Slow-growing pastures need more warmth, not added fertility, says MU forage specialist

COLUMBIA, Mo. – After a long, slow start, pasture grass just needs more time and warm weather.

Grazing paddocks that were growing 70 pounds of dry matter per acre per day the first week of May were growing at twice that rate the second week.

“A couple of warm days made the difference,” said Rob Kallenbach, University of Missouri Extension forage specialist. “We could see 150 pounds a day next week.”

Cold weather, with snow, slowed spring grass growth for grazing livestock. Kallenbach expects that to change.

But he was cautious after hearing Pat Guinan, MU climatologist, forecast temperatures dropping to lows in the 30s over the weekend.

“It’s not too late to apply nitrogen to boost hay production,” said Peter Scharf, MU soil nutrient specialist. With delayed growth, adding fertility could make more hay before grass matures. However, once grass seed heads set, leaf growth stops.

Kallenbach does not favor adding nitrogen fertilizer in spring to bump growth on grazing paddocks. That just adds forage growth at a time when cows will be trying to keep up with normal pasture growth, before it sets seed heads.

Nitrogen is for hay ground, or grazing paddocks in August to boost fall growth. That adds winter-stockpile grazing.

The MU Extension specialists were responding to regional agronomy specialists across the state on their weekly teleconference from Columbia.

“We had cows pushing snow aside to graze in May,” Kallenbach said. “I’ve seen that in January on stockpile, but I’d never seen it in May.”

Looking for the bright side, Kallenbach said the slow start in pasture growth this spring should extend the grazing season longer into what are usually the hot, dry months of summer. Summer slump should be slower in arriving, he speculated.

Craig Roberts, MU forage specialist, responded to “What happened to the clover?”

“White clover should return,” he said. “Usually it thrives following wet spells. But red clover is different. The drought hurt stands last year and no seed set.

“If 4 pounds of seed per acre was not sown on dormant pasture in late winter, there may not be any red clover.

“Even our best red clover cultivars rarely last much beyond two years. Frost seeding red clover is recommended every year until the soil seed bank is refilled.”

Wayne Flanary, regional agronomist in northwestern Missouri, asked about sowing emergency grazing for beef herds this summer.

Sudan-sorghum and pearl millet make warm-season grazing, Kallenbach said. But don’t rush to seed the summer annuals until soils warm, to 65 degrees Fahrenheit, consistently.

“That’s not just 65 degrees on a peak day,” he added.

“I’ve planted a lot of warm-season annuals,” Kallenbach said. “All of my failures have been from planting before the ground was warm. Seed planted too early produces lousy yields.

“It’s not too late too plant warm-season annual grass,” he added, “given the conditions we’ve had.”