Division of Spill Prevention and Response

Breadcrumbs

Tactic TR-11: Seeding

At sites where recovery of the pre-spill tundra vegetation is not feasible, seeding may be necessary in order to establish plant cover. Seeding is used to help control soil erosion, improve the appearance of the site, provide habitat for wildlife, and promote the eventual development of a plant community similar to the original tundra.

The type of seed to use depends on the tundra type, material spilled, and goals of the seeding effort. Cultivars of native grasses are appropriate for many sites, particularly where relatively rapid establishment of plant cover is required. The most commonly used cultivars on the North Slope are ‘Gruening’ alpine bluegrass (Poa alpina), ‘Tundra’ glaucous bluegrass (Poa glauca), ‘Nortran’ tufted hairgrass (Deschampsia caespitosa), and ‘Alyeska’ polargrass (Arctagrostis latifolia). In addition, spiked trisetum (Trisetum spicatum) has been seeded at several sites. It is generally advisable to sow a mixture of at least two species, especially if conditions vary within the site. Seed of native-grass cultivars is available from Alaska commercial growers (e.g., Alaska Garden and Pet Supply in Anchorage). The Revegetation Manual for Alaska, prepared by the Plant Materials Center (Palmer), can provide information about other possible seed sources (http://dnr.alaska.gov/ag/RevegManual.pdf).

Although the commercially available grasses have been cultivated from species native to northern Alaska, these species are not dominant in undisturbed tundra communities. At sites where the establishment of more typical tundra plants is a priority, sowing seed of indigenous sedges and/or forbs may be appropriate. Indigenous seed can be collected from natural stands, often immediately adjacent to the site. Some species, primarily sedges, can be harvested using a line trimmer with a bag attachment (Grin Reaper™, Environmental Survey Consulting, Austin, TX) (Fig. 113). Other seeds, including legumes, can be collected by hand (Fig. 114). If the seed will not be sown immediately after processing, seal it in plastic bags and store frozen for future use. Little information is available about the long-term viability of seed of tundra plants, so long-term storage is not recommended. Most seeds used for revegetation purposes usually ripen in July and August, but seed collecting is still feasible in September.

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Figure 113. Collecting seed with line-trimmer

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Figure 114. Collecting sedge seed by hand

Fertilizer should be applied before seeding to provide an adequate supply of nutrients for plant establishment and initial growth (Tactic TR-8). Broadcast large amounts of seed using a cyclone spreader (Fig. 115). The small volume of seeds typically collected by hand must also be spread by hand (Fig. 116). Both methods are best done when there is a light wind (10–15 miles per hour) to help distribute the seeds. A hydroseeder can be used for very large areas. Even distribution of seed will require some practice. One useful method is to measure and mark off an area to be seeded, fill the spreader with the amount of seed appropriate for the given area, and move in a grid pattern at a steady pace over the area multiple times until the spreader is empty.

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Figure 115. Cyclone spreader

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Figure 116. Sowing legume seeds by hand

If the surface is very flat and smooth, it may be helpful to scarify after sowing, to improve seed contact with the soil. A rake can be used to scarify small areas; for larger sites mechanized methods are more practical (e.g., drag a section of chain-link fence behind a four-wheeler).

A list of commercially available grass seed, and seed of indigenous plants that must be collected locally, is provided in Table 5 (next page). This table also recommends species and application rates for different tundra types, including those affected by salts.

Considerations and Limitations

  • A land use permit from Alaska Department of Natural Resources Division of DNR Division of Mining, Land & Water is required for collecting plants on State of Alaska lands.
  • Seeding success depends on soil conditions (nutrient availability, moisture, salinity and contaminant levels). In addition to fertilizer (Tactic TR-8), aeration (Tactic TR-5), irrigation (Tactic TR-4), and tilling (Tactic TR-6) may improve conditions for germination and establishment.
  • If the site is near the coast or saline substances were spilled, test the soil for salt before seeding (Tactic
    AM-5), to help determine what species to use.
  • Recently seeded sites may be attractive to wildlife (including birds). If this is not desirable (e.g., due to risks from residual contaminants), it may be necessary to use deterrents and/or hazing to keep wildlife away from the site.

Equipment, Materials, and Personnel

  • Necessary quantity of appropriate seed, purchased from a commercial supplier or collected from natural stands.
  • Scale - for weighing out seed for each area of site.
  • Containers – for weighing seed.
  • Cyclone spreaders (1 worker per spreader) – to broadcast seed.
  • Vehicle approved for tundra travel (1 operator) – to pull cyclone spreader for larger sites.
  • Vehicle approved for tundra travel (1 operator) and chain-link fence – to scarify surface at larger sites.
  • Line trimmer with collecting bag (1 operator) – for collecting seed of tundra plants).
  • Pruning shears (1 worker) – if needed for collecting seed of tundra plants.
  • Rakes (1 worker per rake) – to scarify surface after seeding.
  • Paper and cloth bags – for collecting seed of tundra plants.

Table 5. Examples of plant species and seeding rates used for North Slope Tundra Revegetation

Site Type

Commercially Available
Grass Seed

Locally Collected
Indigenous Seed

Notes

Recommended Species

Application Rate
(lbs/acre)

Recommended Species

Application Rate
(lbs/acre)

Wet

Arctagrostis latifolia (Alyeska polargrass)

Deschampsia caespitosa (Nortran tufted
hairgrass)

10–20

Eriophorum angustifolium (tall cottongrass)

Eriophorum scheuchzeri (white cottongrass)

Carex aquatilis

Dupontia fisheri

5

C. saxatilis and C. membranacea are also suitable, as well as other Carex species adapted to wet conditions

Moist

Arctagrostis latifolia (Alyeska polargrass)

Deschampsia caespitosa (Nortran tufted
hairgrass)

Poa glauca (Tundra glaucous bluegrass)

P. alpina (Gruening alpine bluegrass)

20–40

Eriophorum angustifolium

Carex aquatilis

5–10

C. bigelowii may also be used, as well as other Carex species adapted to moist conditions

Dry

Poa glauca (Tundra glaucous bluegrass)

P. alpina (Gruening alpine bluegrass)

Trisetum spicatum (spiked trisetum)

20–40

Legumes (e.g., Astragalus alpinus, Oxytropis viscida)

Artemisia arctica

Leymus mollis (dunegrass)

5–10

--

Salt-affected

Puccinellia borealis (arctic alkaligrass)

10–20

Dupontia fisheri

Eriophorum angustifolium

Puccinellia angustata (narrow alkaligrass)

Leymus mollis (dunegrass)

5–10

D. fisheri for moist-wet sites only


Updated: 12/20/2010