Phosphorus Application and Rhizobia Inoculation on Growth and Yield of Soybean (Glycine max L. Merrill)
M. M. Akpalu *
Bolgatanga Polytechnic, Department of Ecological Agriculture, P. O. Box 767, Bolgatanga, Upper East Region, Ghana
H. Siewobr
Bolgatanga Polytechnic, Department of Ecological Agriculture, P. O. Box 767, Bolgatanga, Upper East Region, Ghana
D. Oppong-Sekyere
Bolgatanga Polytechnic, Department of Ecological Agriculture, P. O. Box 767, Bolgatanga, Upper East Region, Ghana
S. E. Akpalu
CSIR-FORIG, Bolgatanga P. O. Box 142, Bolgatanga, Upper East Region, Ghana
*Author to whom correspondence should be addressed.
Abstract
An experiment was conducted in the major and minor cropping seasons of 2012 and 2013 under field conditions at Bolgatanga Polytechnic, to study the effect of phosphorus fertilizer and Rhizobia inoculation on growth and yield of soybean using randomized complete block design and three replications. The treatments studied were: Soybean + phosphorus fertilizer + Rhizobia inoculation (+P/+I), Soybean + phosphorus fertilizer only (+P/-I), Soybean inoculated with Rhizobia (-P/+I) and the control-Soybean only (-P/-I). Results indicated that Phosphorus fertilizer application is required for shoot growth, pod and seed yield. Nodulation and root growth were significantly increased by Phosphorus + Rhizobia inoculation (+P/+I) but P fertilizer only did not enhance root growth. Dry matter accumulation was highest between onset of flowering and Podding. Grain yield was again highest for Rhizobia inoculation plus Phosphorus fertilizer (+P/+I) and Phosphorus fertilizer only (+P/-I) recording 7.61 t/ha and 7.30 t/ha respectively whiles Rhizobia inoculation only (-P/+I) and the control (-P/-I) produced the lowest grain yield (4.41 t/ha) and (3.80 t/ha) respectively
Keywords: Soybean, inoculation, nodulation, phosphorus, Rhizobia, protein energy malnutrition, soil fertility improvement