|Putnam, Daniel - UNIVERSITY OF CALIFORNIA|
Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 9, 2006
Publication Date: July 9, 2006
Citation: Russelle, M.P., Martin, N.P., Putnam, D.H. 2006. Importance of forages on dairy farms, beyond their use as feed [abstract]. 2006 Joint Annual Meeting American Society of Animal Science and American Dairy Science Association, July 9-13, 2006, Minneapolis, Minnesota. Abstract No. 629. p. 449. Technical Abstract: The decline in use of perennial forages in U.S. dairy herd rations is due in part to higher yield, greater energy content, and more uniform forage quality of corn silage. Although conversion of land from rotations of perennial with annual crops to continuous annual cropping has logistical advantages, it increases the need for fertilizer nitrogen (N), pest control, and energy, and raises the risk of soil erosion, nutrient runoff, nitrate leaching, and impaired soil, water, and air quality. Perennial forages help replace soil organic matter, which improves soil aeration, water holding capacity, and nutrient supply. Thus, these forages help offset organic matter declines due to increased soybean production and replacement of solid manure with manure slurry. Additional benefits to wildlife and aesthetics may play roles on some farms, such as those near suburban development. Alfalfa offers a combination of advantages available in no other perennial forage crop. It has the capacity for high N fixation, which provides a source of free N to the farm. Fixation of new N decreases when soil N supply is high, however, so alfalfa helps buffer swings in N supply. Recent research results on a regional scale and at a feedlot remediation site demonstrate the importance of this buffering. Alfalfa’s deep roots and large N requirement help reduce nitrate leaching far better than shallow rooted legumes, and some grass forages offer the same benefit. Expanding the acreage planted to perennial forages likely will require new markets or external support. The Conservation Security Program has offered funding in targeted watersheds for practices that reduce degradation of public resources. Examples of new markets include the potential for biomass energy from alfalfa stems, with leaves as a valuable by-product, and a new facility in southern Minnesota that will be extracting four products from alfalfa and returning the residue to dairies as feed. Several improvements in perennial forages would enhance their benefits, including increased yield potential, reduced winterkill, adaptation to less frequent harvests, greater utilizable protein, greater phosphorus uptake, and reduced potassium accumulation.