Grazing in a drought
Despite periodic snow and rain events this winter, much of South Dakota and Nebraska is still under serious drought conditions. And even with a normal precipitation year, it will likely take years for agricultural land to recover from 2012’s hot, dry weather. That’s why Bruce Anderson, forage specialist with the University of Nebraska in Lincoln, Neb., advises farmers to be conservative with their goals for pasture and forage growth this year.
“When spring finally arrives, all pastures will green up like normal, I hope,” he said,” but don’t let that first growth fool you. Below ground, many plants still are suffering from last year’s drought.”
Anderson says that during normal growing conditions, most pastures will lose more than half of the root density. Drought further reduces root growth, even without the burden of grazing. So, producers are coming into the 2013 growing season with severely limited plant resources.
Roots need to be able grow deep enough to reach moisture and nutrients in the soil, and that root growth directly links with plant health, spring pasture green up, and season-long pasture quality. Too heavy of grazing too early in a pasture’s drought recovery will result in poor pastures even in a normal, or above-average, precipitation year.
It’s important for producers to not underestimate the damage their pastures have incurred or how long recovery might take. Anderson advises producers to reduce stocking rates by at least 20 percent on improved pasture and up to 40 percent on rangeland, as well as to delay spring turnout for a few weeks to provide more plant growth to begin repairing injured roots. When animals are finally allowed pasture access, he recommends shorter grazing time and a longer rest between grazings. This can be achieved through managed grazing, which further improves pasture quality with balanced grazing distribution and carefully timed rotations through paddocks.
“When you do graze, always have a couple healthy leaves remaining to harvest sunlight to energize growth,” Anderson said.
Furthermore, he adds that producers would do well if they don’t plan on grazing through the entire growing season without adding other forage opportunities. Ideas include saving winter wheat or alfalfa to graze, and planting oats or summer annual grasses like sorghum, sudangrass, and millet.
“Summer annual forages can be a great resource and insurance that you have enough feed for your livestock,” Anderson said, but don’t wait. “It seems too early to be talking about these summer grasses, since we usually don’t plant them until late May or June, but if you think you might need to use these grasses to supply forage for your cattle this year, buy your seed soon.”
The reason is because the seed for these grasses is grown mostly in Kansas, Colorado, Oklahoma and Texas – states that were hit hard with the drought, too, and the seed production was greatly reduced, so supply is tight. Foxtail millet is already sold out in most areas, Anderson says, as well as sudangrass, sorghum-sudangrass hybrids, forage sorghum, and pearl millet.
Alfalfa may also be challenging to grow this year. Although alfalfa roots are designed to withstand drought, last year’s situation still managed to exhaust older dryland alfalfa stands and producers saw the effects when their alfalfa stopped growing far too early in the season. Because subsoil moisture levels have not recovered, this year’s alfalfa growth will be determined by how much rain falls during the growing season. Unless this year turns into an above-average precipitation year, it will not be enough to recover alfalfa yield.
“It takes about six inches of water getting into the soil to grow each ton of alfalfa hay,” Anderson said. “If you get real lucky, 90 percent of the rain you receive will actually end up in your soil. And most growers lose at least 20 percent of the potential yield due to losses during harvest. Putting these numbers together, it could take at least 25 inches of rain just to yield three tons of hay. That’s if all goes well.”
This means that there may be just enough alfalfa this year to graze to extend pasture, but to put up some for the winter or to sell, but yields won’t be back to normal, and there won’t be enough left over to renew the winter hay supply.
With this in mind, producers may have to get creative to get through the grazing season. Anderson suggests taking a look at oats and Italian ryegrass.
“I like oat forage,” he said. “It grows during spring when we are likely to receive rain and when moisture is used efficiently to produce forage. Oats can be grazed earlier than anything else you plant this spring. Once it gets five or six inches tall, it quickly can shoot up to a foot tall in almost no time.”
The downside is that oats is a little tricky to manage grazing on: If allowed to grow too much, which doesn’t take long, it doesn’t regrow much after grazing. Anderson advises starting grazing on oats when it is six to eight inches tall and then to keep regrowth at six to 16 inches.
Oats also requires a light stocking rate, only one animal per two acres, although stocking density can often increase as oats growth does, Anderson says.
To extend the oats grazing season, many producers mix it with Italian ryegrass, he suggests. While oats’ prime is early on, Italian ryegrass doesn’t start growing until June but will continue with high-quality grazing through the fall if the weather holds up.
Another idea that many producers may be considering to boost forage growth is fertilizing their spring pastures, alfalfa stands, and summer annuals, but Anderson says to remember that fertilizer applications require moisture to activate.
“This spring, subsoils are dry and forecasts aren’t promising,” Anderson said. “Most pastures will produce less grass than normal unless we have a very wet season. Plus, nitrogen fertilizer is expensive. Still, we need as much extra and early pasture as we can get.”
The best option is to fertilizer spring, cool-season pastures, but the initial green-up isn’t the time to do it. Fertilizing works best if delayed until May, in order to encourage growth that can be then used to extend summer grazing. Also, unless the spring weather changes dramatically to become much wetter, Anderson suggests applying a lower-than-usual amount of nitrogen. Waiting until May will also help producers to better judge moisture conditions and whether the full amount of fertilizer is worth applying.
“If it doesn’t rain, fertilizer dollars will be wasted,” Anderson said.
All in all, although precipitation has improved over the winter, the area’s drought conditions continue to persist, and even if this year’s weather was able to rebound, pastures and forages will be slow to recover. It’s important not to overestimate how productive this year will be.
“Don’t risk long-term pasture injury for short-term feed gains,” Anderson said. “Man
-age grazing to help pastures recover from last year’s stress.”
South Dakota and Nebraska producers can learn more about how to plan for post-drought grazing through an upcoming webinar hosted by South Dakota State University and UNL. The webinar will focus on taking an inventory of the forage available and then using that to estimate the grazing potential of the pasture. It is a free, one-hour webinar starting at 9 a.m. on Wednesday, March 27.
“Now is the time to start the planning process,” said Kalyn Waters, SDSU cow/calf field specialist. “Having the right tools and knowledge to do so will make a world of difference.”
Learn more at http://bit.ly/11Pjvwl .