About Us | Help Videos | Contact Us | Subscriptions
 

Abstract

 

This article in SSSAJ

  1. Vol. 44 No. 3, p. 537-539
     
    Received: Sept 15, 1979
    Published: May, 1980


 View
 Download
 Alerts
 Permissions
 Share

doi:10.2136/sssaj1980.03615995004400030020x

Enumeration, Effectiveness, and pH Resistance of Rhizobium meliloti Populations in Oregon Soils1

  1. Lynn E. Barber2

Abstract

Abstract

The number of Rhizobium meliloti cells in the soil of alfalfa (Medicago sativa L.) fields and the effectiveness and pH resistance of strains of R. meliloti isolated from the soil were analyzed for their relationships to soil parameters. Soil samples were collected from three alfalfa-growing areas of Oregon and analyzed for pH, exchangeable H, soil bases, P, N, and organic matter content, and cation exchange capacity. The number of infective R. meliloti cells was estimated using the plant-infection assay. The nodulation effectiveness of each isolated R. meliloti strain was ranked using alfalfa growth response in tube culture and in comparison to uninoculated no N and N-amended controls. The ability of each strain to initiate growth in media adjusted to pH values of 4.5, 5.0, 5.5, 6.0, and 6.5 was determined. The number of R. meliloti cells in the soil was greater with increased soil pH and with decreased age of the alfalfa stand. Although the average ability of the strains of rhizobia to initiate growth at low pH increased with age of the alfalfa stand from which they were isolated, the strain effectiveness decreased with stand age. Average effectiveness of the strains increased with inoreased soil percent base saturation and with decreased soil exchangeable H, N, and organic matter contents.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America