Increasing Phosphorus Use Efficiency with Organic Acids: Crop Yield.

Phosphorus (P) fertilizer is essential for profitable potato production. However, reduction of P fertilizer is warranted, as it is a source of nutrient pollution in surface waters (eutrophication leading to hypoxia) and is derived from non-renewable mineral resources. A new P fertilizer source, Carbond P® (CB; 7-24-0), increases P solubility in soil. Several field trials were conducted with potato (Solanum tuberosum L.), maize (Zea mays L.), sugarbeet (Beta vulgaris L.), and bean (Phaseolus vulgaris L.) in Idaho and Utah. Ammonium polyphosphate (APP; 10-34-0) and CB were applied at equal liquid rates (CB treated strips had ~30% less P applied) in concentrated band applications either before or at planting in close proximity to seed/seed piece (5-8 cm) in a strip plot design. Nitrogen rate was equalized with addition of urea ammonium nitrate. Application rates were 15-20 kg P₂O₅ ha^-1 for maize, bean, and sugarbeet and 44 kg P₂O₅ ha^-1 for potato. Despite using less P, all species resulted in increased tissue P concentration by an average of 12%. Yields were statistically equivalent for all species except potato, which had a 5.6 Mg ha^-1 increase in US No. 1 tubers with CB over APP. These results indicate that CB can increase P use efficiency without reducing yields.