Increased phosphorus use efficiency in basil grown hydroponically with low phosphorus concentration and saline water

Phosphorus is one of the most important nutrients in agriculture for its physiological, ecological and economic implications. Phosphorus reserves are decreasing around the globe and therefore its price has been increasing in the last years. Phosphorus is subjected to many chemical phenomena in the root zone that make its management in cropping systems more and more difficult. In soilless culture, P can be monitored and managed with high precision in order to improve its uptake by roots and minimize its losses. In this experiment, basil (Ocimum basilicum L.) was grown hydroponically with different P (H₂PO₄^-) and NaCl concentrations in the nutrient solution: i) to evaluate the effects of P and salinity on plant yield and mineral nutrition, and ii) to verify the possibility to decrease P concentration without growth reduction. Three P concentrations (i.e., 0.25, 0.5, and 1.0 mol m^‑3) were combined with increasing NaCl concentrations (i.e., 5, 15, and 30 mol m^‑3) in the root zone. Plants faced the low concentration of P in the nutrient solution by increasing the root/shoot ratio. Plant yield was not influenced by P and NaCl levels. The agronomic use efficiency of P was significantly increased by the low P supply. These findings suggest that basil can be grown hydroponically at P concentration much lower than those currently used in commercial operations.