Interactive Effect of Plant Spacing and Phosphorus Concentration on Yield and Yield Components of Soybean (Glycine max. L.)

Abstract

Determination of the optimum plant population necessary for optimum yield is a major agronomic goal. Phosphorus nutrition is the main and most common constraint behind poor soybean productivity. A field experiment was conducted at Ibadan  Nigeria (transition between Rain forest and Guinea savannah zone)during 2015 cropping season to evaluate the effect of Phosphorus application and soybean plant population on the productivity of soybean The trial was laid out in a Randomized Complete Block Design (RCBD) with split plot arrangement, replicated three times. The main plots consisted of four Phosphorus (P)  levels (0, 20, 40 and 60 kg/ha) while four soybean populations (666700, 333333, 222200 and 166700 plants/ha) were the sub plots. Data collected include: number of branches, number of pods produced per plant, actual grain yield, seed weight, number of seed per pod, pod length and threshing percentage. Data collected were subjected to analysis of variance and significant means separated using Least Significant Difference (p<0.05). It was discovered that application of 60kg P/ha produced significantly (p=0.05) higher soybean yield (1103. kg/ha) with a yield advantage of 53.33% over Zero kg P /ha.  also, plant population of 222200 plants/ha had significantly (p=0.05) higher soybean yield (1,188kg/ha) with a yield advantage of 33.33% and 18.01% over 666700 and 333333 plants/ha respectively. It was concluded that combination of 60kg P/ ha planted at 15 cm spacing produced optimum soybean yield and yield components. Hence, application of 60kg/ha of Phosphorus to soybean planted at15 cm is recommended for optimum yield and yield components of soybean.