Effect of biofilmed biofertilizer on plant growth and nutrient uptake of <em>Hevea brasiliensis</em> nursery plants at field condition

Abstract

Beneficial microbes through their direct and indirect mechanisms support plant growth in a sustainable manner. This study was conducted to understand the effect of biofilmed biofertilizer (BFBF) on dry matter production and nutrient uptake of Hevea brasiliensis nursery plants. The BFBF was formulated by phosphorus solubilizing bacteria Bacillus spp. and commonly found fungi Aspergillus spp. associated with H. brasiliensis rhizosphere. Rubber Research Institute of Sri Lanka (RRISL) recommended inorganic fertilizers were applied at the rates of 0%, 50% and 100% of the recommended level with and without the application of BFBF at a rate of 100 ml per rubber nursery plant monthly. Plant dry matter production, nutrient contents of plant parts and their nutrient uptake were determined before and after bud grafting stages. Results showed that many observed growth parameters; diameter, height, shoot dry matter, root dry matter and total dry matter were significantly higher in BFBF applied treatments compared to its respective non BFBF treatments. There was no consistent trend on the effect of BFBF on leaf nutrient contents at both growth stages. There were no significant differences with 100%F, 50%F+BFBF and 100%F+BFBF treatments in relation to total N, P and K uptake at before bud grafting stage and total N and K uptake at after bud grafting stage. At after bud grafting stage, significantly higher total P uptake was observed in T5 (50%F+BFBF) and T6 (100%F+BFBF) treatments (81 mg P/plant and 87 mg P/plant respectively) than in T3 (100%F) (64 mg P/plant) treatment. This study suggest that reduced amount of inorganic fertilizer with BFBF gave no significant difference or significantly higher values in relation to plant growth and total nutrient uptake of rubber nursery plants compared to recommended fertilizer application.