Back to the Basics of Revegetation
by Marc Mustoe
There are many articles written about successful ways to establish plant material on disturbed sites. Several new developments, both Mechanical and Biological, have been introduced recently to help improve that establishment. Some are more successful than others, but one thing remains the same, all are dependent on the critical and most basic components of the site they are being used on. Therefore when we revegetate disturbed sites, we need to take a serious look at the basics of the situation: soil, rainfall, topography, and other key factors. After analyzing the basics, we can then put a detailed plan together. With patience for plant growth, and a little luck, we will create a successful revegetation job. However, we must always realize that mother nature will play a big role in the success or failure of the project.
When starting a revegetation project, we need to know what it is we are trying to accomplish. Too often we hurry to put something together without thinking through the long term. In many cases the objectives are simply erosion control. In others, we may need short term erosion control, with a desire to develop wildlife habitat using mostly native species. Things can get complicated in a hurry, but knowing and understanding the entire picture will help in the long run. At best, it seems like a jigsaw puzzle, but there are some important and very basic pieces to this puzzle that we must get in place in order for successful long-term revegetation to occur.
The soil must have the ability to sustain long-term plant growth, not just the quick flash of new growth that will die in drought or harsh weather. The soil must be suitable to establish and maintain a plant community over a long period. To do this, it must have a suitable Ph for the plant material seeded, have the needed nutrients, and have enough organics to retain moisture and maintain important soil organisms. Without this, no matter how good the initial plant stand is, the soil will not maintain it. Soil testing will help determine what you have and what you may need, whether that be soil organic amendments, or nutrients. Once the proper soil is in place, then the preparation of it becomes critical. Plants do not establish well on hard impacted or crusted soil. Sometimes changing the soil make up and condition is expensive, if not impossible. However, whatever we can do to make that most important medium a better place for plant establishment, the more successful the seeding will be, in turn, reducing expensive reseeding projects.
When the soil is satisfactory, then selecting the proper species to work on that soil and site becomes the next task. Once again, thinking about the long-term of the project becomes important. Each species brings its own unique capabilities, such as erosion control, forage value and aesthetic beauty. Whatever the case, decide what you need and determine if it will work on the site, given the soil, rainfall, topography and climate. Arrowleaf Balsamroot is a great Forb, but is may not be appropriate for your site. After determining which species will work, put a mix together with seeds that compliment each other. Having a seed mix that is diversified with at least five or six species, not only satisfies need, but allows tolerance for the many small microclimates that are often present.
Placing the seed is a critical part of the restoration plan. Grass seed lying on top of mulch or organic residue, or three inches deep in the ground just doesn't work. The proper seed to soil contact is important. Some sites are simple, and one application method is all it takes. Others however, are not that simple, and drill seeding may be appropriate for the flats, hydroseeding for steep slopes, and hand seeding for wetland restoration around streambanks and ponds. Seed that is on the ground and covered lightly with soil or mulch, or seed that is drill seeded to an appropriate depth, depending on species, will perform better than seed laying on top of the ground exposed to the elements. However, seed applied to the last of the spring melting snow, and allowed to settle itself into the ground as the snow melts, is also a good seeding method. Whatever the case a good prepared seed bed with proper application can make a tremendous difference.
In this industry as well as others, due to cost and workloads, we tend to do a job, go to the next and never return. We would all benefit from a return visit to the site. Although each is different, we can learn something from every job. Also, for the success of the project, follow-up can make a big difference if we notice a weed infestation that can be controlled early, or a need for additional nutrients. Simple overview can keep a major disaster from happening.
I recall watching my dad and grandpa, shortly after a new grass seeding, carefully following drill rows on their hands and knees, turning over the top bit of soil with their pocket knives in hand, looking for those anxiously awaited new seedlings. Finding none, they would say to each other, "Let's give it a few more days". From this, I came to understand the importance of patience and time with plant establishment. In most cases, barring some awful storm, a few days or weeks will make all the difference in the world. It does not mean that if in six months all you see are weeds, that the site will be fine. But in most cases, we all expect miracles to happen overnight, when we know that revegetation, especially with slow to establish natives, takes time. Many formulas exist for plant numbers per square foot or square yard. But in the long run, look at the site and think what that site, given the soil, rainfall, and other characteristics can really do. Look also at the native area around the site, then set a plant density goal. If in the first few weeks you see enough emergent new seedling to accomplish that, then follow it up, but give it time. Because in most cases time is in your favor. Helping land owners to understand this concept is sometimes very difficult, but important for them to understand.
Revegetating a disturbed site can be challenging and rewarding work. Using new technology and incorporating it with the very basics of what it takes for successful plant establishment allows for even greater success today than in the past. Maybe the key for all of us working to revegetate disturbed sites is not only just setting goals, but putting solid plans together and implementing them. Even more important, is having the understanding and patience to see the project through for its long term success. Only then have we really made a contribution to making our world a better place to live. L&W
For more information, contact Mark Mustoe, Grassland West Co., P.O. Box 489, Clarkston, WA 99403, (509)456-7712, fax (509)456-7742.
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