Phosphate Fertilization Increases Biomass, Photosynthetic Activity, and Nutrient Use Efficiency of Young Brazil Nut (Bertholletia Excelsa Bonpl) Plants

Phosphorus (P) reacts with soil minerals making it less plant available. Considering that the Amazonian soils are chemically poor and have low pH, collectively these properties contribute to increasing the P limitation, either in the native forest and plantations for sustainable production. Here, we investigated the effects of increasing P levels added in the substrate on growth and morpho-physiological traits of Brazil nut ( Bertholletia excelsa Bonpl.). The study was conducted in a greenhouse with 24-month-old saplings. The P treatments were as follows: the control (without P), 100, 200, 400 and 500 mg kg -1 of P addition to soil. Phosphate fertilization decreasing N:P ratio from 50 to 26. Phosphorus favored the photochemical efficiency of PSII ( F V /F M ) and, from the application of 200 mg kg -1 increase photosynthesis ( P N ) in 50%. Phosphorus enhanced light and nutrient use efficiency, except for P. Increases in biomass were observed from the addition of 200 mg kg -1 of P, and the maximum yield occurred at 306.2 mg kg -1 . Our findings reveal, on the one hand, the critical role of limitations of P on B. excelsa growth and taken together, our results allowed the identification of potential provided by P fertilization levels on the functional traits and growth of B. excelsa