Sowing dates and irrigation regimes on growth, productivity and radiation use efficiency of winter maize (L.)Zea mays L.)

Phenological development, growth and yield of any grain crop are largely determined by availability of soil moisture, photo-thermal environments, intercepted photosynthetically active radiation (IPAR) and radiation use efficiency. Depending upon the harvesting period of previous rice crop, farmers sow winter maize in the region during November to January. Since development rate and duration of phenological stages are largely governed by prevailing temperatures; therefore, sowing date is one of the very important factors to obtain optimum productivity. Research was conducted to study phenological development rate, growth, yield, IPAR and radiation use efficiency of the winter maize under different photo-thermal environments and irrigation regimes, created by changing sowing dates and irrigation levels. The peak IPAR of 89.3, 87.6 and 85.5% were recorded by first, second and third sown crops, respectively and RUE of 1.55 to 2.02 g MJ were achieved under different treatments. Development rate was significantly correlated with maximum and minimum temperatures during emergence to tasseling and tasseling to maturity stages of the crop. Day length was found to be significantly correlated with reproductive stage of the crop but its effect on the phenology development rate in vegetative stage was not evident. Significant variation in biomass, leaf area, IPAR and RUE occurred among irrigation treatments. The last sown (January) crop expressed lower negative stress degree day (SDD) due to more dryness and less availability of soil moisture; as a result crop growth and productivity were reduced significantly.