R.L. Hamblen, Bugwood.org
Often people think a pasture must be totally renovated or made "new" to be productive, when actually they can use restoration techniques. This article addresses the differences between the two management approaches to ultimately have good productive pastures for animals.
Restoration: Soil Building and Animal Management
Many pastures are just in need of some "restoration." Examples of restoration include fertilization, liming, weed control and improving the movement of animals through the pasture to control grass height. Often, "restoration" can be applied and bring pastures back to productivity.
Soil testing is a tool that is underutilized by many pasture managers. If fertility and pH is low and the need for pasture production is high due to high stocking rates, take a soil test. If pastures are under-stocked and there is a grass surplus, take a soil test. Testing can help us understand how the soil resource is performing and where to make the next soil management decision. For example, if feed supplies become tight, then the use of lime is justified to increase the utilization of manures by plants. A basic soil test kit from the Ag Analytical Lab at Penn State University is available through county extension offices across the state for $9.00 and covers about 10 acres.
I also recommend that organic matter content should be tested, along with fertility. Pasture managers can monitor the change in organic matter over time. Organic matter influences biological activity, porosity and the soil's ability to hold more nutrients. If you take a Penn State soil test, add another $5.00 to the kit and check the box on the form.
Weed management is directly tied to soil fertility. Weed problems are often present in pastures due to an overabundance or insufficient amount of soil fertility or improper pH. If grass cannot grow due to inadequate nutrients, then weeds will be more competitive than the grass. If there is an overabundance of fertility, weeds can grow very vigorously. Using herbicides in pastures is mostly justified where we need spot treatment and they should be part of an integrated approach -- not the sole answer to weed control.
Animal movement through pastures has a tremendous effect on pasture growth and weeds. For a more complete discussion of this, please refer to Dr. Jessica Williamson's article in this week's issue.
Renovation Comes with Risks and Rewards
Renovation is defined as the complete destruction of existing pasture and reestablishment of the pasture. This is best done when the pasture has been severely overgrazed and most of the grass has been lost. Usually, weed growth is dominant (i.e. 40% or less of grass in the pasture). The types of weeds are usually aggressively growing and not considered palatable by animals. An evaluation tool that can be used by managers to access the need for renovation is a Pasture Condition Score, developed by the USDA-NRCS to help assess the quality of the pasture. (See Resources)
Renovation should not be taken lightly. It is costly in terms of inputs, labor and time (including the time loss of those acres for production). The overall goal should be to rapidly establish a seeding with minimal weed competition. The following suggestions are all techniques to arrive at this goal.
Soil fertility is best done several months in advance in order to make decisions and gather inputs. If the pH is adequate, a producer could consider using no-till to establish the grass, assuming they have access to a no-till seeder. If the pH is very low (below pH 6), consider using tillage. Tillage will mix the lime throughout the soil.
Seeding in the spring can be risky as the soil temperatures are cool, allowing weeds to germinate ahead of pasture plants. Seeding techniques are very important to ensure good germination of the seed. Make the decision regarding tillage or no-tillage based on access to equipment or a custom applicator. Modern no-till seeders do an excellent job and are becoming more commonly available. If no-till is being used, kill the existing pasture with glyphosate ahead of the seeding date. Check seeding depth required by your seed mixture. Make sure the seed is being dropped into the soil, not the killed thatch layer. If using conventional tillage, make sure the seedbed is properly established. Prepare the seed bed so that it is firm. Your foot should leave an imprint on the soil surface.
The pasture plants to be seeded need to be matched to the soil type to ensure plant survival over time. Seed mixtures have gotten more diverse and can include grasses and legumes. Managers are better off researching what seed mixtures or combinations would work best for their site. New research indicates that a diverse pasture mixture (i.e. 6 species) can help with reducing weed competition rather than relying on a single monoculture.
Once your pasture is germinated and growing, newly planted pasture plants need time to develop strong roots. Grow the pasture to flowering height, mow and bale, cutting as high as possible. Allow the pasture to regrow and then allow animals to graze.
After establishment comes ongoing pasture maintenance. Restoration and renovation are two approaches to maintaining a dynamic ecosystem that is constantly changing based on factors such as weather, grass height management, and fertility. Your goal should be to maintain a robust grass ecosystem that supports healthy productive animals with quality feed.
Guide to Pasture Conditioning Scoring Website, USDA-NRCS