Study On Farmers' Choice And Order Distribution In Order Agricultural Supply Chain

The contract farming supply chain realizes the effective link between farmers’ small production and the big market, and it not only guarantees the income of farmers, but also improves the stability of raw material supply for agricultural enterprises. Then it has received a wide range of promotion in our country and other area in the world. However, in the actual operation of contract farming supply chain, agricultural enterprises may face the challenge that the supply of agricultural products is uncertain apart from the reaction of market risks. The uncertainty of agricultural products is that during the agricultural products’mature period, the company purchases agricultural products according to the production contract, but the quantity or the quality of agricultural products which provided by farmers is uncertain. The condition change of agricultural products, such as the temperature and the humidity, the lack of labor input, the deliberate default of farmers, the agro-meteorological disasters and so on may result in the uncertainty of agricultural products. Such uncertainty not only increases the operation cost of agricultural enterprises, affects the stability and the reliability of agricultural supply chain, but also restricts the development of our country’s agriculture industrialization. At present, the researches on the contract farming supply chain almost deal with the risk of default from the perspective of improving the production contract, hardly response to how to deal with the uncertainty of agricultural products from the view of the company.The paper aims at the problem of agricultural products’uncertainty in the contract farming supply chain, from the perspective of purchase decision making which decided by agricultural enterprise decision maker, adopting the beforehand risk control strategy to discuss how to effectively relieve or decrease the company’s loss resulting from the uncertainty of agricultural products through the optimization of farmer selection and order allocation. Firstly, we conduct a field research on a provincial key leading company in Yunnan province. Based on the knowing of the basic information, we take a statistic analysis on the quantity of contracted farmers and its relative supply data in 2015 provided by the company, and discover that the quantity and the quality of agricultural products supplied by farmers are uncertain actually, and the uncertainty obeys the normal distribution. Secondly, considering the company’s total costs involving the process that company contract with the farmers until company finishes the acquisition of agricultural products, we develop the farmer selection and order allocation model under agricultural supply uncertainty, which uses the minimum expected total cost as the objective function. Again, according to the investigation data, we design several numerical examples. We apply genetic algorithm and particle swarm optimization to solve the examples respectively to demonstrate the effectiveness of the model and the feasibility of the algorithms. And we compare the results that solved by two algorithms with two factors, the calculating speed and the accuracy, finding that particle swarm optimization has relative advantage for solving the model.Lastly, through the sensitive analysis of model parameters, we find that the total contracted quantity which the company contracting with farmers always greater than the actual demand and with the increase of the farmers’supply instability degree, the total contracted quantity and the expected total cost are increased. We also discover that the total expected cost is added with the increase of the unit purchase cost, the unit cost of contractual development with farmers, the unit conduct service cost and the standard deviation of the supply rate respectively, and reduced with the increase of the unit shortage cost and the unit processing cost respectively. The total contracted quantity is tended to decrease with the increase of the unit purchase cost, the unit conduct service cost and the standard deviation of the supply rate respectively, and increase with the increase of the unit shortage cost, the unit processing cost and the standard deviation of the supply rate respectively. We still notice that the combination change which consists of the unit cost of contractual development with farmers, the product capacity of farmers, the mean value and the standard deviation of the supply rate has a certain effect on the selection of farmers. And with the continuous optimization of the four parameters, the probability that the farmer selected is increased, but the probability is not the same completely for that the farmers are in the same level.The research of this paper has a favor of perfecting the theory of the contract farming supply chain management, and has a positive significance on enhancing the ability of dealing with the supply uncertainty for agricultural enterprises, on decreasing the operation costs and on improving the stability of contract farming supply chain.