Abstract:   Productive service-driven innovation is one of the important modes of agricultural innovation and development in the future. It is of great significance to understand the mechanism and applicable conditions of this development mode. Taking the outsourcing service of rice and corn production as an example, on the basis of theoretical analysis, this paper constructs an econometric model and uses the OLS estimation method to investigate and verify the impact of farming season constraints on the supply of agricultural productive service, and then discusses the applicability of productive service driven innovation mode in different links of food production. From the perspective of the division of labor, the formation of a specialized service market which depends on the market scale is the premise of productive service-driven agricultural innovation. Agricultural production is a natural reproduction process. The market scale of its specialized operation includes two aspects: space market scale and time market scale. Different link farming season characteristics will lead to different market scales of specialized services. Due to the long effective operation period, relatively fixed link operation time, and the sequence of operation time in different regions according to latitude changes, the "time scale" of specialized operations in land preparation, sowing and harvesting is long, so the productive service driven innovation mode can be popularized in this kind of links. However, the "time scale" of specialized operation in pest control is too short due to the urgent operation period, low certainty of the operation time and weak regularity of operation time in different latitudes. In this kind of link, the shortage of productive service supply has its inevitability, and the applicability of productive service driven innovation mode is low. With the aging, feminization and part-time employment of the agricultural labor force, the demand for agricultural productive service will continue to rise in the future. How to take corresponding measures to promote the development of service supply may be an important content to be considered. First of all, creating conditions for mechanization is a necessary condition for deepening the division of labor within agriculture and driving agricultural innovation through productive service. China has a vast territory, and the natural environment and economic level vary greatly in different regions，limited by the topography, some areas are faced with the dilemma of using large machinery with high efficiency loss and using small machinery with low relative income. At this time, appropriate government intervention and support are needed. According to the topography, differential subsidy measures and subsidy intensity are taken for the same type of machinery or the same link of productive service, which is conducive to the promotion and application of agricultural production machinery. Secondly, free public training courses on mechanical operation and maintenance are provided for local agricultural machinery operators to further improve the efficiency of professional services and strengthen the comparative advantages of productive service. In addition, making full use of the opportunity of land transfer at this stage, encourage village collectives to guide farmers to unify the planting structure of adjacent plots, so as to create conditions for productive service organizations to fully obtain service scale economy, and so on. All these measures will contribute to developing the regional productive service supply to a higher level.

Key words: productive outsourcing service, innovation, time scale, link heterogeneity