Extension by Mealor and Smith

Dry Times Are Here Again
By Rachel Mealor and Mike Smith, UW Extension

    Although spring has brought bright sunny skies, the accompanying lack of moisture has not been a complementary bright spot. April and May are crucial months to receive precipitation, and with the mild winter we experienced, we may be in for a very dry summer throughout much of Wyoming. This always brings to the forefront of our minds the issues that accompany below-average precipitation years. Many Wyomingites have experienced drought before, some even say it is the wet years that come as a surprise. There are aspects of an agricultural operation to take a good look at when these dry years come along. We’ll discuss a few considerations when dealing with lack of moisture during these warm days.
    Below-average precipitation levels can affect livestock producers in numerous ways. Not only does it lead to a lack of water to fill reservoirs and irrigation ditches, dry spring weather can severely limit forage production on our rangelands. For the purposes of this article, we will focus on the below-average precipitation levels during the spring that have the most impact on rangeland systems and forage production. For planning purposes, it is beneficial to have an idea about where Wyoming is, or will be, as far as precipitation goes. Probability predictions of normal, above- or below-average precipitation and temperature can be found at cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=01. Rangeland forages largely depend on spring moisture, but successfully predicting the effects of the time and amount of precipitation on vegetation varies with elevation and plant community types. The differences between lower and higher elevation locations in predicting forage yields are due to soil thawing earlier, vegetation greening up a bit sooner and more warm-season grasses being found at lower elevations.
    The probability of getting enough moisture in May or later to make up for low precipitation levels earlier in the spring is relatively low. Therefore it may be a good idea to think about forage amounts and livestock management strategies by the first of May. Precipitation amounts should inform livestock managers’ decisions of whether to maintain, decrease or increase stocking levels. So, it is probably safe to say this year we will experience dry conditions as the summer quickly approaches. What should we be thinking about?     
    There are a number of different strategies that can be used to mitigate some of the impacts of below-average precipitation on a livestock operation. A few strategies are: liquidating parts of the herd or not keeping replacement heifers, leasing or purchasing additional grazing, altering grazing strategies and water facilities (change to a rotational system and possibly hauling water), early weaning of calves, selling yearlings that have been retained, and purchasing additional winter feed. If herd liquidation is done, the addition of alternative crop or livestock enterprises can be a solution to the decrease in monetary gain from just one class of livestock.
    Because many of the rangeland plants in Wyoming are adapted to this climate, they show little long-term effects of periodic drought. However, dry conditions can easily lead to overgrazing plants due to there being less plant material or growth for that year. Keeping an eye on forage residual by managing use levels in a pasture during the critical growing period of cool-season grasses (the early boot stage) and deferment the same time the following year can assist in long-term plant health. Deferring grazing merely to recover from drought is not necessary if the grazing program provides periodic deferment during the critical growing period (as in simple rotational-deferred or short-duration grazing systems). As mentioned above, hauling water may have to be considered, especially in very dry years. If additional water can be provided to livestock and stock can get to the surrounding forage this can provide access to additional forage and decrease the chances of over-using areas closer to remaining water sources (that may have experienced pressure in the past). For summer pastures, surface pipelines can be used to provide drinking water and help move animals around to potentially utilize forage that would not normally be accessible.    
    Dry conditions can impact various aspects of the operation, from grazing capacity to irrigation water supply that can lead to a decrease in winter feed production. However, there are ways to anticipate effects of below-average precipitation. A flexible grazing strategy, altering water facilities, and planning timely actions can minimize the impacts from dry conditions. If we continue experiencing below-average precipitation in the next few years, it is best to have a drought plan that also accounts for longer-term cumulative effects. Livestock operations may also benefit from plans in which numerous strategies are taken into account.
    For more information, visit wyomingextension.org/agpubs/pubs/B1220.pdf and wyomingextension.org/agpubs/pubs/MP111_09.pdf. Contact Rachel Mealor at 307-766-4139 or rdmealor@uwyo.edu.