Nitrogen management effect on the production of sorghum

A two years field study was conducted to determine the optimumlevel of nitrogen with its efficient method of application for sorghumproduction during 1999 and 2000 at Arid Zone Research Institute, DeraIsmail Khan. Four nitrogen levels i.e. 0, 60, 90 and 120 kg ha-1 with twodifferent methods (soil application and foliar spray) were tested in thestudy. The experiment was laid out in split plot design with methods ofapplication in main plots and nitrogen levels in sub-plots On the basis oftwo years average data Leaf Area Index (LAI) was increased from 3.24 to4.75, 1000-grain weight from 30.04 to 32.05 g, grain yield from 2.92 to5.61 t ha-1 and stalk yield from 11.06 to 18.02 t ha-1 in treatmentsreceiving 90 kg N ha-1 as compared to control plots. The data indicatedthat yield and yield components of sorghum were increased with anincrease in N level irrespective of application method. However, theincrease was higher in lower levels of N as compared to succeedinghigher N level showing non-significant response in all traits except plantheight beyond 90 kg ha-1. Highly significant quadratic regression wasfound between all parameters and different N levels. In case of methodof application, soil applied nitrogen was found superior than foliar sprayin all the traits of growth parameters and yield. Significantly elevatedplant height (142.6 cm), LAI (4.32), grain yield (4.79 t ha-1) and stalkyield (4.79 t ha-1) were observed in case of N applied through soil ascompared with 141.1 cm, 4.20, 4.56 t ha-1 and 15.60 t ha-1, respectivelywhen N was applied as foliar spray. These results suggest that thenitrogen level of 90 kg ha-1 through soil application method was anefficient technique for increased crop yield of sorghum.