Analysis of alfalfa import price fluctuation based on an HP filter model

This study analyzed alfalfa (Medicago sativa) import price features based on data from January 2008 to December 2017. First, we analyzed the main characteristics of price fluctuation. Then, a seasonal adjustment model of Census X12 was used to eliminate the influence of seasonal factors and irregular factors. An HP filter decomposition model was further used to breakdown the price series into trend series and fluctuation series. Finally, the fluctuation period was divided. This study allows us to take advantage of the fluctuation and cyclical changes in alfalfa import price to guide enterprises in trade, so as to reduce the negative effects of price fluctuation.