Root growth, soil water depletion, nitrogen uptake and yield of wheat in relation to irrigation and nitrogen application

Abstract

In a trial in 1984-85 with wheat cv. HD 2009 given 80 or 120 kg N/ha, the values for root penetration and root wt density (RWD) in different soil layers were higher with (a) irrigation at 50% soil water depletion than with (b) a single irrigation applied at the crown root initiation stage. The higher RWD with (a) resulted in greater soil water depletion, higher plant N content and N uptake, greater DM accumulation and higher grain yields and water use efficiency compared with (b). Yields with 80 and 120 kg N/ha were 2.85 and 3.02 t/ha, resp., in treatment (a) and 1.17 and 1.27 t in (b). Effects of N levels on RWD, N content and uptake are described. Yield was positively correlated with RWD at 80 d after sowing.