عنوان مقاله [English]
In the last decade the use of chemical fertilizers have been followed environmental consequences adverse such as water and soil pollution and health problems for humans and other living things. As the use of chemical fertilizers could create serious risks for the environment and public health, the aim of this study is to determine the optimal combination of fertilizers for crops in the Goharbaran region of Sari using Goal Programming model and the Game Theory, and finally, cropping pattern in the current and optimal fertilizer consumption for crops is discussed using Positive Mathematical Programming. Required data for this study has collected with interview of 250 farmers during the years 2014-2015. The results of this study showed that the consumption of fertilizers for all crops have not been optimal by representative farmers. Therefore, current fertilizer consumption for all crops is more than optimal value. Based on results of positive mathematical programming, despite of constantan the total cultivation level, profits increased 3% in optimum fertilizer consumption rather than current fertilizer consumption.