A new sand pouch-plant infection technique for enumeration of rhizobia in soil

Abstract

A sand pouch-plant infection technique for counting most probable numbers of rhizobia in soil is described. Populations of <em>Rhizobium leguminosarum</em> bv. <em>trifoli</em> detected by the plant infection method performed in enclosed glass tubes or in sand pouches did not differ significantly. The described method was used to assess numbers of <em>R. leguminosarum</em> bv. <em>trifoli</em> (<em>R.l.t</em>.) and bv. viciae (<em>R.l.v.</em>) in 20 soils of Poland. Logarithms of the populations of <em>R.l.t.</em> in the tested soils ranged from not detectable level to 4.76 and those of <em>R.l.v.</em> from 2.23 to 5.84 in g1 of soil dry mass. Numbers of <em>R.l.t.</em> were significantly correlated with soil clay, C org, and total N contents but not with the soil pH (in KCI), while numbers of <em>R.l.v.</em> showed significant correlation only with the soil pH.