Estimatinglong-term fertilizer demand in Iran's agricultural production

During the past four decades, the need for chemical fertilizers in Iran has continuously increased. Each year, millions of dollars are spent on buying chemical fertilizers and the Government also provides a large amount of subsidies to help farmers in supplying chemical fertilizers. As a consequence, the related environmental hazards have led to increased consumer health risks from exposure to specific compounds such as the nitrate accumulation in agricultural products. Predicting the amount of fertilizer needed over the long-term is an essential key for ensuring food security and public health for the future. To estimate the required amount of fertilizer, data on the area under cultivation, production and yield for a 45-year period (1962 to 2007) were collected from the databases of the Ministry of Agriculture, the Statistical Center of Iran and the Food and Agriculture Organization (FAO). Among the causal models applied, the Tenkorang model with variables included―yield, previous year yield, cultivation area and pervious year fertilizer consumption― gave the best estimate of the amount of fertilizer demanded with a correlation coefficient of 0.94. Coefficients for the model were calculated based on data belonging to the period 1962 to 1991. The accuracy of the model was demonstrated by comparing the predicted and actual values for the years 1993 to 2007. According to the Tenkorang model, the total amount of chemical fertilizers required for Iran’s agricultural production in 2021 will be apporximately 5 million tons.