大，其次是 AMF+PSB。结果得出的结论是，为了改善植物生长、养分利用率/吸收，