Table 4.

Frequency of α- and ^β-rhizobia isolated from root nodules of soybean at different ecosystems in Venezuela.

Soil-sampling sites	Ecosystem	Soil type	Legume history	Frequencies (%) of α- and β-rhizobia in different soils
				α-rhizobia	β-rhizobia**
Amazonas	Rainforest	Oxisol	Phaseolus sp., Fabaceae*	4.5a	4.5
Apure	Floodplain	Inceptisol	Fabaceae*	0	6.8
Aragua	Valley, no fertilizer	Inceptisol	Vigna sp., Canajus sp., Arachis sp.	13.6a,b	6.8
Aragua	Valley with fertilizer	Inceptisol	Phaseolus sp., G. max	15.9a,b	2.3
DC (Caracas)	National Park in the city	Alfisol	Fabaceae*	0	4.5
Falcon	Arid desert	Aridisol	Fabaceae*	0	4.5
Guárico	Savanna	Vertisol	—	0	6.8
Lara	Xerophilic ecosystem	Vertisol	Phaseolus sp.	2.3b	6.8
Miranda	Mountain	Alfisol	Fabaceae*	0	2.3
Trujillo	Andes	Ultisol	Fabaceae*	4.5b	9.1
Anzoátegui	Savanna near the coast	Ultisol	G. max	4.5a	0
			Total % of frequencies	45.3	54.4

Fabaceae^*: It includes unknown genera of trees, shrubs, and perennial or annual herbaceous plants.

^aIt was classifiedas the genus Bradyrhizobium.

^bit was related to the genus Rhizobium.

β-rhizobia^**: all isolates related to the genus Burkholderia or Paraburkholderia.