Conversion of Pruning Waste into Biochar-based Organomineral Fertilizer to Improve Maize Yield and Phosphorus Use Efficiency

Open burning and dumping of pruning waste into landfills is detrimental for environmental quality.  This study was planned to convert pruning waste into biochar-based organomineral phosphatic fertilizer (BOMPF). A BOMPF with 20% P2O5 was prepared by enrichment of diammonium phosphate (DAP) in biochar of pruning waste. Five treatments (3 of BOMPF with 90%, 80% and 70% of recommended phosphorus, 1 of DAP and 1 as control with no phosphorus) were evaluated under pot trail using maize as test crop. Treatments were applied according to complete randomized design (CRD) with three replications of each treatment. Results demonstrated that BOMPF with 90% of the recommended phosphorus (P) significantly increased maize plant height, fresh shoot weight, root length, and fresh root weight by 20%, 76%, 25%, and 53%, respectively, as compared to the control. Likewise, treatment with 90% P as BOMPF also enhanced P contents (63%), P uptake (169%), K contents (34%) and K uptake (122%) and achieved 14.1% higher PUE as compared to DAP. It is concluded that application of P as BOMPF can significantly enhance PUE, maize growth and yield attributes than conventional DAP even with 10% less P. However, more field studies are needed for broader applicability of this technology.