Performance of winter maize (Zea mays) hybrid to planting methods and nitrogen levels

The experiment was conducted during the crop years 2006–07 and 2008–09 to study the effects of various doses of nitrogen and planting methods on various physiological processes associated with nitrogen-use efficiency and productivity of winter maize (Zea mays L.). The treatments comprised 3 planting methods (bed, ridge and flat) and six nitrogen levels (0, 175, 200, 225, 250 and 275 Kg N/ha) with planting methods in the main plot and nitrogen levels in sub-plots. Biometrical parameters, viz plant height, leaf area, dry matter accumulation, crop growth rate, relative growth rate were maximum among the bed planted crop and at 250 and 275 kg N/ha. Yield attributes namely, bundle weight, straw yield, shelling percentage, harvest index, total grain yield, 1000-grain weight, were significantly higher in the bed planted crop and in the crop supplied with higher doses of nitrogen. Crop supplied with 250 and 275 kg N/ha took fewer days to anthesis and silking than the crop supplied with lower nitrogen doses. Biochemical parameters, viz chlorophyll content and activities of various enzymes (nitrate reductase, glutamine synthetase and acid invertase) estimated from the leaves at pre- and post-anthesis stage were also found to be maximum among the bed planted crop and the crop supplied with higher doses of nitrogen. Activity of these enzymes was negatively co-related to anthesis-silking interval (ASI), whereas a positive corelation was found with yield.