Ontogeny Growth and Radiation Use Efficiency of Canola (Brassica napus L.) Under Various Nitrogen Management Strategies and Contrasting Environments

Nitrogen management is vital in variable environments having different temperature and intercepted solar radiations (IPAR) with respect to high nitrogen demanding Canola crop. The study explored the significance of nitrogen management to enhance the utilization of incident solar radiation in context to variable climatic conditions. Five nitrogenous regimes (N-0 = control, N-1 = 30 kg ha(-1), N-2 = 60 kg ha(-1), N-3 = 90 kg ha(-1), N-4 = 120 kg ha(-1) and N-5 = 150 kg ha(-1)) and two nitrogen fertilizer application timings (M-1 = full dose at time of sowing and M-2 = half dose at sowing time and half at flowering time) were used to quantify ontogeny growth and radiation use efficiency of canola at three diverse locations i.e. Islamabad, URF Koont Farm and Multan during 2016-17 and 2017-18). The experiment was executed in the field by following RCBD (Randomized Complete Block Design) factorial which was replicated thrice. An increase of 25% radiation use efficiency (RUE) was observed by N-150 while 14% at Islamabad in comparison to N-30 and Multan respectively. Similarly, maximum value of leaf area index (LAI) i.e. 6.0 and crop growth rate (CGR) i.e. 16.37 g m(-2) day(-1) were obtained by N-150 at Islamabad with split application method. The results of the study revealed the role of nitrogen to improve the utilization of intercepted radiations resulting more biomass production under variable environments. N-150 treatment gave maximum RUE at all diverse location proving it best yielding nitrogen level.