ارزیابی آثار سیاستهای مختلف بخش کشاورزی بر شاخصهای بهره وری آن در دشت قزوین

Water is considered as the most important factor and limiting input for Agriculture in dry regions as well as Iran. Studies illustrate that decrease of 10% in water supply, causes the 0.8% decrease in GDP of Iran. Accordingly, improvement of water consumption structure in this country can be a solution for solving the water crisis. In light of the future of water shortage in this country, many economists and planners have proposed the different approach and theories which may lead to a remedy for the problem of water resources. The implementation of water productivity system, especially in agricultural sector, is one of the most important solutions which have been suggested for improving this condition because the water productivity in this sector has the lowest amount compared with other economic sectors such as industry and service.
On the other hands, the amount of supplied water is limited and the cost of supply is enormous, so improving productivity indicators has become as one of the most important policies in water resources management. The various tools are used in water resources management policies to cope with increasingly severe water shortage in the most developed and developing countries . One of the solutions have been suggested for improvement water productivity is water demand management. The policies such as water pricing, tax on inputs, tax on productions, and water supply control can affect water demand, consequently, it has a positive effect on the increase of water productivity. The objective of this paper is the assessment of the impacts of agricultural sector policies on water productivity in Qazvin plain. This research focuses on the Qazvin plain which is located in the center of the Northern Iran. The most widely used irrigation system is traditional irrigation. The population growth, low rate of water productivity, inefficient allocation of water and inappropriate cropping pattern are considered as major problems in this area.
For achieving the goal of this research, it was applied positive mathematical programming methods and maximum entropy in Qazvin Plain between 2011 and 2012.
Policy makers, especially those in the agricultural sector, are expected to be aware of the consequences of different policies and take into account farmers’ reactions to various policy situations and look for a simulation model that can ultimately help them make better decisions. The conventional method to simulate the decisions of economic agents is to create a model which reflects the limitations, opportunities, and the goals for the current situation. The PMP, which is an empirical analysis method, is of particular importance in the political economy analysis that incorporates all the available information no matter how rare. The increasing need for model simulation of behavioral functions under various technical, economic, political and environmental conditions has strengthened using the PMP with calibration capabilities that do not have the problem of excessive specialization and results in models with more parameters validation and flexibility.
In this paper, three kinds of policies were designed. 1-the increase of water price 2- a tax on input and output 3- water supply policy. The reaction of farmers was stimulated by positive mathematical programming. There are the different approach for calculation the water productivity that we used from three criteria physical productivity criterion, economic productivity criterion, and employment productivity criterion.
The results show that in addition to being water resources management policy leads to reduce water consumption, there is also economic and social effects which should be considered to the policy implementation. Also, the policy of a tax on output and input have no significant effects on physical productivity of water for other crops. On the other hands, water price policy can be as the best tools for reduction of water consumption although this policy and plan can have a negative impact on total gross margin and employment. So, it is necessary to consider all of the consequences of this policy. Furthermore, the results of productivity indices show that combined of water pricing policies (25 % increase in price) and decrease water availability (20%) provide the best situation for promotion of water productivity in Qazvin plain. Consequently, the government can improve the water productivity by the formulation of water price and water supply policies in agricultural sector.
Water is considered as the most important factor and limiting input for Agriculture in dry regions as well as Iran. Studies illustrate that decrease of 10% in water supply, causes the 0.8% decrease in GDP of Iran. Accordingly, improvement of water consumption structure in this country can be a solution for solving the water crisis. In light of the future of water shortage in this country, many economists and planners have proposed the different approach and theories which may lead to a remedy for the problem of water resources. The implementation of water productivity system, especially in agricultural sector, is one of the most important solutions which have been suggested for improving this condition because the water productivity in this sector has the lowest amount compared with other economic sectors such as industry and service.