Biofuel Fermentation Broth As a Phosphorus Fertilizer for Snap Beans and Radish.

Phosphorus (P) is a key macronutrient essential for crop growth and development. The need of P fertilizers keeps growing and most of the fertilizers are made from nonrenewable mineral resources that will be run out in few decades. Crop production will have to face a potential P crisis in the near future. We need to explore other possible resources to overcome the challenges. Industrial wastes can provide alternative sources of P for plant industry. For example, fermentation broth from a cellulosic bioethanol process is rich in P. In this study, we started with collecting fermentation broth (including approximately 25% solid content) from a bioethanol process using phosphoric acid as a catalyst to break down cell wall structure and renewable sugarcane bagasse as the feedstock. This waste has approximately 300 mg/L available P and <1 mg/L nitrogen (N). It was diluted to 10 mg/L phosphorus pentoxide with water and then applied as P fertilizer to snap bean and radish plants grown in 1 gal pots, in a high tunnel, in Gainesville, Florida. Three fertilizer treatments (fermentation broth, commercial phosphate fertilizer, and control without P) were used in this study. The study was conducted using 4 replicates for each treatment and 5 pots in each replicate. The fertilizers were applied to the radish and snap bean plants in an eight-week period (twice a week) with the dosage of 100 and 120 lb/Acre P for the crop, respectively. Relative leaf chlorophyll concentrations were measured with a Minolta SPAD meter and it was an indicator of N use efficiency influenced by P availability. The yield was measured by yield weights after harvest. Results showed that fermentation broth was served as an excellent P fertilizer to achieve the highest yields and N use efficiency in the tested crops.