大中型拖拉机残值模型的研究

折旧是农业生产中的一项重要成本,而科学的折旧要以正确估计农业机器的残值为基础,ASABE的残值函数对估计农业机器残值提供了通用的方法,但这些模型是根据美国的实际情况模拟,并不能适合中国的实际情况.该文以上海农场近15年出售的116台拖拉机历史数据为观察样本,以机龄和年平均工作小时数为自变量,对6种不同的备选残值模型进行了回归分析和比较,在此基础上优选了双平方根模型为最佳残值模型,并用实际观察数据进行了验证.结果表明,用ASABE的模型来预测中国大中型拖拉机残值偏差很大,而本模型的预测精度是满意的,可用来预测中国大中型拖拉机残值;在残值模型变量中,机龄为决定残值的主要因素.

Model for remaining value function of the large and medium-sized tractors in China

Depreciation is a significant cost associated with farm ownership. Remaining value functions established as ASABE standards have provided a popular means of estimating costs, but these functions are not responsive to the conditions of farm machinery and agricultural economy in China, the test forecast errors are not acceptable. In order to develop new remaining value functions for large and medium-sized tractors, 116 recent tractor auction sales data in Shanghai State Farm were collected, by different Box-Cox transformations and regression methods, six proposed models with explanatory independent variables of tractor age and average yearly use hours were analyzed and compared, and the double square root model was selected as best one finally. The real test data also show this model can obtain satisfactory forecast results, and tractor age is the main factor for determining tractor remaining value.