Investigating the effect of Aspergillus niger inoculated press mud (biofertilizer) on the potential of enhancing maize (Zea mays L.) yield, phosphorous use efficiency, and phosphorous agronomic efficiency

The world is facing tremendous challenges in tackling waste diversion from landfill to resource recovery. Conversion of organic waste into biofertilizer would reduce its environmental impacts by improving soil nutrient contents level and decreasing the requirements of mineral fertilizer (MF). Phosphorus (P) is the primary least available mineral in many cropping environments. The current study was aimed to isolate an efficient P-solubilizing fungi and to investigate its influence on total organic carbon (TOC), C/N ratio, total nitrogen (TN), total phosphorous (TP), total potassium (TK), and germination index (GI) of press mud to convert into biofertilizer. P from biofertilizer was then evaluated in different treatments in terms of maize biological yield, grain yield, P use efficiency (PUE), and P agronomic efficiency (PAE) in comparison to MF. Among seven P-solubilizing fungal isolates, A. niger was selected for its highest P-solubilizing activity in solid (1.5 cm) and liquid media (389 ug/ml) by solubilizing insoluble tricalcium phosphate (TCP). It was also found to mobilize zinc (Zn) from insoluble zinc oxide (ZnO). Bio-augmentation of press mud with A. niger shortens maturity period, improved nutrient contents and GI. Analysis of maize in different treatments revealed that P from mineral and biofertilizer enhanced crop yield. The competency of treatments was measured on higher PUE and PAE. Higher grain yield and harvest index (HI) were achieved in T5 (100%Org+50%MF) containing a higher amount of P from mineral and biofertilizer. However, higher PUE and PAE were found in the order T6>T5>T2>T3>T4>T1, demonstrating the importance of integrated and balanced use of fertilizers.