Master of Science / Department of Biological & Agricultural Engineering / Ajay Sharda / Moisture measurement is critical when baling alfalfa into round bales for feed. If alfalfa is too wet or too dry, it can greatly diminish the alfalfa crop’s feed quality and cause economic loss to producers. Therefore, monitoring of alfalfa moisture content while baling is critical for producers to maintain hay quality and maximize profits. Currently, there are several different types of moisture sensing technologies available for round balers. But, concerns exist regarding their accuracy and repeatability during hay baling. Therefore, objectives of this project are to 1) Establish a protocol for coring methodology to assess the variation of moisture within a round alfalfa hay bale, and 2) Compare and contrast sensing accuracy and repeatability of different hay moisture sensing technologies. A coring methodology was established to determine the average moisture within a round bale based upon the way a sensor in a round baler chamber would determine the bale moisture; by looking at the moisture contents along the round bale diameter. This method was then compared with the more traditional method of using radial cores only to determine the whole bale moisture content. A sensor testing stand was developed to perform comparative testing between the sensors on the same alfalfa hay bale and collect core samples of material immediately after it was formed. Six commercially available moisture sensors were selected to measure moisture at four pre-determined locations on hay bales. After the sensor measurements, core samples were extracted from the exact same locations to determine actual moisture using oven-drying method. The moisture measurements were conducted during three growth stages and bales were formed with three approximate moisture contents of 10%, 15% and 20%. Six different cuts of alfalfa of the same variety were used to capture all the measurements. A seventh cut was also performed for moisture measurements with the alfalfa baled at 15% and the same growth stage, but different baler compression cylinder pressures (250, 400, and 800psi). Actual moisture content was across different sampling locations were compared to understand moisture distribution and establish coring protocol. Sensor and oven-dried measurements were compared to determine accuracy and repeatability of sensing technologies. Results showed that sensors and oven-dried measurement varied for all the sensors for every growth stage and baling moisture levels, with one sensor exhibiting lowest variability in its readings. The comparison identified the most accurate and reliable sensor among the ones currently available. A second year of testing was also conducted to validate the research from the first year of testing. Future research needs to be conducted to identify correlation between the testing stand readings and actual hay baler moisture sensor readings.

In the United States, the Energy Independence and Security Act of 2007 mandates the annual production of 136 billion liters of renewable fuel in the US by 2022 (US Congress, 2007). As the nation moves towards energy independence, it is critical to address the current challenges associated with large-scale biofuel production. The biomass logistics network considered consists of three core operations: farmgate operations, highway-hauling operations, and receiving facility operations. To date, decision-making has been limited in post-production management (harvesting, in-field hauling, and storage) in farmgate operations. In this thesis, we study the impacts in the logistics network resulting from the selection of one of four harvest scenarios. A simulation model was developed, which simulated the harvest and filling of a Satellite Storage Location (SSL), using conventional hay harvest equipment, specifically, a round baler. The model evaluated the impacts of four harvest scenarios (ranging from short, October-December, to extended, July-March), on baler equipment requirements, baler utilization, and the storage capacity requirements of round bales, across a harvest production region. The production region selected for this study encompassed a 32-km radius surrounding a hypothetical bio-crude plant in Gretna, VA, and considered 141 optimally selected SSLs. The production region was divided into 6 sub-regions (i.e. tours). The total production region consisted of 15,438 ha and 682 fields. The fields ranged in size from 6 to 156 ha. Of the four scenarios examined in the analysis, each displayed similar trends across the six tours. Variations in the baler requirements that were observed among the tours resulted from variability in field size distribution, field to baler allocations, and total production area. The available work hours were found to have a significant impact on the resource requirements to fulfill harvest operations and resource requirements were greatly reduced when harvest operations were extended throughout the 9-month harvest season. Beginning harvest in July and extending harvest through March resulted in reductions in round balers ranging from 50-63%, as compared to the short harvest scenario, on a sub-regional basis. On a regional basis, beginning harvest in July and extending harvest through March resulted in baler reductions up to 58.2%, as compared to the short harvest scenario. For a 9-month harvest, harvesting approximately 50% of total switchgrass harvest in July-September, as compared to harvesting approximately 50% in October-December, resulted in reductions in round balers ranging from 33.3- 43.5%. An extended (9-month) harvest resulted in the lowest annual baler requirements, and on average lower baler utilization rates. The reduced harvest scenarios, when compared to the extended harvest scenarios, resulted in a significant increase in the number of annual balers required for harvest operations. However, among the reduced harvest scenarios (i.e. Scenario 3 and 4), the number of annual balers required for harvest operations showed significantly less variation than between the extended harvest scenarios (i.e. Scenarios 1 and 2). As a result, an increased utilization of the balers in the system, short harvest scenarios resulted in the highest average baler utilization rates. Storage capacity requirements were however found to be greater for short harvest scenarios. For the reduced harvest scenario, employing an October-December harvest window, approximately 50% of harvest was completed by the end of October, and 100% of total harvest was completed by the third month of harvest (i.e. December). / Master of Science