Original scientific paper
https://doi.org/10.5513/JCEA01/23.4.3636
Minjingu phosphate rock solubilization and potential for use of Klebsiella variicola-MdE4 and Klebsiella variicola-MdG1 as biofertilizer for maize production
Damiano KWASLEMA
; Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, P.O. Box 3008, Chuo Kikuu, Morogoro Tanzania
Nyambilila AMUR
; Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, P.O. Box 3008, Chuo Kikuu, Morogoro Tanzania
Hamisi TINDWA
; Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, P.O. Box 3008, Chuo Kikuu, Morogoro Tanzania
Abstract
Limited solubility of the Tanzania’s Minjingu phosphate rock (MPR) in non-acidic soil conditions has held back
its potential for widespread use in agricultural production. This study was designed to isolate, characterize and test
phosphate-solubilizing bacteria for their potential to increase solubility of MPR and enhance maize plant growth
under field conditions. Ten out of 19 isolates showing greatest phosphate solubilization indices on a Pikovskaya agar
medium were further characterized for other plant-growth promoting traits including production of IAA, siderophores
and ammonia. Two of them, namely isolates-MdE4 and MdG1 substantially outperformed other isolates in phosphate
solubilization and production of IAA, ammonia and siderophores. The two isolates molecularly identified as Klebsiella
variicola-MdE4 and K. variicola-MdG1 produced up 701, 699 and 750, 680 µg/ml of soluble phosphate from tricalcium
phosphate and hard Minjungu rock phosphate, respectively. Additionally, Biorock P- a biofertilizer formulation containing
MdE4 and MdG1 co-cultured in a molasses-based modified broth medium retained most of the phosphate solubilizing
potential and other plant-growth promoting traits of MdE4 and MdG1. Co-application of MdE1 and MdG1-containing
“bio-rock P” and inorganic phosphate at 20 kg P/ha resulted in higher maize grain yield than that of positive control (40
kg P/ha) under field conditions. The two isolates- Klebsiella variicola-MdE4 and K. variicola-MdG1 have the potential for
use in a biofertilizer formulation for commercial field applications.
Keywords
rock phosphate biofertilizer; inoculant; plant growth promoting bacteria; biofertilizer formulation
Hrčak ID:
288318
URI
Publication date:
21.12.2022.
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