Extension by Rachel MealorWritten by Rachel Mealor
By Rachel Mealor, UW Extension Rangeland Specialist
Even though there is still snow on the ground, this may be an opportune time to begin thinking about seeding projects.
What are some considerations that need to be taken into account prior to putting them into action once the snow melts? Three major ideas will be discussed throughout this article: 1) designing a seed mix, 2) seedbed preparation and 3) using the best planting methods.
Wyoming can be a difficult location to revegetate, largely due to variables out of our control, such as the cold and windy climate, variable (often low) precipitation, soils and steep terrain. However, one aspect that is in our control is the plant materials that are selected for each site. Before purchasing seeds to plant, it is essential to study the area and select plant materials that are adapted to the site and those conditions. It would not make sense to purchase seeds from a low elevation, high precipitation site, plant them on a high elevation semi-arid desert site and expect them to grow!
Success can be increased if seeds are purchased from an area similar to the location where revegetation will be taking place. Long-term success in restoring a species to a given site is dependent upon obtaining plant materials adapted to the site. So, an effective way to determine characteristics of a site is by conducting a pre-disturbance inventory. One critical component is evaluation of the plant community on a site prior to a disturbance. If this cannot be accomplished, take a look at the area surrounding the already-disturbed location and take inventory of the plant species that are found in soils that are similar to the disturbed area. It helps to document elevation, annual precipitation, timing of precipitation, growing season length, existing vegetation, soil depth and texture, and land form characteristics prior to making final decisions regarding designing the appropriate seed mix.
Selecting your seed mix depends on objectives, characteristics of the disturbed area and seed preference and availability. It may be necessary to plant a species that will establish or grow quickly, or maybe fire is a concern for the area, so a species that grows low to the ground may be in line with identified goals and objectives. Overall, it is important to define goals for the area being revegetated prior to seed selection. Seed preference and availability changes from year to year due to various drivers (i.e. the number of fires needing reclaimed). The lack of seed availability may actually determine whether or not the desired seeds can be obtained.
When selecting seeds it is best to purchase and evaluate seeds based on the pure live seed value. Pure live seed is the product of the purity (percentage of the lot by weight that consists of the crop seed) and percentage germination as performed by an official germination test. For example, a 50-pound bag of seed with 90 percent purity and 90 percent germination has a PLS percentage of 81 (0.9 x 0.9 = 0.81), and amounts to 40.5 pounds of PLS (50 x 0.81 = 40.5).
Along with this, it is important to purchase seeds from a reputable seller to be certain the seeds are good quality. Certified seeds provide a very safe and predictable source of plant materials that will be appropriate for the site. We all know that reclamation is difficult enough on many sites in Wyoming, so having quality seeds increases the chances of reclamation success.
Seedbed preparation is another important aspect of reclamation. Restoring Western Ranges and Wildlands states that proper seedbed preparation results when the seedbed is free of competition from established weeds, allows for infiltration of moisture (yet does not puddle), and is firm below seeding depth. The Natural Resources Conservation Service (NRCS) suggests that soil clods are no more than two inches in diameter and the soil should have the consistency to where a 170-pound person leaves footprints no deeper than a half inch. A good seedbed has soil with a moisture content of about 10 to 15 percent (when a weak ball can be formed from soil two to three inches below surface). Using correct tillage implements are essential in doing the job correctly. The right tool can make the difference between getting the job done and struggling to make it happen.
Lastly, correct planting methods can mean the difference between reclamation success and failure. Planting can be timed to optimize moisture for various sites. Dormant seeding, around Oct. 15 and April 15, can be an effective planting time, as soil temperatures are usually less than 40 degrees at a two-inch soil depth. Spring, summer or early fall can also be successful; however these times can be much riskier than dormant seeding.
Planting equipment should be considered in reclamation as well. Seed drills, broadcast seeders, and hydromulching are three planting methods commonly used each with benefits and drawbacks. Seeding rates are dependent on type and size of seeds, seeding techniques, soil type and moisture. Restoring Western Ranges and Wildlands generally recommends a total of eight to 16 pounds per acre for seeding native grass and forb mixtures, with higher amounts for difficult or low-productivity sites and when broadcast seeding. The NRCS suggest 20 pure-live-seeds per square foot for most species, and double that rate when broadcasting seeding on difficult sites.
As the last few months of winter pass, begin considering the various aspects to ensure a more successful re-establishment of planted species. Evaluating the aspects of seed mix design, seedbed preparation and planting methods will likely in the success of the reclamation or restoration project.