1a. Objectives (from AD-416)
Our overall goal is to develop a productive, efficient, and sustainable biomass feedstock supply system using perennial grasses and legumes as a primary feedstock. This project will address critical needs for feedstock development using perennial grasses and legumes by developing innovative ways to fractionally harvest and store these feedstocks. Specific objectives are: 1) design and fabricate new harvesting mechanisms to separate the high-protein and high-fiber fractions from these crops at harvest; 2) quantify the machine's field performance using a controlled set of operating variables; 3) use this information to improve the mechanisms through re-design during the off-season; and 4) collaborate to develop on-farm storage and pretreatment systems to preserve and add value to both the high-protein and high-fiber fractions.
1b. Approach (from AD-416)
Design and fabricate equipment for field-fractionation of bioenergy crops during harvest. Test equipment on established fields of alfalfa, switchgrass, and reed canarygrass. Determine yield and quality of fractions obtained, along with power requirements and operating costs. Improve design of equipment to improve performance, reliability, and operating costs. Store harvested materials under different conditions, and determine dry matter losses and quality changes resulting from storage under these methods.
3. Progress Report
Design improvements have been made to the experimental mechanism that has been developed to fractionally harvest the leaves from the stems of perennial grasses and legumes. These design changes have included the addition of a variable-speed mechanical drive for the stripping rotor, increased ground clearance for transport, and the addition of crimping rolls to pull stems away from the cutterbar and improve machine capacity. Field evaluation has been underway. The design changes to the stripping rotor have been successful, resulting in better maintenance of rotor speed in heavy crop conditions. The addition of the crimping rolls has improved material flow off the cutterbar, but unfortunately, it has led to plugging further downstream in the process. Modifications to remedy this situation are underway. The modified machine has been evaluated in alfalfa and reed canarygrass, and will be evaluated with switchgrass later in the year. Field evaluation has been quantified by mass fraction and chemical composition in the two harvest streams, and field drying rate of the stripped stem fraction. Material has been made available to an ARS collaborator who is evaluating potential storage schemes of the high-moisture leaf fraction. Monitoring of the SCA was achieved through approximately bi-weekly telephone conversations and e-mails between ADODR and Cooperator.