Response to five different inoculation treatments has been determined in a three-year-old prairie area
established at the Becker Sandplain Experiment Station in Fall 2004. Seed inoculation was generally
ineffective, but overall legume numbers and biomass in the prairie restorations were enhanced by both
soil-applied granular and cover-crop applied inoculants, with soils collected from the prairie areas in
2007 also showing marked improvement in the soil quality traits Microbial biomass C and N as a result
of inoculation. When Dalea rhizobia were recovered from soil in the different prairie plots, and identified
using BOXA1R-PCR, only 2% of the strains from the seed inoculation treatment identified with the
inoculant strains, whereas 53% -100% of the rhizobia from soil in the other treatments identified with
these strains. Dalea plants inoculated with rhizobia recovered from soil and identifying with the inoculant
strains outyielded those inoculated with non-inoculant strains by more than 100%. In contrast, when
slow-growing rhizobia from Desmodium canadense were recovered from soil and characterized, only
13.7% of the strains identified with the inoculant strains used. Most were not intended for Desmodium
per se but identified with the inoculant strains intended for Chamaecrista fasciculata, the legume species
most evident in the first season after planting. Inoculation with high potency granular soil-applied
inoculants improves both the nodulation and establishment of prairie legumes, and the quality of the
prairie, but species differences in response to inoculation require further study, particularly relative to
host establishment pattern, host/strain compatibility, spatial variability in soil and environmental
influencesMinnesota Department of Transportatio