Roadside Revegetation

IMPLEMENTATION GUIDES
Fertilizer Incorporation – It is important that nutrients that are deficient and have low mobility
be incorporated into the soil prior to sowing or planting. Incorporation is possible on gentle
slopes, but becomes very difficult with increasing slope gradients because of equipment
limitations. On sites where fertilizers containing immobile nutrients cannot be incorporated,
an alternative is to create roughened soil surfaces (see Section 10.1.2, Tillage) prior to fertilizer
application. Broadcast fertilizers will accumulate in the depressions of the surface. As soil
gradually moves into the depressions over time (through water erosion or surface ravel), the
broadcast fertilizers will become covered with soil. When this happens, immobile nutrients
are accessible by roots and nutrient uptake is possible. Surface roughening also reduces the
potential for fertilizers to move off-slope through erosion.
Some agricultural spreaders, called fertilizer banders or injectors, are designed to place fertilizer,
or other soil amendments including mycorrhizae, at varying depths in the soil. Usually this
equipment has a ripping shank or tine that loosens the soil, followed by a tube that drops
the fertilizer, and coulters or rollers that close up the furrow. As the bander is pulled through
the soil, a line, or band, of fertilizer is created. Sowing and banding are often combined in
one piece of equipment and applied at the same time. Fertilizer banders were developed
for agricultural use and are limited by rock content and slope gradients. However, there are
injectors that have been develop for wildland conditions (St. John 1995).
The most common approach to incorporating fertilizer is accomplished in two operations,
broadcasting fertilizer on the soil surface and tilling it into the soil. Hydroseeders and broadcast
fertilizer spreaders, as discussed above, are means of applying the fertilizer evenly over the
site, then the fertilizer is tilled into the soil using equipment outlined in Section 10.1.2, Tillage.
10.1.2 TILLAGE
Introduction
Tillage is defined in this section as any mechanical action applied to the soil for the purposes
of long-term control of soil erosion and reestablishment of native plant communities. Tillage
equipment was developed for agricultural soils and has limited applicability for steep, rocky
sites typically encountered in wildland revegetation. This section will discuss the agricultural
equipment that can be used for wildland revegetation as well as equipment specifically
developed for these extreme conditions.
There are several reasons to use tillage in a revegetation project, including to:
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Shatter compacted soils
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Incorporate soil amendments
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Roughen soil surfaces
These objectives often overlap. For example, incorporating organic matter also loosens
compacted soils and roughens soil surfaces. Identifying the objectives for the project will
lead to selecting and effectively using the appropriate equipment to achieve the desired soil
conditions (Table 10-3).
Shatter Compacted Soils
One of the primary purposes for tilling is to loosen compacted soils. When performed correctly,
tillage can increase porosity in the rooting zone, increase infiltration rates, and increase surface
roughness. For revegetation work associated with road construction and road obliteration,
tillage to break up deep compaction is important for reestablishing plant communities.
Shattering compaction at depths of at least 2 feet is essential for the healthy growth of most
perennial plant species. Without this measure, it will take many decades for deep compaction
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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