Bunchgrass boost: Seed-amendment technology aiding rangeland perennials

Rangeland ecologist Chad Boyd, shown in southeastern Oregon collecting data on sagebrush abundance, has been working on seed-amendment technology to benefit perennial bunchgrass.

Capital Press

Researchers like Chad Boyd aim to give bunchgrass seed a boost.

Perennial bunchgrasses have big root systems that help them survive long-term amid the unpredictable precipitation levels and widely varying temperatures that characterize much of southeastern Oregon and southwestern Idaho.

But bunchgrass seeds aren’t correspondingly big and strong. Boyd, USDA Agricultural Research Service rangeland ecologist in Burns, Ore., and other researchers are making progress in developing ways to give these seeds a better chance to survive temperature extremes and wide year-to-year swings in precipitation amid increased competition from non-native annual grasses.

“We need to establish perennials quickly,” he said. “Survival is their strength, but way back, perennials had that time to establish.”

Smallish bunchgrass seeds and seedlings, if they survive extreme temperatures and hard-won moisture uptake in starting to establish themselves, now often face stiff competition from non-native annuals like cheatgrass — which puts a development time crunch on seed-stage perennials by germinating seed, emerging and producing new seed as an adult in a single year.

Enter seed-amendment technology, which basically means adding something to a bunchgrass seed to boost its chances of survival. The amendment could be placed on, against or next to the seed.

Seed-amendment examples, Boyd said, include a chemical coating applied directly to help delay germination until freeze risk passes, a pod that protects seeds therein from herbicide — put down at the same time to stop an unwanted emerging annual in its tracks - time-delay coating, and agglomeration.

Time-delay coating, used for seeds planted in a tight group, aims to cover different potential germination and freeze periods, he said. Agglomeration, another approach to increasing survival percentages, amounts to gluing together selected seeds to provide a strength-in-numbers advantage as they work through challenges such as trying to emerge through tough clay soil.

“We have seen some successes with some of the seed-amendment technologies at what I would call field-plot scale,” Boyd said. “The focus now is to continue to refine those technologies and also try to scale up.”

To work in more vast settings and on a wider scale, seeds, seed groupings and amendments will have to perform amid the varying elevations, aspects and soils found in the sagebrush steppe landscape.

“We’ve got a variety of environmental conditions we are trying to make seeds successful in,” Boyd said. “They are going to have to overcome multiple barriers to establish.”

The region’s typically wide year-to-year swings in precipitation and its tendency toward extreme hot and cold prompt scientists to steer clear of developing restoration technologies and strategies based on long-term averages. Precipitation totals, for example, fall within 10 percent of the long-term average roughly one year out of three or four, he said.

Researchers select and amend perennial seeds to increase the likelihood that more make it through tough conditions and develop into the durable stature that characterizes them in mature-plant form.

Boyd said mature bunch grasses can survive a decade or longer. He estimated 70 percent of a mature Bluebunch wheatgrass plant is underground in the form of a huge root system.

“Survival is their strength,” he said.

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