Interseeding Yellow-flowered Alfalfa into Crested Wheatgrass Stands for Multiple Uses and Benefits

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Commodities

• Agronomic: general hay and forage crops, grass (misc. perennial), hay
• Animals: bovine, sheep
• Animal Products: dairy

Practices

• Animal Production: feed/forage, pasture renovation, range improvement
• Crop Production: no-till
• Production Systems: holistic management, integrated crop and livestock systems

Successfully no-till interseeding yellow-flowered alfalfa into crested wheatgrass stands is dependent on good environmental conditions and management practices. Seeding date, sod suppression, and seeding rate can affect initial establishment of yellow-flowered alfalfa. However, environmental conditions will often have a greater influence on initial establishment than management practices. Interseeding alfalfa in semiarid regions is risky because of erratic precipitation, grasshoppers, and other factors. Interseeding techniques such as herbicide sod suppression and high seeding rates can be costly and may not always be successful. Interseeding techniques that are low cost will minimize financial risk if establishment is poor.

Introduction:

Crested wheatgrass stands are prevalent in the Northern Great Plains and Intermountain West. The grass is valuable for early spring grazing, stabilizing soil, and suppressing noxious weeds (Asay and Jensen 1996). However, crested wheatgrass was often planted in monocultures (Asay and Jensen 1996). Interseeding yellow-flowered alfalfa would increase forage production, forage quality, and diversity of crested wheatgrass stands in semiarid regions.

Interseeding is a method for introducing desirable plant species to a plant community using minimal or partial soil disturbance. Interseeding is desirable when the risk of erosion is high, complete seedbed preparation is not practical, and/or the goal is to modify the existing plant community (Vallentine 1980). Adequate and timely precipitation is necessary for interseeding to be successful (Rumbaugh and Thorn 1965). Reducing grass competition, proper seeding depth, and good seed-to-soil contact improve establishment (Rohweder and Albrecht 1995).

Early spring (April) is the best time to interseed alfalfa in the Northern Great Plains (Twidwell et al. 1993). However, alfalfa has also been interseeded in late summer (late August) and autumn (October-November) (Rumbaugh and Thorn 1965).

Physical and/or chemical sod suppression can be used to reduce competition from the existing vegetation when interseeding alfalfa. Physical sod suppression techniques include tillage, grazing, mowing (clipping), and burning. Historically, interseeding in semiarid regions utilized strip-tillage on wide rows to create furrows in the sod (Vallentine 1980). Chemical sod suppression techniques include broadcast or band herbicide application. Banding herbicide has been recommended for introducing legumes into desirable grass stands (Hall and Vough 2007).

Seeding rates have generally been low for interseeding alfalfa in semiarid grazing lands. Seeding rates from 1.12 to 2.24 kg Pure Live Seed (PLS) per hectare have been suggested (Rumbaugh et al. 1982). Wide rows (61 to 122 cm) increase the concentration of seed within a row when seeding rates are low.

Determine interseeding techniques that will provide the highest probability of success with the fewest resources (financial, time, and labor).