Green bean (Phaseolus vulgaris L.) growth and yield as affected by chemical phosphorus fertilizer and phosphate bio-fertilizer
A field experiment was conducted at Khomam, Guilan province, northern Iran, to evaluate the effects of phosphorus rate and phosphate bio-fertilizer on growth and yield of green bean (Phaseolus vulgaris L.). The experimental design was a factorial arrangement of treatments based on a randomized complete block with four replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg ha-1 as triple superphosphate) and phosphate bio-fertilizer application (seed inoculated with phosphate bio-fertilizer containing Pseudomonas fluorescens strain P5 and strain p13, and non-inoculated (control). Analysis of variance showed that phosphorus rate and phosphate bio-fertilizer had significant effect on plant height, pod number per plant, pod yield and pod N and P concentration. The relationships between phosphorus application rate and pod number per plant and pod yield were well expressed by linear equations. Regardless of phosphate bio-fertilizer application, pod number per plant was significantly increased from 55 to 85 pods per plant as P application rate increased from 0 to 100 kg ha-1. Similarly, pod yield increased linearly with increasing P application rate from 0 to 100 kg ha-1. Regardless of phosphorus rate, pod number per plant and pod yield were significantly higher in plots that received phosphate bio-fertilizer compared to control plots. Pod number per plant and pod yield increased by 16% and 15%, respectively, when phosphate bio-fertilizer was applied. Based on the results of this experiment, P application at the rate of 100 kg ha-1 along with phosphate bio-fertilizer are recommended for obtaining the greatest pod yield in green bean.