Response of Sorghum [Sorghum bicolor(L.) Moench] to Phosphorus and Nitrogen Fertilization under Rainfed Conditions, Blue Nile State – Sudan*

Abstract

Two field experiments were conducted on a Typic
chromusterts, fine, smectitic, isohyperthermic soil series in the Damazin
Research Station farm during two seasons (2005/06 and 2006/07). The
objective was to investigate the effect of phosphorus (P) and nitrogen (N)
and their interactions on sorghum [Sorghum bicolor (L.) Moench] growth
and grain yield. A randomized complete block design with four replicates
was used to execute the experiments. Plant height, grain yield and dry
matter were significantly increased by N and P applications, in both
seasons.The average yield of sorghum grain in the two seasons was 0.6
tons ha-1 for the control and 4.4 tons ha-1 for the highest fertilizer treatment
(P 80 N80 ). There were mutually synergistic effects between N and P which
significantly (P<0.0001) promoted growth and yield of sorghum.
Phosphorus enhanced nitrogen uptake and nitrogen use efficiency and vice
versa. At all N applications, phosphorus use efficiency tended to decrease
with increase in the rate of P application. The highly significant response
of sorghum to P and N fertilizers warrant recommending their application
under the rainfed conditions of Damazin, Sudan.