Seedster Technology for More Seed Recovery, Less Impurities and Faster Ground Speed Harvesting Camelina for Biodiesel Feedstock

Camelina seed production is expanding throughout the semi-arid portion of the wheat belt and is proposed for intercropping between rows in vineyards and nut orchards. These markets and the market need for small maneuverable harvesters for research plots and breeder blocks have created a need for an inexpensive, but efficient, camelina harvester. The Seedster has the potential for meeting the demand for a camelina harvester that is inexpensive, variable width, maneuverable, has quick seed unloading and rapid cleanout. In Phase I Native Seedsters, Inc. (NSI) tested the basic Seedster technology which consists of counter-rotating brush and combing drum. The space in-between the brush and comb creates a 'pinch-point' where seed is plucked from the plant inflorescence. The first harvest of camelina with a Seedster resulted in a product that was 50% (by weight) seed, 40% seed capsule halves and 10% stems. In commercial camelina seed production the receiving elevators allows only 4.5% tare. To improve upon the purity of Seedster harvested seed a screening device was designed and tested. This device consisted of semi-cylindrical 9/64" round-hole screen which housed a 9" auger. During the second year of the Phase I project the seed purity was improved from 50% to 97% with the addition of the screening device. Although Phase I met or exceeded 4 of the 5 Performance Goals, the seed recovery efficiency was still not high enough to be competitive. In Phase I, the 40" Test-Bed Seedster capture only 59% of the total seed from stands yielding 1,100 lbs/acre and 70% of the seed in stands yielding 550 lbs/acre. The seed loss was attributed to a) seed shatter upon initial contact with the main brush, b) seed carry over on the combing drum and c) seed that 'stalled out' in the dislodgement chamber and fell back out the pinch-point because of insufficient airflow to carry the seed all the way to the seed hopper. In the Phase I Test-Bed the majority of the airflow for transporting the dislodged seed to the seed hopper was created by the main brush, with supplemental air and direction created by the air assist brush. In Phase I this airflow was insufficient to transport all of the heavy, rounded camelina seed to the seed hopper. In Phase II, a 60" Test-Bed Seedster will be assembled that is capable of configuration and reconfigurations to address these seed losses. The air-assist brush will be replaced with a tangential flow fan, positioned behind the combing drum to direct and propel all dislodged seed from the dislodgement chamber into the collection hopper, eliminating carry-over on the combing drum. The combing drum will be adjusted forward, thus making the distance between the pinch-point and the point of initial contact closer, reducing initial shatter. Various brush bristle densities and various combing drum surfaces (greater static friction) will be tested for maximizing seed dislodgement. An 8/64" round-hole screen will be tested in the screening device to try to improve seed purity to 99%. If the Phase II Performance Goals are met the Seedster will be a viable camelina seed harvest alternative for many farmers and researchers.