|SHEAFFER, C - UNIV OF MINNESOTA
|PETERSON, P - UNIV OF MINNESOTA
|PUTNAM, D - UNIV OF CALIFORNIA
Submitted to: North American Alfalfa Improvement Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2002
Publication Date: 7/30/2002
Citation: SHEAFFER, C., LAMB, J.F., PETERSON, P.R., PUTNAM, D. HERBAGE AND N PRODUCTION BY NONDORMANT ALFALFAS. NORTH AMERICAN ALFALFA IMPROVEMENT CONFERENCE. 2002. ABSTRACT. P. 73.
Technical Abstract: Organic food production is a rapidly growing segment of Midwestern agriculture. It depends on non-synthetic sources of N such as animal manures and legumes used as green manures. For many organic producers without livestock, traditional cropping systems that include production of legumes for multiple years are not practical. An alternative approach is to manage the forage legume as an annual crop with the legume winterkilling during the winter. Field experiments were conducted at Rosemount in southeast and at Lamberton in southwest Minnesota. We spring-seeded commercial and experimental nondormant alfalfas, a dormant alfalfa, Marathon red clover, berseem clover, and annual medics and measured herbage dry matter yield 1 or 2 times by early September. In mid-October, herbage, root, and crown dry matter and N yield were measured. Nondormant alfalfas had similar fall N yield (104-113 kg ha-1) that exceeded the N yield of dormant alfalfa (98 kg ha-1), red clover (90 kg ha-1), or berseem clover (20-45 kg ha-1). "Paraggio" barrel medic had a fall N yield of 38 kg ha-1 at Rosemount but none at Lamberton. The other annual medics had no fall herbage regrowth or root and crown yield. Summer herbage dry matter yield of all alfalfas was similar and consistently exceeded the herbage yield of most annual medics and Berseem clovers. Winter survival of nondormant alfalfa vareites varied but following the mild winter of 2001-2002 all survived. The forage and N production of commercial nondormant alfalfas could be used as annual green manure legumes. Berseem clover and annual medic varieties provided summer forage production but less fall N for incorporation compared to the nondormant alfalfas.