When should you plan to renovate a pasture? How long should a pasture stay productive? These are two common questions I hear from folks across the U.S. whose pastures aren't producing their former yields or forage quality, and they want to know what to do about it.
Unfortunately, these two questions miss the real point. The more pertinent question is: Why does the pasture need renovating?
Disappearance of desirable forage species, weed invasion and declining land quality are all results of management decisions. Yes, drought, flood, insects and disease all can play a role in pasture deterioration, but there are management decisions we can make to minimize their impacts.
I frequently see dramatic differences in pasture condition on adjacent properties after so-called natural disasters. How pastures respond to stress situations is largely a function of ongoing management strategies.
Failure to make a decision is a management decision. A basic principle of resource management is you always get what you manage for. The result may not be the target you hoped for, but it's the product of your management.
Many producers mistakenly believe all their problems will be solved by tearing up and reseeding a poor pasture. In reality, the new pasture quickly will revert to the previous condition unless fundamental changes are made in grazing, fertility and irrigation management.
Uncontrolled continuous grazing is one of the most common causes of pasture deterioration. In central Idaho, for instance, the predominance of low-producing Idaho fescue on many native range sites is the direct product of the grazing management imposed. Similar sites managed more appropriately will contain a wide range of species, including several native wheatgrass and needlegrass species, along with wild ryes and other palatable grasses and forbs.
There are only a few forage species that persist and produce under close continuous grazing. They vary among states and regions, but the result of uncontrolled, continuous grazing is pretty predictable. Just a moderate level of planned rotational grazing can make a dramatic difference in pasture condition.
Managing pasture fertility
Failure to manage pasture fertility is another common cause of pasture deterioration and weed invasion. This is particularly true in the eastern half of the U.S. where soil acidity provides ongoing challenges for plant survival.
Soil testing is an important tool for land management. Use it as a decision-support aid for balanced fertility management.
I've met many producers who wanted to tear up and reseed pasture when all that was really needed was better fertility management. Adequate pH and phosphorus levels are critical to the survival of many pasture species.
Where high nitrogen (N) rates were applied in the past to drive forage production, other necessary nutrients may have been added at inadequate levels. The result is loss of legumes and less-aggressive grasses from the mixture, and an increasing dependency on expensive N fertilizer. Trying to recreate a grass-legume mixture without first dealing with fundamental soil fertility issues is a waste of time and money.
Forage species differ in their rooting habits and water needs. Irrigation management that matches the needs of your pasture mixture is key to maintaining that mixture. Heavy, infrequent irrigation favors deep-rooted species. Frequent, light applications favor shallow-rooted species.
All over the West, I meet ranchers who are converting alfalfa hay fields to grazed pastures. Most aren't happy with the high percentage of alfalfa and low presence of grass in the fields.
One way to speed the conversion is to speed up irrigation frequency while reducing the amount applied each time. As long as the watering frequency is 7-10 days, alfalfa will continue to dominate. Shorten the frequency to 3-4 days and you'll encourage grass development.
Heavy weed infestation is often cited as a reason for pasture renovation. Fact is, most weeds don't invade and elbow out desirable forage species; they're invited by inappropriate grazing management, poor fertility and untimely watering. Loss of desirable species, low productivity, bare ground and erosion all come from the same management.
Before you renovate pasture, renovate your management. How often should you plan to reseed a pasture? My answer is once in your lifetime. Manage it appropriately and it will be there.
Jim Gerrish is a grazing management consultant based in May, ID, and former lead pasture researcher at the University of Missouri's Forage Systems Research Center in Linneus. Reach him at 208/876-4067, firstname.lastname@example.org, or visit http://americangrazinglands.com.