Dynamic Study on the Economic Life Span of Farm Machines

According to the practical used circumstances of farm machines, on the basis of studying the existing interrelated documents, utilizing technical economics theory, two kinds of hypotheses were proposed. Under the hypotheses the model to calculate the economic life span of farm machines was established. Meanwhile, some directions about the application of the model were given. Finally, the economic life span of small tractors in Gansu Province was obtained by the model.