Producers learn about rehabilitation efforts in flooded areas during Nebraska Grazing Conference
for The Fence Post
The 19th Annual Nebraska Grazing Conference kicked off with an update from Daren Redfearn, an agronomist with the University of Nebraska, about how farmers and ranchers in the eastern part of the state are coping with the damage from spring flooding.
The conditions prior to the above average rainfall contributed to the widespread devastation. “The ground was frozen, and there was no place for that much rainfall to go,” Redfearn said. “So, it went down the rivers and streams, which were still iced over from winter weather.” The volume of water broke off chunks of ice, which caused significant damage downstream. The amount of water and the speed it traveled also carried away a volume of sand, which left a lot of areas with anywhere from several inches to several feet of sand deposits. “It was overwhelming for many people,” he said.
The magnitude of the catastrophe will be felt by many producers for some time, Redfearn said. Producers were dealing with soil erosion and sand deposits this spring during a period when very few perennial plants had even broken dormancy. “The amount of sand remaining after the water receded was not expected. The amount deposited in many areas prevented removal to enhance forage and pasture production and slowed recovery,” Redfearn said.
With no programs or management guidelines in place to deal with a catastrophe like this, Redfearn said the university and government entities have worked together to try and develop ways for producers to bring this land back into production. Some of their goals have involved ways to manage sediment, stabilize sand deposits and add organic matter back into the soil to bring the land back into production.
Determing sediment depth was the first step. If the sediment is less than 2 inches deep, which is considered a shallow deposit, it has a lower impact on perennial pastures and requires only light tillage or spreading to prevent the soil from crusting over. Looking at some of these pastures, Redfearn said by the end of June, some of the grasses in these areas had already started to reemerge through the shallower deposits producing new shoots and tillers.
Moderate deposits of 2 to 8 inches deep are also considered to have minimal or low impact on perennial pastures and require only light tillage and spreading, but more rehabilitation may be required for the plants to reemerge. “Deeper sediment can suffocate plants and result in substantial stand loss. Many pastures had sediment deposits greater than 2 inches. In these cases, mechanical removal is preferred to reduce forage loss and reduce the need for reseeding,” the agronomist said.
Established pastures with more than 8 inches of heavy deposits may need to have the sediment removed or spread, and a revegetation process established on new sand deposits. Redfearn said in one area with heavy deposits, the river channel moved half a mile. “Those areas will require a lot of rehabilitation,” he said.
In heavy sediment areas, during years one and two, it is important to get the sand deposits stabilized and improve the organic soil matter. Redfearn said these areas may benefit from some annual forages like oats and other cool season plants to help with that process. By the third year, producers may want to consider planting some perennial grasses that can adapt to sandy soils. He mentioned some cool-season perennial species like smooth bromegrass or intermediate wheatgrass, as well as some warm-season species like sand bluestem, sand lovegrass, prairie sandreed, little bluestem, switchgrass and Indiangrass.
Flood events are complex, Redfearn said, and the degree and duration of the flooding, the forage species present, stand age and health, plant health and vigor, fertility level, temperature, and stage of plant development during flooding can all impact recovery.
Floods that occur in the spring are considered an advantage because perennial forages that were dormant or semi-dormant have a better chance of withstanding a flood without serious damage, Redfearn said. “Forage response to flooding is based mostly on observations because there is limited research,” he noted. But, from what they have seen, Redfearn said perennials seem to handle flooding better than annuals, and grasses handle flooding better than legumes.
“My take home message is this — pasture and forage recovery takes patience. That is the first step of recovery,” Redfearn said to producers. “Most perennial forages are resilient, and recovery depends upon the survival and growth of existing plants. As humans, we always feel like we need to do something to help Mother Nature along, but sometimes there isn’t much we can do.”
For more information about livestock, pasture and forage management after flooding, Redfearn said resources can be found at flood.unl.edu. ❖
— Clark is a freelance livestock journalist from western Nebraska. She can be reached by email at firstname.lastname@example.org.