Assessment of Community Dynamics of Arbuscular Mycorrhizal Fungi in the Rice (Oryza sativa L.) Rhizosphere and Potential Application as Biofertilizer

Abstract

Arbuscular mycorrhizal fungi (AMF) have the potential to maintain the sustainability of rice cultivation via maintaining soil health. The objective of this study was to produce an AMF-based biofertilizer for the rice variety Bg350 using indigenous dominant species of AMF that are adapted to paddy wetland soil conditions in dry, wet, and intermediate zones in Sri Lanka and are co-inoculated with the bacterium Azospirillum. A pot experiment was carried out to evaluate the effectiveness of the produced biofertilizer using the rice variety Bg350. Treatments were inorganic fertilizer, compost, biochar, produced AMF-biofertilizer [1 kg of ground carrier material inoculated with 50 g of AMF propagules and 20 mL of 1.5 × 108 (CFU/mL) of Azospirillum], and the control. A two-factor factorial, completely randomized design was used under sterilized and non-sterilized soil conditions with four replicates. The genera Glomus, Claroideoglomus, and Aculospora were identified as the most common AMFs in paddy soil in all investigated sites. In the 9th week of sampling, AMF root colonization was positively correlated (p = 0.028) with spore density. In Sri Lanka, for the first time, the highest AMF colonization rates in rice were recorded at 36.40% in the roots of the Bg350 from the Gampaha district. AMF root colonization increased over sampling time and was different according to the interactive effect of fertilizer application and soil condition. The biometric parameters and yield-attributing characteristics were significantly higher in the rice plants grown in sterilized soil, independent of the tested treatments. The number of grains per panicle was significantly similar (p ≤ 0.05) in the compost, AMF-biofertilizer, and inorganic fertilizer added treatments. It can be concluded that application of paddy soil adapted AMF species as a biofertilizer increased rice plant growth, productivity, and yield.

Arbuscular Mycorrhizal Fungi and Higher Plants

“…Depending on the farmer's requirement, the customized AMF-based biofertilizers can be produced by mixing one or more AMF species with other beneficial microorganisms such as plant growth-promoting rhizobacteria (PGPR) and phosphate-solubilizing bacteria (PSB) (Karima and Samia 2020). As a conventional method of biofertilizer production, the selected AMF species are first multiplied using selective host plants on pot culture under greenhouse conditions called the trap culture method, and then, AMF root inoculums and spore-baring soil are introduced to the plant with a suitable carrier (Kalamulla et al 2022). Kalamulla et al (2022) revealed that the application of indigenous AMF genera Glomus, Claroideoglomus, and Acaulospora isolated from rice rhizosphere together with Azospirillum sp.…”

“…As a conventional method of biofertilizer production, the selected AMF species are first multiplied using selective host plants on pot culture under greenhouse conditions called the trap culture method, and then, AMF root inoculums and spore-baring soil are introduced to the plant with a suitable carrier (Kalamulla et al 2022). Kalamulla et al (2022) revealed that the application of indigenous AMF genera Glomus, Claroideoglomus, and Acaulospora isolated from rice rhizosphere together with Azospirillum sp. increased the biometric and yield parameters in rice plants similar to the application of compost and inorganic fertilizer to the rice cultivation.…”

Effect of Arbuscular Mycorrhizal Fungi on Lowland Rice Growth and Yield (Oryza sativa L.) Under Different Farming Practices

“…In the present study, a considerable amount of AMF colonization was reported (0-4.98%) in the non-inoculated controls (Figure 2), which is in agreement with Purakayastha and Chhonkar [32], Wangiyana et al [33], and Chareesri et al [12], who reported 2.6%, 3-5% and 7% of indigenous AMF colonization in non-inoculated rice plants, respectively. Similarly, Kalamulla et al [34] and Chen et al [35] have reported 36.40% and 19.5 ± 7.2% of natural AMF colonization rates from the rice farmer fields in Sri Lanka and China, respectively. Our experiment indicated that AMF colonization in different treatments was very low or did not seem to occur at all in the rice plant's initial stage (3WAT).…”

Soil biological quality in rhizosphere, growth, and yield of upland rice grown on acid soil after amended biochar enriched sap of Kappaphycus alvarezii

“…In this study, the total abundance of AMF spores in the rhizosphere of the local cultivar Wakawoundu upland rice cultivated on soil amended with K-sap enriched biochar was lower than without biochar (Table 1). Kalamulla et al (2022) reported that adding biochar significantly reduced the total abundance of AMF spores in the rhizosphere of rice cultivated on unsterilized soil. In this study, the lower AMF spore abundance was related to an increase in pH, organic-C, total-N, C:N ratio, available-P, Ca, Mg, and exchangeable K, and Si content in acid soils after two weeks of incubation of biochar enriched and not enriched with K-sap (Kilowasid et al 2023a).…”