Application of plant seed to slopes by ground equipment or manually.
Purpose: Ground seeding is done in localized areas of high burn intensity where reestablishing plant cover quickly is essential, such as riparian areas, above lakes and reservoirs, or highly productive forest land. Annual or perennial grasses, usually non-native pasture grasses or cereal grains, and non-native leguminous forbs, are typically used. Ground seeding assures more even seed application than aerial seeding and sometimes includes treatments to cover the seed, which enhances germination. Seed is applied from all-terrain vehicles or by hand.
Relative Effectiveness: Excellent-9% Good-82% Fair-9% Poor-0% (Replies = 11). Ground seeding was judged "good" in effectiveness by most interviewees. As with aerial seeding, the post-fire weather pattern frequently determines the effectiveness of cover production by seeded grass. High winds may blow seed off site. First rains can wash ash and seed from the hillslope, or they may be gentle enough to stimulate germination. Use of a rangeland drill, raking, or mulch to cover seed increases success. One forest used cattle to trample seed into the ground and break up a hydrophobic layer. Non-native species, especially perennial grasses, grow well, sometimes too well, and provide persistent cover. Cereal grains disappear in a few years.
Implementation and Environmental Factors: Timing of seed application is essential to success; optimum timing depends on local weather pattern. The seed mix must be adapted to the soil type. Awned or very light seeds spread more easily if rice hulls (or similar material) are included in the mix. Grass growth is best on lower angle slopes (less likely to wash away). Protection from cattle grazing the first year is considered by some to be the biggest factor in success; protection for 2 or 3 years is good. Elk may have a negative effect on seeded grasses as well.
Factors to consider when prescribing seed include:
|Slope and aspect|
|Timing of applications|
|Need for structural aids (mulch, site preparation, etc.)|
|Management direction for the area|
|Runoff characteristics of the area|
Calculating Seed Rates Based on Pure Live Seed per Square Foot
Seeding rates for grasses are generally expressed in pounds per acres. However, if a seeding prescription is based on pounds per acre instead of Pure Live Seed (PLS) per square foot, excess costs can be experienced. Generally, to achieve efficient erosion control, seeding rates should be in the range of 30 to 60 PLS per square foot.
Seeding rates can be calculated if you know the following:
|The total number of seeds per pounds|
|The percentage of each pound that is PLS|
|How many acres needing treatment|
|The target PLS per square foot rate|
Seed one acre with Standard Crested wheatgrass which has 175,000 seeds per pound and is 76% PLS to get a result of 40 PLS per square foot.
(1 acre)*(43,560 ft2/acre)*(40)=1.742,000 PLS
Seed one acre with three species at different rates to obtain a coverage of 30 PLS/ft2
Species 1 = 175,000 seeds/lb; 76% PLS; 30% of mix
Species 2 = 645,000 seeds/lb; 71% PLS; 40% of mix
Species 3 = 227,000 seeds/lb; 87% PLS; 30% of mix
(1 acre)*(43,560 ft2/acre)*(30)=1,306,800 PLS
Species 1: (1,306,800)*(0.30)=392,040 PLS
(392,040)/(133,000) = 2.95 lb
Species 2: (1,306,800)*(0.40)=522,720 PLS
(522,720)/;(457,950) = 1.14 lb
Species 3: (1,306,800)*(0.30)=392,040 PLS
(392,040)/(197,490) = 1.99 lb
Total Mix: 6.087 lb/acre