NON-TECHNICAL SUMMARY: Current crop production systems depend on high levels of energy input and have negative impact on the environment. These systems lack species diversity. This project evaluates the use of forage legumes as a source of biomass for energy production, of protein-rich feed for livestock, of N for crop production, and of ground cover for soil conservation.

OBJECTIVES: Evaluation of N contribution by forage legumes; Document the advantages of perennial forage systems for reduction in soil erosion and bioremediation; Evaluate the effect of polycultures on biomass and energy production.

APPROACH: Field experiments will be conducted in diverse environments using valid experimental designs. Nitrogen contributions will be detemined for five legumes grown in rotation. Water runoff and tile drainage plots will evaluate effect of perennial legumes. Polycultures of temperate and native plants will be established and biomass yield and energy production measured.

KEYWORDS: nitrogen fixation; alfalfa; forage grasses; native grasses; cropping systems; native plants; forage legumes; fuel; botanical composition; biodiversity; landscapes; pastures; nitrogen; soil fertility; perennial legumes; soil erosion; erosion control; biomass; biofuels; energy production; bioremediation; soil conservation; forage; crop production; cover crops; desmanthus; kura clover

PROGRESS: 2006/01 TO 2006/12
Numerous alfalfa varieties with improved disease resistance have been released since 1940. In environments such as Wisconsin and Ohio with significant presence of disease, varieties marketed in the 1990's with multiple pest resistance had a yield and persistence advantage over varieties marketed in the 1940's and 1950's. However, in environments without disease stress such as Minnesota and Iowa, forage yields were not affected by age of release. Forage nutritive value was similar for all varieties in all environments regardless of date of release. Native perennial legumes like Illinois bundleflower, false indigo, wild blue indigo, purple prairie clover, and wild senna have potential for use in prairie restoration and grain and forage production if successfully established. We evaluated the impact of seeding rate (14 to 538 pure live seed/square meter) on establishment of these legumes. Seeding year populations of all legumes increased linearly as seeding rate increased. Second-year biomass yield of legumes ranged from 1.1 Mg/ha for purple prairie clover to 5.6 Mg/ha for Illinois bundleflower but yield response to seeding rate was limited above a seeding rate of 300 seeds/square meter. In related research, we showed that significant diversity existed in biomass yield, leaf concentration and leaf quality of 21 accessions of false indigo collected in the Midwest. False indigo has potential as a biomass crop. Corn silage is a major source of nutrients in ruminant rations. We evaluated the effect of hybrid selection and N fertilization on corn silage yield and forage quality. Increasing N fertilizer rates from 0 to 200 kg/ha increased corn grain, stover, whole plant yield, and milk yield. The forage yield and quality responses to N fertilizer rates were similar for all hybrids. Brown midrib hybrids had low lignin levels and higher fiber digestibility than conventional hybrids but lower grain and stover yields. Hybrids marketed as having extra leaves had yield and quality similar to conventional varieties. Predicted milk yield/ha was similar for all hybrids.

IMPACT: 2006/01 TO 2006/12
This research provides information on efficient production of alfalfa and corn silage that are economically important components of the diet of ruminant animals. Enhanced use of perennial legumes like false indigo and alfalfa will enhance environmental quality of landscapes by providing ecosystem services.

PUBLICATIONS (not previously reported): 2006/01 TO 2006/12
1. Grossman, J.M., Sheaffer, C.C., Wyse, D., Bucciarelli, B., Vance, C., Graham, P.H. 2006. An assessment of nodulation and nitrogen fixation in inoculated Inga oerstediana, a nitrogen-fixing tree shading organic grown in Chiapas, Mexico. Soil Biology and Biochemistry 38:769-784.
2. Lamb, J.F.S., Sheaffer, C.C., Rhodes, L.H., Sulc, R.M., Undersander, D.J., and Brummer, E. C. 2006. Five decades of alfalfa cultivar improvement: impact on forage yield, persistence, and nutritive value. Crop Science 46:902-909.
3. Sheaffer, C.C., Halgerson, J.L., and Jung, H.G. 2006. Hybrid and N fertilization affect corn silage yield and quality. Journal of Agronomy and Crop Science 192:1-6.
4. DeHann, L.R., Ehlke, N.J., Sheaffer, C.C., Wyse, D.L., and DeHaan, R.L. 2006. Evaluation of diversity among North American accessions of false indigo (Amorpha fruticosa L.) for forage and biomass. Genetic Resources and Crop Evolution 1573-5109.
5. Fischbach, J.A., Ehlke, N.J., Peterson, P.R., Wyse, D.L., Swanson, D.R., and Sheaffer, C.C. 2006. Seeding rate affects establishment of native perennial legumes in the upper Midwestern US. Native Plants online: Spring 2006:61-68.
6. Peterson, P.,* Undersander, D., Leep, R., Sheaffer, C., Sun, P., Velde, M., and Wagner, S. Hybrid alfalfa: Harvest management effects on yield and quality. Proc. 40th North American Alfalfa Improvement Conf. and the Trifolium Conf. Bloomington, MN, 16 July 2006.
7. Thelemann, R., Johnson, G.A., Sheaffer, C.C., Jung, H.G., Tschirner, U., Wyse, D.L., and Current, D.A. 2006. Productivity of biomass crops as influenced by landscape position. Proc. Assoc. for Adv. of Industrial Crops. San Diego, CA. 14-18 October. p. 83.

PROJECT CONTACT:
Name: Sheaffer, C. C.
Phone: 612-625-7224
Fax: 612-625-1268
Email: sheaf001@umn.edu