UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Mathematical model for the selection of haying machinery Jeffers, John Percival Weldon


Surveys of hay harvesting machinery in the Lower Fraser Valley of British Columbia indicated wide variation in sizes of machines employed on farms of comparative size. Quality hay depends on 1. the types of forages grown 2. the stage of growth at which the crop is harvested and 3. the influence of weather as it effects curing. Bleaching, leaf shatter, and leaching of soluble nutrients are the worst hazards to which the crop is exposed. The system of harvesting will affect the time the crop is exposed to the effects of the weather. Methods that reduce the time needed for curing in the field tend to produce a better quality hay. Factors affecting the selection of least cost combinations of machines used in sequence are 1. the cost which bears a linear relationship to the capacity of the machines, 2. the area they have to service and 3. the time available for the performance of the operations. The time available for a sequence of operations to be performed in this case is a function of the weather. A study of the weather of the Lower Fraser Valley indicated that in any given ten day period during the months of June, July and August, the probabilities of two or more, three or more or four or more open days for field curing hay are constant. Using this linear cost capacity relationship, acreages from ten to one hundred acres, and the time available obtained from weather probability data, a mathematical model is derived to select least cost machinery combinations for hay harvesting in the Lower Fraser Valley. A computer programme for the I.B.M. 7040 digital computer is also developed.

Item Media

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.