Revegetation Guidelines for Western Montana - Global Restoration ...

Testing chemical properties of the soil 5 can be helpful in directing or confirming species
selection and in suggesting any soil amendments. Further, testing indicates the suitability of
the soil for plant survival and growth. Challenging revegetation projects should test area soil
for:
a. pH – optimum range is 6.5 to 7.5; seeded species adapted to highly acidic (pH < 6)
or highly alkaline (pH > 8.4) soils should be used instead of attempting to amend
the soil with additions of sulfur, peat, lime, or fertilizer. Grasses, grasslike species,
forbs, and shrubs adapted to saline-alkaline soils are provided in Tables 2, 3, and 4.
b. Electrical conductivity – a measure of soil salinity; optimum range is 0 to 2
mmhos / cm soluble salts.
c. Sodium adsorption ratio – proportion of sodium ions compared to the
concentration of calcium plus magnesium ions in the saturation paste; optimum is <
6; when SAR rises above 12, serious physical soil problems arise and plants have
difficulty absorbing water.
d. Organic matter – percent organic material and humus in the soil; optimum is >
3% organic matter. Organic matter increases soil porosity, infiltration, water-holding
capacity, nutrient reserves, and improves soil structure. The addition of organic
matter, such as compost, can increase soil microorganism development and, in turn,
enhance seeded species establishment.
Figure 2. Soil textural triangle illustrating the range
in composition of sand, silt, and clay for each soil
textural class. The dotted line depicts a loam soil
that has 45% sand, 35% silt and 20% clay content.
Precipitation, soil moisture, temperature, and elevation of the site
Seeded species should be adapted to the precipitation and moisture level of the soil.
Temperature zone and elevation of the site should also be addressed - see Table 5 for
recommended grass species by western Montana zone.
Wildland seed, or seeds collected from the local landscape, are locally adapted and can have
excellent establishment and long-term resiliency. But large quantities must be collected to
5 For a listing of soil testing laboratories, request the following publication from your local county Extension office:
J.S. Jacobsen and S. Lorbeer. 1998. Soil, plant and water analytical laboratories for Montana agriculture.
Extension Service Bulletin EB 150. Montana State Univ. Bozeman.
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