Extension Education: Grazing Management after Drought
Grazing after drought will be determined largely by the amount of precipitation that is received in the current year.
As shown in figure one, the range will look pretty rough in a drought year, but the same range will rebound and actually can have surplus forage if precipitation the following year is normal or above, especially if the range had been stocked correctly.
Forage levels are determined largely by the amount of spring precipitation that is received from March through June for the current year. It is too early to tell what kind of forage production we will have this year, but by the end of May, for most locations, we should be able to predict with some certainty the amount of forage that will be grown for the year.
Most ranches can sustain one or two dry years in a row. This is especially true of operations that are grazing at a moderate level. Moderate level would mean taking half and leaving half of available forage in a normal year of precipitation.
When there is drought for three or four years in a row, the situation can become problematic. Failure to care for the land during a long-term drought may create serious consequences on pasture and rangelands for decades to come.
Overgrazing is severe, and frequent grazing during the active growth period of the plant is most harmful if done year after year. For our cool season grasses the active growth period is typically in May; for warm season grasses, it is in June. Higher elevations and the amount of snow cover will make these dates later.
Changing where livestock graze during spring growth will help to reduce the effects of overgrazing. Not grazing an area every fourth year or only grazing it every fourth year after the seed head has matured helps in preventing overgrazing.
Indicators of past overgrazing are weeds have become more prevalent and more bare ground. Weeds are more competitive because they grow earlier in the growing season, and many of them have deeper tap roots that compete with the shallower-rooted forbs and grasses. Bare ground will increase as a result of grasses and forbs succumbing to repetitive overgrazing. Grasses and forbs may come back, depending on seed or rhizome availability.
Brittle, low precipitation areas are more prone to degradation and have longer lasting negative effects than areas where there is more precipitation. It also takes more to return the low precipitation areas to their potential natural community.
Poisonous plants can become a bigger problem following drought because they may be the tallest plants, and there may not be much desirable forage for the livestock to eat. Thus, the amount of poisonous plants, as compared to grasses, during drought is higher and will have a more toxic effect on the livestock. Grass tetany is more likely following drought because of the lack of left over forage and the lush new forage, thus supplementing magnesium may be required.
Grazing livestock following drought has a lot to do with if there is any residual forage from the last year and the amount of forage grown in the current year. If there is little or no forage present, it is difficult to get any utilization out of the pasture. Selling, reducing the amount of livestock or finding somewhere else to graze will be a necessary strategy.