The challenges to and technical innovations in the mechanization of rice production in China

Rice is the grain crop with the largest growing area and highest yield per unit area in China. The development of rice production mechanization is closely related to the Chinese economy. Mechanization can be adopted in land preparation, the seedling nursery, transplanting/seeding, irrigation, field management, harvesting, and drying. The level of mechanization is high in the north but low in the south, high on dry land but low in the paddy field, and high in wheat but low in rice. To meet the urgent demand of farmers for rice production machinery, the Chinese government made the "Study on appropriate technology and key implements for rice mechanization production" a national key project. The Ministry of Agriculture launched a 100-country demonstration project for rice production mechanization in the whole country. Mechanization for land preparation, irrigation, and field management is fairly high, but is rather low for rice planting and harvesting. To solve the key technological problems that limit rice planting mechanization, we made the "Study on the high-speed rice transplanter" a key project. The project aims to develop and manufacture a high-speed rice transplanter, high-speed seedling-throwing machine, and seedling machines. Rice-growing areas in China can be divided into three kinds according to geographic location and cropping system: single-crop rice area in the cool temperate zone, rice and wheat rotation, and double-crop paddy rice area. The diversity in ecotype, crop species, and farming systems requires diversity in rice cultivation technology and farm implement system. China now mainly applies the technique of conventional seedling nursing and planting. Direct seedling provides convenient conditions for mechanization and has labor saying, reduced cost, and high production efficiency. The technology of raising potted rice seedlings in the greenhouse and surface planting was applied in the 1990s in China. Compared with the conventional technique of raising rice seedlings and transplanting, it has high operation efficiency, good quality of rice seedlings, fast regreening of seedlings, more low node-order tillers, a high degree of maturity, high yield, and ease of operation. Another key problem that restricts rice mechanization is the diversity in rice harvesting. The whole-feed combine harvester has strong adaptability but has high energy consumption and stripping losses. The head-feed combine has strong suitability and good performance but has a higher cost and lower working efficiency. The stripping-type combine harvester has low energy consumption, high efficiency, and low cost but has a high loss rate, high breaking rate, and low adaptability and reliability. To speed up mechanization of rice production in China, we need to heighten technical innovation capability, strengthen international technical cooperation and exchange, extend the industrialization of agricultural machinery service, and develop strategies for implementation.