Roadside Revegetation

IMPLEMENTATION GUIDES
Soil on restoration sites, however, may not contain the proper species of bacteria to form a
symbiotic partnership with the plant. This is particularly true for compacted soils and those
that have been removed and stockpiled. Inoculating plants ensures that “nitrogen-fixing”
plants form an effective partnership to fix nitrogen. Therefore, use of nitrogen-fixing plants
can be an important part of accelerating rehabilitation of degraded land.
Two genera of nitrogen-fixing bacteria that are important in revegetation are Rhizobium and
Frankia. Rhizobium grow with some members of the legume family (Figure 10-39A and B),
and plants of the elm family. They form nodules on the roots and fix nitrogen for the plant.
Frankia are a different kind of bacteria. Frankia partner with non-leguminous plants, such as
casuarinas, alders, bitterbrush, and buffaloberry (Figure 10-39C and D), and over 200 different
plant species, distributed over eight families. The species affected by Frankia are called
“actinorhizal” plants (Table 10-11).
A
C
B
D
Figure 10-39 | Nitrogen fixing plants
Nitrogen-fixing bacteria include Rhizobium that
forms relationships with plants in the legume
family including lupines (A), and clovers (B)
and Frankia that forms relationships with other
non-leguminous plants such as snowbrush
ceanothus (C), and mountain-avens (D) . Photos
A, C, & D by Tara Luna.
Inset 10-9 | Example of contract specifications for purchasing mycorrhizal inoculum
Purchase of Mycorrhizal Inoculum
The mycorrhizal inoculum must have a Statement of Claims that certifies
the (1) date inoculum was produced, (2) mycorrhizal fungi species present
in the inoculum, (3) number of propagules per pound of product, and (4)
the type and grade of carrier.
Product Specifications
Date of inoculum application will be within one year of production date.
The storage, transportation and application temperatures of the mycorrhizae
shall not exceed 90 degrees F. Inoculum must consist of at least 5
species of (choose endomycorrhizal, ectomycorrhizal or a combination
of endo and ectomycorrhizal) fungi with no one species making up more
than 25 percent of the propagules.
The inoculum will contain these species: _________________.
The inoculum will contain __________ live propagules per pound
(Typical rates for endomycorrhizal inoculums average around 60,000 to
100,000 propagules per pound and 110,000,000 propagules per pound
in ectomycorrhizal inoculums.)
(For applications to the soil surface only) Live propagules must be smaller
than 0.3mm.
(Optional) A one ounce sample will be collected from each inoculum and
sent to _______ laboratory for analysis using the ______ standardized
test to determine the number of propagules.
Application of Endomycorrhizal Inoculum to Soil Surface
Endomycorrhizal inoculum will be applied at a rate of ______________
live propagules per acre (typical rates range from 1,000,000 to 3,600,00
live propagules per acre).
Inoculum will be applied in the same operational period as seed application.
If inoculum is applied through a hydroseeder, it should be applied within
45 minutes of being mixed in the hydroseeding tank.
Application of Mycorrhizal Fungi to Planting Holes
Mycorrhizal inoculum will be applied at a rate of ______________ live
propagules per seedling.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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