Cover crop know-how

Cover crop research is gaining ground in the Northern Plains. North Dakota State University is conducting several studies, including the following:

Cover crops in sugarbeets. Can cover crops be integrated into sugarbeet rotations to reduce wind erosion? Will cover crops or strip tillage protect sugarbeet seedlings from wind damage? Those two questions were the subject of a 2009 study at three locations in the Red River Valley on loam and silty clay-loam soils that varied from highly susceptible to moderately susceptible to wind erosion.

Both fall and spring cover crops were established, and fall and spring strip tillage was done. Researchers found that a spring-seeded barley cover crop improved seedling emergence and final sugarbeet stand; cover crops of fall-seeded rye and barley, and rye and field peas were also effective. However, spring strip tillage lowered final sugarbeet stand and root tonnage as a result of the poor seedbed. These results confirm recommendations that strip tillage be performed in the fall in the Red River Valley and in other high-clay and/or poorly drained soils, says Laura Overstreet, NDSU cover crop specialist.

Key Points

• Local universities and USDA are ramping up cover crop research.

• NDSU tests rye crimping and evaluates cover crops in sugarbeets.

• Researchers confirm that tillage boosts volunteer field pea stands.

Field pea relay cropping. Can fall flushes of volunteer field peas be used as cover crops after grain harvest? Will fall tillage foster more field pea volunteers? How much harvest loss is acceptable to achieve a good seeding rate for field pea relay cover crops?

A study on these questions was initiated at the Carrington Research Extension Center on loam soils in 2008. After field pea grain was harvested in 2008, volunteers were fostered using tillage from seed spread in the field with a combine as harvest losses. This treatment was compared to a control plot where no management was used to foster pea volunteers. The seeding rate of 6 seeds per square foot (standard harvest lost) was compared to a double rate of 12 seeds per square foot. Field pea biomass was measured in late October prior to a killing frost. Spring wheat was planted as a test crop in 2009.

Researchers found that fostering volunteer regrowth and increasing field pea seeding rate significantly increased cover crop biomass, nitrogen accumulation and wheat crop canopy cover. Enhanced cover crop production methods increased wheat yield, but did not affect protein levels.

Crimping rye varieties. Which rye varieties are most easily terminated using the roller-crimper? Does increased rye biomass production improve the effectiveness of the roller-crimper? These questions were studied in central North Dakota at the Carrington Research Extension Center on loam soils in 2008 and 2009. Researchers tested several varieties, including Dacold, Hancock, Spooner, Wheeler, Remington, Rymin, Aroostook, DRO2 and DR0207. They found rye termination using the roller-crimper was more effective for varieties with higher spring dry matter production.

This article published in the May, 2010 edition of DAKOTA FARMER.

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