Continuing drought, overgrazing reduce forage Forage growth is almost complete by July 1, and precipitation after that date will not relieve production shortages, a South Dakota State University specialist said.
"Research shows that season-long forage production is mostly related to precipitation received in April, May, and June," SDSU Extension Range Management specialist Roger Gates said. "About 40 percent of the season's growth has occurred by May 1, 60 percent by June 1, and 90 percent by July 1."
"Precipitation across South Dakota was below normal for a period from early April to mid-May. This exacerbates conditions resulting from 30 or more months of subnormal precipitation for nearly all of western South Dakota," Gates said. "It is likely that production potential in much of the western part of the state has already been reduced by at least 30 percent."
Long-term drought conditions result in a shift in native plant species composition from more productive to less productive. The process is accelerated by the additional impact of overgrazing.
"Producers must reduce stocking rates in response to the lower plant production resulting from drought. Native vegetation is adapted to recurring drought, but survival of even the best adapted species can be impacted by overgrazing."
Gates adds that, unlike the situation in 2002, subsoil moisture has been depleted to the extent that most growth depends entirely on current precipitation.
"The seasonal growth pattern characteristic of our most important perennial forage plants dictates that the subnormal production already experienced in this growing season will not be relieved, even if a more normal precipitation pattern is restored," Gates said.