This mixture was characterized by a pH of 5.4 (10 g soil in 25 mL water) and with N, P and K levels of 45.38, 5.3 and 40 mg kg-1, respectively. 2.3 Nutrient addition A nutrient solution including N, P and K was used in the fertilized treatment to achieve levels of 150 mg kg-1 N, 32.23 mg kg-1 P and 40.67 mg kg-1 K (using a triple-17 formulation including NH4NO3, NHPO4 and KNO3 as a nutrient source