Response of Sweet Potato to Application of Pgpr and N Fertilizer

Abstract

This study was conducted to evaluate the response of sweet potatogrowth and yield to theapplication of PGPR and Nitrogen fertilizer.The field experiment was established under a design of Randomized Complete Block Designwith 3 replications.The inoculation for this study was comprised of 4 treatmentsand a control (Klebsiella sp. UPMSP9, Erwinia sp. UPMSP10,Azospirillumbrasilense SP7, Bacillus sphaericus UPMB10 and Uninoculated control) combinations with 3 levels of N fertilizer (0, 33, and 100 kg N ha^-1).The results indicated that the inoculation of the Klebsiella and supplied with 33kg Nha^-1increased sweet potato yield significantly compared to control. Similarly, the application of the bacterium Klebsiella and supplied with 33kg Nha^-1 recorded higher uptake of N, P and K compared to control. Soil P, K, Ca and Mg Concentrations were higher with PGPR and N application of 33kg N ha^{- 1} compared with the 100kg N ha^-1. The concentrations of IAA in soils inoculated with rhizobacterial isolates were significantly higher than uninoculated control. Highest IAA was observed with Klebsiella inoculation at33kg Nha^-1 fertilization rate. These findings showed that PGPR could be a potential inoculant at a reduced rate of N fertilizer for sweet potato production.