Fig. 2From: Enhancing nitrogen use efficiency and yield of maize (Zea mays L.) through Ammonia volatilization mitigation and nitrogen management approachesAmmonium (a) and nitrate (b) concentrations as affected by application of urea coated with S and S applied from gypsum. Values are means with standard error shown by vertical bars (n = 3). The solid arrows indicate the timing of N fertilizationBack to article page