Abstract:    As an important subject leading the innovation of China′s agricultural production and management system, farmer′s cooperatives play a vital role in the process of transforming agricultural development mode and promoting agricultural modernization. In recent years, with the strong support of national policies, cooperatives have developed rapidly. By the end of 2018, there were 2.173 million farmer′s cooperatives. However, in the rapid development of cooperative economy, there are still many problems to be solved. On the one hand, some cooperatives lack a good management system, which leads to the internal management chaos of cooperatives and restricts their healthy development. On the other hand, the function of cooperatives has shifted, and the right of management has been taken into the hands of individual rural elites as a tool for them to grab financial funds. Cooperatives are an important carrier for the country to implement the rural vitalization strategy. The innovation of cooperative is not only related to the welfare of hundreds of millions of rural residents, but also related to the transformation and upgrading of agricultural economy and the smooth implementation of the rural vitalization strategy. How to promote the innovation of cooperatives and make their development more standardized has become an urgent problem to be solved.
    With the continuous advance of agricultural modernization and the gradual change of consumption mode, cooperatives are facing the transformation of management and marketing mode. In order to optimize the operation and management mode, some cooperatives began to hire professional managers, which extended the concept of professional managers from enterprises to cooperatives. Professional managers are people who are employed by economic organizations, have a high level of professional knowledge and skills, and specialize in management activities. Agricultural professional managers are a new type of professional farmers that have developed in recent years. They are constantly cultivating new types of production and operation entities such as cooperatives, family farms and agricultural enterprises. They are a professional group that is continuously developing and growing under the background of "who will and how to plant the land", which specializes in large-scale and intensive agricultural production and operation.
    The purpose of hiring professional managers for cooperatives is to improve their operation and management, enhance their innovation level and achieve their sustainable development. However, can professional managers effectively improve the innovation level of cooperatives? At present, there are few studies to systematically explore this issue and no enough credible empirical evidence has been found. More importantly, it is theoretically impossible to make sense of the problem. On the one hand, hiring professional managers will bring principal-agent problem. According to the "Quiet Life Hypothesis", as hired employees, professional managers pay attention to the stable development of cooperatives and may ignore those arduous, complex and risky innovation activities. On the other hand, compared with ordinary farmers, professional managers have a higher level of professional knowledge and skills. In management and marketing activities, they usually have unique insights and rich experience, which is of great help to the improvement of cooperative management and marketing innovation. Theoretically, we cannot accurately determine the impact of the hiring professional managers on cooperative innovation. This not only causes the lack of scientific basis for the correct evaluation of the impact of hiring professional managers on the innovation of cooperative, but also causes the current stage of the disputes over the sustainable development strategy of cooperatives cannot be resolved.
   Exploring the new path of farmer cooperatives innovation is an urgent requirement for the implementation of rural vitalization strategy. This paper examines the impacts of hiring professional managers on the innovation of farmers′ cooperatives using farmers′ cooperatives data from Sichuan province. Using propensity score matching and endogenous switching regression approach, we find that the level of management innovation and marketing innovation of farmers′ cooperatives will be significantly improved after the employment of professional managers. Moreover, we find that the positive impact is heterogeneous due to area of land differences. Besides, the results of case study show that the above results are robust. Finally, through the potential mechanism test, we find that the employment managers can indirectly improve the innovation level of cooperatives by improving the degree of Internet application, organizational learning ability and knowledge absorption ability.
    Based on the conclusion, we get the following enlightenment: (1) Cooperatives should be encouraged to actively employ professional managers. If cooperatives want to improve their level of innovation, hiring professional managers is an effective way. Compared with ordinary farmers, agricultural professional managers have richer human capital and can better manage all aspects of cooperative operation. At present, the development of agricultural professional managers is still in the primary stage. First, it is necessary to improve the qualification certification system for agricultural professional managers to ensure the effective supply of agricultural professional managers. Secondly, cooperatives should establish and improve the salary assessment mechanism for agricultural professional managers and the government should establish effective subsidy policies to help cooperatives retain agricultural professional managers through various measures. Thirdly, the government should establish and improve the supervision mechanism of agricultural professional managers and effectively improve the effectiveness of supervision by establishing relevant laws and regulations. (2) Relevant measures should be taken to promote the positive impact of hiring professional managers on cooperative innovation. The research results of this paper show that the cooperatives hire professional managers will have a positive impact on innovation by improving the degree of Internet application, organizational learning ability and knowledge absorption ability. Therefore, agricultural professional managers should strengthen the training of cooperative members and guide them to use the Internet proficiently. Through the training, cooperative members can learn more new technologies and knowledge. And it will enhance their organizational learning ability and knowledge absorption ability.

Key words: management innovation, marketing innovation, professional manager, principal agent, endogenous switching regression