The Effectiveness of Entrophospora colombiana and Scutellospora sp. Associated with Soybean on Phosphate Solubilization

Abstract

The maximum yield of soybean (5.72 g plant^-1) was obtained from plots treated with E. colombiana + TSP (triple superphosphate) at 30 kg P₂O₅ rai^-. Application of TSP increased soybean yield but the enhancement of VAMF (Vesicular Arbuscular Mycorrhizal Fungi) on soybean growth was reduced. The enhancement of VAMF in RPP (rock phosphate from Petchabun) and RPK (rock phosphate from Kanchanaburi) was significantly greater than in TSP treatment. Increasing the level of phosphate fertilizer reduced VAMF enhancement. The promotion of plant yield by E.colombiana together with RPP at 10 kg P₂O₅ rai^-1 was the greatest (2.63 g plant^-1) whereas the minimum promotion (0.06 g plant^-1) was found in Scutellospora sp. + TSP at 30 kg P₂O₅ rai^-1. P uptake was highly correlated with plant yield and the r² was 0.8984. The remaining available P and citrate soluble P were also highly correlated to each other at the r² of 0.9989. E. colombiana could solubilize P from rock phosphate better than that of Scutellospora sp. The
application of E. colombiana + RPP at 30 kg P₂O₅ rai^-1 may be an appropriate option to reduce cultivation cost. VAMF could solubilize P from cheaper rock phosphate and release enough available P to promote soybean yield as much as 4.95 g plant^-1 which was similar to the maximum yield of E. colombiana + TSP at 30 kg P₂O₅ rai^-1 treatment.