Fig. 3. Available N as nitrate (NO₃–N) in soil at 0- to 40-cm depth in (a) 1998 and (b) 1999 at sowing (S), anthesis (A) or ear emergence (EE), and physiological maturity (PM) under no-tillage (NT) and conventional tillage (CT). 0 = 0 kg N ha^-1; 120S = 120 kg N ha^-1 at sowing; 120T = 120 kg N ha^-1 at tillering.