This paper presents a mathematical model for forecasting the productio
n of some agricultural commodities. This method takes into account the
general trend of the time series and random fluctuations about this t
rend. It has the merits of both simplicity of application and high for
ecasting precision. In particular, the forecast values of the model ar
e more precise than those of other models such as the index smoothing
method and the grey dynamic model, for data sequences with large rando
m fluctuations. The case study of the silkworm cocoon production in Zh
ejiang province shows the merits of the model.