Rice growth and chlorpyrifos residue on an alfisol as affected by endophytic and rhizospheric bacteria isolated using Aleksandrov medium
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1
Department of Soil Science, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami No. 36A Kentingan, Surakarta 57126, Indonesia
2
Undergraduate Program of Soil Science, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami No. 36A Kentingan, Surakarta 57126, Indonesia
3
Department of Plant Protection, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami No. 36A Kentingan, Surakarta 57126, Indonesia
Corresponding author
Vita Ratri Cahyani
Department of Soil Science, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami No. 36A Kentingan, Surakarta 57126, Indonesia
J. Ecol. Eng. 2025; 26(3)
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ABSTRACT
The intensive use of insecticides and chemical fertilizers in rice cultivation is a common practice which leads to environmental and health concerns. This study isolated endophytic and rhizospheric bacteria from organic and conventional paddy fields using Aleksandrov medium, to find bacteria which basically having functional capabilities as potassium solubilizers and screening them for further capability as plant growth promoters and insecticide biodegradation agents for supporting rice growth on an Alfisol treated with multivariant insecticides. Consecutive assessments were conducted after isolation, involved 1) in vitro assessment of functional capability, 2) in vivo assessment for the effect of the selected isolated to the growth of rice seedling on agarose medium treated with monovariant insecticide (chlorpyrifos) and multivariant insecticides (chlorpyrifos, chlorantraniliprole, thiamethoxam, and carbofuran), and 3) greenhouse pot experiment to confirm the effect of selected isolates to rice growth on an Alfisol treated with multi insecticides. Nine out of 11 isolates with distinct colony morphotypes, demonstrated the capability as plant growth promoters which also resistant to insecticide at the in vitro assessment. It was found that the three isolates of AElC-1, AElO-1, and ARsC-3 showed the consistent higher performance during consecutive assessments. The highest level of chlorpyrifos residue in soil and in plant tissue was indicated in the Control (+) treatment, while in the NPK treatment which showed the highest plant biomass, indicated the lowest chlorpyrifos residue in plant tissue, but the second high level of chlorpyrifos residue in soil after the Control (+). The treatment of 3 superior isolates demonstrated the range of chlorpyrifos residue in plant tissue was 0.098 – 0.101 mg/kg or higher than that in the NPK treatment but lower than that in the Control (+), while in soil the residue at the range 0.132 – 0.135 mg/kg which was lower than that in the NPK treatment and in the Control (+). The 3 superior isolates demonstrated superior capabilities in suppressing chlorpyrifos which potential to be used as soil and plant protecting agents especially in agricultural environments. Molecular identification by 16S rDNA sequencing revealed AElO-1 as Microbacterium sp., AElC-1 as Caulobacter sp., and ARsC-3 as Sphingomonas trueperi.