THE EFFECT OF NITROGEN AND PLANT DENSITY ON THE AGRONOMIC PERFORMANCE OF A SORGHUM HYBRID

THE EFFECT OF NITROGEN AND PLANT DENSITY ON THE AGRONOMIC PERFORMANCE OF A SORGHUM HYBRID

Abstract:

A field experiment was conducted at Samaru during the 1985 wet season with a view to determining the effect of nitrogen fertilization and plant density on the agronomic performance of sorghum hybrid SAMS0RG 31 (SSH5). The treatments that were tested in the study involved the factorial combinations of five nitrogen application rates (0, 30, 60, 90 and 120kg N/ha) and three plant population levels (34 000; 50 000 and 66 000 plants/ha). Of all the parameters considered in the present study stover yield, flag leaf area, number of leaves per plant and stand count at harvest responded to nitrogen application. However, grain quality in terms of grain crude protein content Increased by about 21% when nitrogen application rate was increased from 0 to 120 kg N/ha. Increasing plant population from 34 000 to 50 000 plants/ha increased grain yield while a further increase from 50 000 to 66 000 plants/ha decreased grain yield. Increasing plant population from 34 000 to 50 000 and from 50 000 to 66 000 plants/ha decreased grain weight per plant by 25.5 and 14.1%, respectively. Yield attributes such as panicle length and grain number per panicle decreased with increasing plant population. Variables which decreased slightly with increase in plant population include, thresing percentage, harvest index, grain: stover ratio, stem diameter and number of internodes. Grain quality in terms of per cent total nitrogen in the grain and crude protein content decreased with increasing plant population. Significant (P=0.05) nitrogen x population interactions were observed in respect of grain weight per panicle, 1000-grain weight, panicle length, flag leaf area, stover yield, number of panicles per m , number of grains per panicle, weight per panicle, panicle dry weight at 16 weeks after planting (WAP) and plant total dry weight at 12 and 16 WAP. Grain yield positively correlated with most of the important yield components such as 1000-grain weight (r=0.662), number of grains per panicle (r = 0.702), grain weight per panicle (r – 0.736), panicle yield (r = 0.975), and panicle weight (r = 0.290*). Of the parameters considered, flag leaf area, stover yield, leaf area index, number of leaves per plant and count at harvest responded to significantly to nitrogen application up to 120 kg N/ha on this soil. It, therefore, implies that fertilizer recommendations for grain sorghum may need to take into account the native soil nitrogen Status i.e., soil test result as well as the preceding crop(s) in the rotation. There was no significant response to plant population up to 66 000 plants/ha.

THE EFFECT OF NITROGEN AND PLANT DENSITY ON THE AGRONOMIC PERFORMANCE OF A SORGHUM HYBRID