长江中下游至珠江三角洲一带,江河纵横,湖泊众多,素称水网地区,地势平坦,土质肥沃,水热丰富,生长季节在200天以上,属亚热带湿润季风气候,为我国工农业生产的重要基地。但农业生产仍以单一的小农经济结构为主,对建立农林结构的农田生态系统,并未得到人们的足够认识。水网地区的气候资源得天独厚,但它主要受季风控制,气候多变不稳,灾害性天气频繁,如春季的倒春寒、秋季的低温冷害,是水网地区后季稻产量不稳的原因之一。 Middle and lower reaches of the Yangtze River to the Pearl River Delta area, many rivers, many lakes, known as the water network area, flat, fertile soil, rich in water and heat, growing season in more than 200 days, is a subtropical humid monsoon climate for China’s industrial and agricultural production base . However, agricultural production is still dominated by a single small-scale peasant economy, and farmland ecosystems for establishing agroforestry structures have not been sufficiently recognized by people. Hydrological network is unique in climate resources, but it is mainly controlled by monsoon, the climate is volatile, frequent disastrous weather, such as spring in late spring and cold in autumn, is one of the reasons for the instability of water quality of the latter quarter of the hydropower area .