|Darmosarkoro, W - IOWA STATE UNIVERSITY|
|Harbur, M - IOWA STATE UNIVERSITY|
|Moore, K - IOWA STATE UNIVERSITY|
|Anderson, I - IOWA STATE UNIVERSITY|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 12, 2001
Publication Date: N/A
Interpretive Summary: For economic and efficient production of meat and dairy products producers need an inexpensive, readily available on farm source of high protein forage. Legume crops such as alfalfa have traditionally been used to provide this high protein forage. Soybeans are less expensive to establish and do not require insecticide to prevent damage from annual infestations of the potato leafhopper. In addition, soybean is a spring-seeded annual that can provide high protein forage when winter killing depletes alfalfa stands. The U.S. Department of Agriculture recently released three soybean cultivars bred for use as forage: Derry, Donegal, and Tyrone. The forage lines were superior to the grain-type lines in forage yield and produced as much as 19% more forage yield than the highest yielding grain-type line. The ability of the new forage cultivars to produce high yields of high quality forage will enable dairy farmers and livestock producers to more efficiently provide products such as milk, cheese, meat, and wool for consumers at reasonable prices. The information in this report will provide guidance to research and extension scientists in making recommendations to farmers producing forage for livestock enterprises.
Technical Abstract: Soybean, Glycine max (L.) Merr., has the potential to produce abundant herbage for forage. Recently, soybean lines have been developed specifically for use as a forage. The objective of this study was to evaluate the agronomic performance (vegetative growth and above ground biomass yield) of these soybean lines in the Western Corn Belt. In 1994, thirteen forage soybean lines and five check cultivars were studied. In 1995, in addition to these entries, one new forage line and an additional check cultivar were added. Plants were grown in 76-dm rows and samples were collecteed biweekly. By 125 d after planting (DAP), forage soybean lines yielded 5 to 19 percent more dry mass than "Sherman", which had the greatest yield among check cultivars. Forage lines were 37 to 69 perent taller than "Biloxi", the tallest check cultivar. Forage lines with the highest yield and lowest lodging scores (1=upright to 5=prostrate) were OR 14-13-2 (10.8 t ha-1 and lodging score of 1.8) and OR 13-11-2 (10.5 t ha- 1 and lodging score of 1.5), which attained heights of 1.87 and 1.95 m, respectively. The leaf area indexes (LAI) of these two forage lines were 5.5 and 5.3, respectively, which were less than that of Biloxi (7.5) and higher than that of Kenwood (4.9), two check cultivars. Forage lines initiated reproductive growth 60 to 88 dAP, whereas Sherman initiated reproductive growth 55 DAP. Forage soybeans had more stem dry mass accumulation than did grain-type soybeans. Based on agronomic performance, forage lines were superior to grain types for forage production.