Effects of plant growth-promoting rhizobacteria (PGPR) and different fertilizer combinations on yield and quality properties in cauliflower (Brassica oleracea L. var. botrytis)

Abstract

Purpose: This study was carried out to determine the influence of plant growth promoting rhizobacteria (PGPR) (Paenibacillus polymyxa RC14, Bacillus subtilis RC63 and Pseudomonas fluorescens RC77), organic chicken manure (OCM) (4000 kg/da), 3 levels of mineral fertilizer [(NPK1 (80 kg/ha N+50 kg/ha P+80 kg/ha K), NPK2 (160 kg/ha N+75 kg/ha P+160 kg/ha K) and NPK3 (200 kg/ha N+100 kg/ha P+200 kg/ha K)] and combination of these applications on growth, yield and quality of cauliflower under field conditions. Materials and Methods: Field experiments were conducted in randomized complete block design with four replications. Treatments were 1. Control (No Fertilizer Application; 0 kg /ha NPK), 2. NPK1 (80-50-80 kg / ha NPK), 3. NPK2 (160-75-160 kg /ha NPK), 4. NPK3 (200-100-200 kg /ha NPK), 5. PGPR, 6. Organic Chicken Manure (OCM), 7. PGPR + OCM, 8. NPK1+PGPR, 9. NPK2+PGPR, 10. NPK3+PGPR, 11. NPK1+ OCM, 12. NPK2+ OCM, 13. NPK3+ OCM, 14. NPK1+PGPR+ OCM, 15. NPK2+PGPR+ OCM, 16. NPK3+PGPR+ OCMResults: The highest curd weight and marketable yield were observed in NPK2+ OCM in 2014 while in NPK1+PGPR+OCM and NPK2+PGPR+OCM in 2015. NPK2+ OCM elevated the curd weight and marketable yield by 300% compared to the control in 2014. NPK1+PGPR+OCM increased the curd weight and marketable yield by 200% compared to the control in 2015. The highest TSS was observed in the control in 2014 whereas NPK1+PGPR+OCM gave the highest value. NPK treatments elevated the NO3 content of cauliflower curds. In 2014 the highest ascorbic acid content was determined in PGPR while the control gave the highest content in 2015. The highest oxalic acid contents were observed in NPK treatments. Furthermore, PGPR and OCM treatments generally reduced the oxalic acid contents of the cauliflower. Conclusion: NPK with OCM and PGPR applications could be advisable for the yield and quality parameters of cauliflower. Furthermore, the PGPRxOCM combination was advisable for efficiently using in organic agricultural production.