Abstract:
A field experiment was conducted at Samaru – Zaria, during the 1996 wet season to study the effect of rate, time and method of nitrogen application on the growth and yield of upland cotton (Gossypium hirsutum L.) variety SAMCOT-9. The treatments comprised factorial combinations of four nitrogen rates (30,60,90 and 120kg N/ha), three nitrogen application times (3, 3 and 8, and 8 weeks after sowing) and two methods of nitrogen application (side dressing and single band placement) using the split plot design. Application of nitrogen fertilizer at the rate of 60kg N/ha significantly increased growth characters of cotton such as plant height, plant dry weight, leaf area index, number of bolls/plant, seed cotton yield, cotton seed yield, lint yield and seed index (100-seed weight) more than did any of the other nitrogen rates that were tested. Time of nitrogen application affected the yield and yield attributes of cotton. Split application of nitrogen at 3 and 8 weeks after sowing (WAS) produced a higher cotton yield than single dose application. Eventhough other rates and time of nitrogen application produced similar results, application of 60kg N/ha in split doses at 3 and 8 WAS appeared to be the more appropriate treatment for the cotton variety tested. Both methods of nitrogen application appeared to produce similar results although the side dressing method produced slightly higher values than the single band placement. A significant nitrogen time x method interaction on cotton seed yield showed that the combined application of 60kg N/ha at 3 and 8 WAS gave the highest cotton seed yield. The nitrogen method x rate interaction also supported this same conclusion. Positive correlation between cotton seed yield and each of the parameters tested, with the exception of number of nodes/plant, number of leaves/plant, plant dry weight, days to 50% flowering and days to 50% boll opening were observed.
EFFECT OF RATE, TIME AND METHOD OF NITROGEN FERTILIZER APPLICATION ON THE GROWTH AND YIELD OF COTTON (Gossypium hirsutum L.) VARIETY SAMCOT-9 AT SAMARU, NIGERIA
