PHENOLOGY, GROWTH, AND GRAIN YIELD OF MAIZE AS INFLUENCED BY FOLIAR APPLIED UREA AT DIFFERENT GROWTH STAGES

Foliar urea application is considered an important factor affecting phenology, growth, yield, and yield components of maize. A field experiment was conducted to study effects of urea spray on Azam variety of maize (Zea mays L.) in Mardan district of the North West Frontier Province (NWFP) of Pakistan during 2005-06. The 5 x 4 factorial experiment was designed with five urea levels (U0 = control, U1 = 2, U2 = 4, U3 = 6 and U4 = 8% urea) applied to main plots and four application timings (T1 = at V9, T2 = V12, T3 = VT and T4 = R1 stages) assigned to subplots. Days to tasseling, silking, and maturity were delayed significantly when urea was applied at the rate of 6% and when applied at the V12 stage. Earlier tasseling, silking, and maturity were observed in urea control plots and in plots that received urea at the V9 stage. Plant height, leaf area, number of grains per cob and per line as well as (1000) grain weight, and grain and stover yields increased significantly up to the 6% urea level. Maize yield and yield components were higher when urea was applied at the V12 and VT stages than at the V9 and R1 stages. It is concluded that urea spray at the rate of 6% during the V12 stage would improve the grain yield and yield components of maize in the study area and contribute significantly to increased production.