Project Number: 3655-21000-056-05
Project Type: Specific Cooperative Agreement

Start Date: Sep 26, 2011
End Date: Jan 31, 2015

Objective:
1. Evaluate early- and mid-season growth regulator treatments for promoting the establishment of interseeded glyphosate-tolerant alfalfa without limiting yields of glyphosate tolerant corn.

Approach:
Objective 1: With assistance from the ARS SY, the University of Wisconsin will handle planting of glyphosate-tolerant corn at two locations in May along with fertilizer applications, pest control, and harvesting of whole-plant corn for yield in September at roughly 35% dry matter. The ARS SY will interseed glyphosate-tolerant alfalfa into corn during May and, with assistance from the University of Wisconsin, will handle pest control and measurement of alfalfa forage yields under a 3-cut harvest management during the following year. In initial studies, the University of Wisconsin will spray prohexadione-Ca in June and, with the ARS SY, assess affects on alfalfa growth during corn production and 4–6 weeks following corn harvest. Subsequent studies will examine the use of prohexadione-Ca with other foliar or seed applied growth regulators to identify promising approaches for modulating competition between the co-seeded crops and for enhancing the establishment and subsequent production of interseeded alfalfa. The ARS SY and the University of Wisconsin will jointly plan experiments, analyze data, and publish results.