During this year's "Cattlemen's Roundup," coordinated by the University of Nevada Cooperative Extension, I gave a presentation on developing a drought management plan.
As current drought conditions have not improved from the winter months, I thought that I would write a series of articles that may help ranchers deal with imminent drought conditions.
For ranchers, drought can be defined as too little soil moisture to meet the needs of dominant forage species during their rapid growth windows. Drought is a natural part of climate in nearly every region on earth.
A more scientific definition for drought would be: "Drought is generally defined as a prolonged period during which annual precipitation is less than 75 percent of average."
As you can see by the U.S. Drought Monitor Map, most of northwestern Nevada is in extreme or severe drought conditions as of May 28.
The following information comes from the "Managing Drought Risk on the Ranch Planning Guide," developed by the University of Nebraska - Lincoln National Drought Mitigation Center, which is available online at: www.drought.unl.edu/ranchplan.
I would recommend that all ranchers download a copy and begin developing your drought management plan. Producers who focus on increasing flexibility and maximizing the health of resources are more likely to find solutions during drought that minimize painful decisions with limited resources. The longer you wait to make decisions, the fewer options you will have available to you.
Knowledge of basic plant physiology is needed in order to deal with drought conditions. Carbohydrates produced from photosynthesis provide energy for all plant growth and maintenance. Plant growth is reduced or delayed when green leaf area is removed, or when soil moisture limits the amount of carbohydrates that can be produced. Overgrazing and drought during the plant's rapid growth windows will reduce next year's plant growth.
Also, plants rely on stored energy to survive during dormancy, and for initial growth after dormancy. Plants must rely on stored energy for unusually long periods of time when drought-induced summer dormancy is added to winter dormancy. Early spring growth that is stopped by drought or frost will deplete the plant's energy reserves and reduce forage production potential the following year.
Understanding the interactions of livestock, plants, and precipitation is also important to managing drought risk on the ranch. Grazing management influences the effectiveness of precipitation. Plant cover and healthy root systems result in better infiltration of moisture into the soil. Overgrazing can cause drought-like conditions even with average precipitation.
The effects of drought are intensified at poorer range conditions. Rangeland in "fair" condition is often more severely affected by drought than rangeland in "good" to "excellent" condition. Range condition also influences the rate of recovery in forage production after drought.
Therefore, stocking rate and grazing system decisions are most likely to affect animal performance in the second half of the grazing season. In contrast, these decisions are most likely to affect plant vigor and herbage production potential during the first half of the next summer grazing season.
The best time to make drought-related decisions is sooner rather than later. Here are some reasons why:
1. Plant Year Precipitation - Precipitation received between last year's killing frost and this year's spring green-up results in greater yield of forage per inch of moisture than does mid- to late-summer precipitation.
If little to no precipitation falls during the dormant season, timely
- See DROUGHT, Page 24 -
destocking is necessary to avoid damaging rangeland vegetation. So if you're entering green-up and have seen no precipitation since before last year's killing frost, or if you are lacking soil moisture, it is already a good time to make changes to this year's stocking rate.
2. Critical Rain Months - Forage research shows that the most important months for precipitation are the months just prior to the rapid growth periods of your dominant plant species.
For much of the Great Plains, those critical rain months occur in spring through early summer. Rainfall that occurs after the rapid growth period of dominant plant species does not result in as much usable forage.
3. Delays in response to precipitation - Areas mapped on the U.S. Drought Monitor (http://droughtmonitor.unl.edu) as being in extreme or exceptional drought during the growing season are likely to have a one- to two-week delayed response to rainfall.
Additionally, the process of "wetting-up" very dry soils in these areas reduces the availability of rainwater to plants. Delays in plant response to precipitation should be expected when current plant-year precipitation in your immediate area is 75 percent or less of long-term average. Excessive grazing pressure during drought will further reduce or preclude yield responses to even measurable amounts of precipitation.
Even in non-drought years, herbage production rates decline as the summer grazing season progresses while forage demand increases 35 percent to 40 percent as cattle gain weight.
In average years, plants "outgrow" livestock on the front half of the season. When this does not happen in drought years, you must be ready to act quickly. Having a plan ahead of time will help you act quickly when necessary.
Following articles will provide more information on writing a drought plan to include what to do before and during drought conditions.[[In-content Ad]]
