U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Plant Science Research: St. Paul, MN
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area St. Paul, Minnesota Plant Science Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Lamb, Joannitem
                                            SHEAFFER, CRAIG - UNIV OF MINNESOTAitem
                                            Samac, Deborah

                                                         - *Debby*
  Submitted to: Agronomy Journal
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 11/4/2002
                                    Publication  Date: 6/1/2003
                                    Citation: LAMB, J.F., SHEAFFER, C.C., SAMAC, D.A. 2003. POPULATION DENSITY AND HARVEST MATURITY EFFECTS ON LEAF AND STEM YIELD IN ALFALFA. AGRONOMY JOURNAL. 95:635-641.Interpretive Summary: Biomass fuels are being explored to replace or supplement nuclear and fossil fuels. Alfalfa is being investigated as a source of biomass for a biofuel production system where the stems are processed to produce biofuels and the leaves are sold as a source of animal feed. Previous research showed that delaying forage harvest until the alfalfa plants were starting to produce pods and decreasing the plant population to 40 percent of what is customarily used by growers and harvesting only twice per season would maximize leaf and stem yield for an alfalfa biofuel production system. However, as alfalfa matures the stem portion of the hay increases and the overall nutritive value of the forage declines. We investigated the effects of plant age and plant population number on leaf and stem nutritive value to make economic and management decisions about a biomass production system. Delaying harvest and reducing the stand density of the alfalfa plants resulted in minimal changes in leaf nutritive value and produced less digestible stems with higher protein concentration. We propose that decreasing stand density and harvesting only twice per season at a later plant age would maximize stem yield for biofuel production, increase the amount of nutritional leaf meal to be sold as an animal feed, and reduce costs in an alfalfa biofuel production system. This research will be useful to farmers who decide to manage alfalfa for biofuel uses.
                                Technical Abstract: A system has been proposed using alfalfa (Medicago sativa L.) as a biofuel feedstock where the stems would be processed to produce energy and the leaves used as a livestock feed. A management regime reducing population density, delaying harvest, and cutting two times per season to maximize leaf and stem yield would be implemented for biomass production. Our objectives were to evaluate the effects and interactions of environment, population density, and harvest maturity on leaf and stem crude protein (CP), in vitro true digestibility (IVTD), neutral detergent fiber (NDF), neutral detergent fiber digestibility (NDFD), and CP yield of alfalfa germplasms differing in fall dormancy and leaf to stem ratio. Four alfalfa germplasms established at four population densities (450, 180, 50, and 16 plants m-2) were harvested at early bud and green pod maturity stages and evaluated in three environments for leaf and stem forage quality and CP yield. Germplasms varied for leaf CP and NDF concentration, but no differences were found for leaf CP yield, IVTD, or NDFD. Stem NDF, IVTD, and NDFD were higher in the dormant than the moderately dormant germplasms. Leaf and stem CP and NDF were unaffected by population density and were consistently higher in CP and IVTD and lower in NDF when harvested at early bud compared to green pod. No discernable response patterns to harvest maturities or plant densities occurred for leaf NDFD. Stem NDFD was greater at early bud, and both stem IVTD and NDFD decreased as population density decreased. When switching to a biomass management regime, alfalfa stems may be higher in NDF and CP yield, but lower in NDFD, IVTD, and CP concentration. Alfalfa leaves would be higher in NDF, lower in CP, and the same in NDFD and CP yield.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov