Seasonal responses of total antioxidant contents in cultivated bush tea (Athrixia phylicoides L.) leaves to fertilizer rates

Abstract

The objective of this study was to determine the seasonal effects of nitrogen (N), phosphorus (P) and potassium (K) fertilizer on total antioxidant content of cultivated bush tea (Athrixia phylicoides L.) leaves. Three independent trials of N, P and K were conducted per season i.e. autumn, winter, spring and summer. Treatments consisted of 0, 100, 200, 300, 400 or 500 kg/ha N, P or K replicated four times in a randomized complete block design. At harvest, leaves were freeze dried and ground for total antioxidant using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results of this study demonstrate that regardless of season, the application of N, P and K fertilizers quadratically increased total antioxidant content, with most of the increase occurring at 0-300 N, 300 P and 100 K kg/ha. Therefore, for improved total antioxidant contents in cultivated bush tea leaves, 300 N, 300 P and 100 K kg/ha N is recommended.