Pasture Recovery: Grazing management vital for plants
Whether or not the drought is over, how ranchers manage their pastures this summer is critical to long-term sustainability of the range. University of Nebraska Range and Forage Specialist Jerry Volesky discussed pasture and grazing management during drought through a recent University webinar.
“Carryover grass from 2011 supported fair stocking rates in 2012,” Volesky said, “but we will not have that much carryover grass from 2012 to 2013, because most grass was grazed heavily due to the drought.”
Although forecasters are already predicting a drier than normal year for 2013, Volesky said time will tell how much precipitation actually comes.
For warm-season grasses, precipitation in May, June and the first part of July has the most impact on grass production. In those pastures with predominantly cool-season grasses, precipitation in April and May is more important.
“Rangelands can appear quite resilient after a drought,” he said, “but if you look more closely, there can be unseen impacts.”
Grasses and weeds
“Most grasses are perennials, so they can recover and bounce back,” he added.
Three to four inches of moisture in the form of slow rains can do a lot to replenish soil moisture in sandy soils. In heavier soils, it will take more moisture, he said.
When plants go through a drought, the belowground growth is similar to the above ground growth. Volesky said if growth is stunned from the drought, at the beginning of the growing season, there may be fewer reproductive tillers or seed heads that form. This decrease may prevent the plants from reproducing to the extent they normally would.
“There may be a reduced formation of new buds that will produce future year’s tillers,” he said.
If the plants run out of water, they will mature earlier, causing a reduction in nutritional value. They may also go dormant sooner in an effort to survive the drought.
Most ranchers will notice big increases in weedy species of vegetation in pastures following a drought.
Volesky said most of these species are annual weeds that are opportunists. They show up during a drought and take away soil moisture. Typically, these species are not very palatable for grazing, he noted.
Volesky’s advice to ranchers is to remember that combining drought and grazing stress will reduce herbage production potential in the subsequent years.
“It is important to alternate the time of grazing in pastures each year,” he said. “It is very stressful on plants if they are grazed during their rapid growth phase.”
Within reason, Volesky said the grazing impact on dormant grasses is minimal because the above ground growth is dormant. However, those plants can also be injured if the pasture is too heavily over-grazed.
Pastures that were grazed from late May to early-July in 2012 should receive deferment priority in 2013 to allow them some recovery time, Volesky said.
“Try to balance the forage supply with the number of animals grazed,” he added.
Producers should evaluate their 2012 grazing records and put emphasis on time of grazing, stocking rate and the amount of residual herbage available. He also recommended rotating pastures and grazing them only once between turnout and a killing frost.
“The greatest number of cow days per acre will be obtained when pastures are not grazed until plants have completed most of their growth for the year,” he continued.
Producers should consider delaying turnout at least two to three weeks this year, which will allow plants to accumulate at least two to three more leaves and begin recovery, he said.
Ranchers may also want to consider reducing stocking rates.
Written drought plans
If a producer hasn’t already done so, Volesky strongly encouraged them to make a written drought plan.
“After talking to some producers last year that have one, the one thing they all said was that a written drought plan makes the decisions they have to make less stressful,” he said.
Precipitation should be monitored, and critical dates established based on how much precipitation there actually is and what type of forage growth is expected.
“If the precipitation isn’t there, then the deficit should trigger management actions,” he explained. “I would also encourage producers to sit down and make a list of management actions they could use in case there is a deficit.”
Producers should also consider previous year conditions, soil moisture status, temperature, both warm and cold, carryover grass and longer term weather forecast models when establishing a drought plan.
Once established, the drought plan will require ongoing reviews because every drought is different.
“There can be subtle differences in droughts, and based on when rainfall is received, it can have different effects,” he explained. “The plan may need to be modified based on observations and learning.”
As a final thought, Volesky encouraged ranchers to use good grazing management.
“Grazing management through consecutive drought years is critical for pasture health,” he noted.