Extension Specialist Recommends Management Options for Flooded Pastures

Brookings, South Dakota (October 6, 2010)--Flooded pastures have been a major problem for some grass managers and cattlemen this summer.

Record-breaking precipitation in the state has kept many pastures, especially those along creeks and rivers, underwater for the better part of the summer. South Dakota Cooperative Extension Range Livestock Production Specialist Eric Mousel said now is a good time for producers to consider the impact all this rain has had on pasture.

"As floodwaters recede, areas saturated with water for extended periods of time likely are devoid of any vegetation, and most of the grasses in these areas were probably not adapted to be submerged for extended periods of time," said Mousel. "This situation has left many managers wondering if the grass will grow back, and it most likely will. Many of the grass species in these areas likely did not die, but rather went dormant when they were submerged for an extended period of time."

Mousel said most of the grass will grow back. Some will return this fall, and the remainder will bounce back next spring. During this time of re-growth, he said there are some considerations managers should consider.

"The stands of grass that grow back this fall and early next spring are not going to be as vigorous as they were before flooding," Mousel said. "Therefore grazing should be kept to a minimum until the stand has a chance to really recover and get going."

Another consideration is weed growth. Mousel said that large flushes of unwanted weeds will likely develop as flooded stands start to regenerate.

"The biggest species to watch is Canadian thistle, as many flooded areas will likely see heavy infestations of Canadian thistle both this fall and next spring," Mousel said. Miner County Extension Livestock Educator Jim Krantz said that as things dry out in October, producers should consider their herbicide options in combating weed stands that bounce back after the water is gone.

"In most places where pasture flooding was a major problem, managers should be prepared to deal with the expected weed problems and to treat many of these weeds this fall with a herbicide application," said Krantz. "Many of the weed species expected to cause problems in these areas are going to be very susceptible to herbicides in the fall." Krantz added that for many producers the soil is still too saturated to get spray equipment in these areas to apply any treatments. Therefore, many managers may just have to wait until next spring to apply any herbicides.

"In the fall, herbicide applications will be effective up to the first killing frost of the season," Krantz said. "Both fall and spring applications of Milestone or Tordon are very effective against Canada thistle while 2,4-D will handle most non-noxious broadleaf species." Krantz reminds producers to follow label instructions that prohibit applying these products over standing water.

Both Krantz and Mousel can help pasture managers and livestock producers develop management plans for their operations. Call Krantz at 605-772-4661, or Mousel at 605-688-5455. Or visit or call your county Extension office for information on managing pasture resources.