Department of Plant and Soil Science, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand.
Department of Highland Agriculture and Natural Resources, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand.
PeerJ. 2023 Jun 14;11:e15530. doi: 10.7717/peerj.15530. eCollection 2023.
As a method for sustainable agriculture, biofertilizers containing plant growth-promoting bacteria (PGPB) have been recommended as an alternative to chemical fertilizers. However, the short shelf-life of inoculants remains a limiting factor in the development of biofertilizer technology. The present study aimed to (i) evaluate the effectiveness of four different carriers (perlite, vermiculite, diatomite and coconut coir dust) on the shelf-life of S2-4a1 and R2-3b1 isolates over 60 days after inoculation and (ii) evaluate isolated bacteria as growth-promoting agents for coffee seedlings.
The rhizosphere soil-isolated S2-4a1 and plant-tissue-isolated R2-3b1 were chosen based on their P and K-solubilizing capacities and their ability to produce IAA. To evaluate the alternative carriers, two selected isolates were inoculated with the four different carriers and incubated at 25 °C for 60 days. The bacterial survival, pH, and EC in each carrier were investigated. In addition, coconut coir dust inoculated with the selected isolates was applied to the soil in pots planted with coffee (). At 90 days following application, variables such as biomass and total N, P, K, Ca, and Mg uptakes of coffee seedlings were examined.
The results showed that after 60 days of inoculation at 25 °C, the population of S2-4a1 and R2-3b1 in coconut coir dust carriers was 1.3 and 2.15 × 10 CFU g, respectively. However, there were no significant differences among carriers ( > 0.05). The results of the present study suggested that coconut coir dust can be used as an alternative carrier for S2-4a1 and R2-3b1 isolates. The significant differences in pH and EC were observed by different carriers ( < 0.01) after inoculation with both bacterial isolates. However, pH and EC declined significantly only with coconut coir dust during the incubation period. In addition, coconut coir dust-based bioformulations of both S2-4a1 and R2-3b1 enhanced plant growth and nutrient uptake (P, K, Ca, Mg), providing evidence that isolated bacteria possess additional growth-promoting properties.
作为可持续农业的一种方法，含有植物生长促进细菌（PGPB）的生物肥料已被推荐作为化肥的替代品。然而，接种剂的保质期短仍然是生物肥料技术发展的一个限制因素。本研究旨在：（i）评估四种不同载体（珍珠岩、蛭石、硅藻土和椰子纤维粉尘）对 S2-4a1 和 R2-3b1 分离株在接种后 60 天内保质期的影响；（ii）评估分离出的细菌对咖啡幼苗的生长促进作用。
根据其磷和钾的溶解能力以及产生 IAA 的能力，从根际土壤中分离出 S2-4a1，从植物组织中分离出 R2-3b1。为了评估替代载体，将两种选定的分离株接种到四种不同的载体中，并在 25°C 下孵育 60 天。研究了每种载体中的细菌存活率、pH 值和电导率。此外，将选定的分离株接种到椰子纤维粉尘中，并应用于种植咖啡的盆栽土壤中。在应用后 90 天，检查了咖啡幼苗的生物量和总 N、P、K、Ca 和 Mg 吸收量等变量。
结果表明，在 25°C 下接种 60 天后，S2-4a1 和 R2-3b1 在椰子纤维粉尘载体中的种群分别为 1.3 和 2.15×10 CFU g。然而，载体之间没有显著差异（>0.05）。本研究结果表明，椰子纤维粉尘可用作 S2-4a1 和 R2-3b1 分离株的替代载体。接种两种细菌分离株后，不同载体之间的 pH 值和 EC 存在显著差异（<0.01）。然而，在培养期间，只有椰子纤维粉尘的 pH 值和 EC 值显著下降。此外，S2-4a1 和 R2-3b1 的椰子纤维粉尘生物制剂均能促进植物生长和养分吸收（P、K、Ca、Mg），这表明分离出的细菌具有额外的生长促进特性。
