Off-farm processing : development of a forage collection scheduling model
Streeton, Helen J.
The collection of straw and grasses for use in various industries is expanding, as there is a need for material in both the traditional forage markets and in the bio-products and biofuel industries. Because these materials tend to be bulky and difficult to transport there is a need for managers to optimize the performance of their collection process. The model focuses on two different types of collection, baled material and loose chops. The material is mowed, allowed to dry in field, and then collected with either a baler or a forage harvester. The model uses a combination of historical data and managerial inputs to compute the approximate costs of the material. The model also identifies the average and maximum delays involved in the collection of the material. These outputs allow a manager to identify areas where processing costs are high, and areas where there might be significant delays or excess capacity in the process. The model was verified by comparing results to information that was collected from two different facilities. One facility dealt primarily with fresh forage, while the other dealt exclusively with sun-cured forage. The model was verified to within 15% of the actual data, however, with continued refining of the input costs the modeled results can be much closer to actual operating costs. After verification, a number of scenarios were tested to determine the models’ greatest sensitivities. The effects of changing fuel costs, labour costs, and the length of the working day were all investigated. It was found that the repair and maintenance costs had a larger effect then either the fuel or labour costs for most types of equipment. It was also found that the model was very sensitive to the capacity of the equipment. For the model to provide an accurate representation of forage collection, the system must be adjusted to reflect the costs associated with a particular facility. After these adjustments are made, the operator can investigate the effects of changes on his/her particular operation.