Research the Dynamic Relationship between the Amount of Fertilizer Inputs and Major Grain yields in Jilin Province

摘要

To investigate the relationship between the amount of fertilizer inputs and grain yield and its dynamics change in Jilin Province during 1971-2010. Adopt to 7-year moving average method to calculate the trend for crop yield of per unit area yield of grain in 40 years. Correlation analysis shows that there is a significantly positive correlation between the trend yield and the fertilizer inputs per unit area. The model of law diminishing returns is established by the regression analysis. Also it shows the fitting degree during 1971-1981 between the grain yield per unit area and the fertilizer inputs per unit area meets the first stage of the model. Marginal yield raises with the increase of the amount of fertilizer inputs per unit area and the grain yield raises significantly. The fitting degree meets the second stage of the model during 1981-2010. Marginal yield approaches zero gradually with the increase of the amount of fertilizer inputs per unit area. Grain yield per unit area reaches a stable value. In order to improve the grain yield in Jilin Province and based on the present fertilizing amount, the agricultural production should adopt to scientific methods and suitable time of fertilization, and gradually increase the promotion and application of new fertilizers.