<論説>「火耕水耨」再考

Abstract

華北、淮北の平原では、その降水量から言って天水稲作は不可能であるが、夏季畑作物の非灌漑栽培は基本的には可能である。しかし低地では畑作物の湿害と塩害がある。従って低地では排水を優先し畑作を奨励する政策と、灌漑を優先し稲作を奨励する政策とが共に可能であるが、前者は旱魃害を、後者は湿害と灌漑による二次的塩害をかえって促進すると言う矛盾を抱えている。これら二つの政策の葛藤は古代から現代にまで続けられており、どちらの政策が採用されるかは、時代の経済的、政治的、社会的、文化的要因のバランスによっている。一方、江南では火耕水耨と呼ばれる粗放な稲作が行なわれていたが、この農法は、かつてアジア稲作圏の大沖積平野共通の栽培法であったと考えられ、草を焼き、籾を直播し、自然の増水をもって雑草を抑制する共通点をもっていた。この農法は、上質の商品米需要には応えられず、低地水制御の進展と共に消減して行ったと考えられる。華北では、少なくとも漢代からは米が商品化しており、権力者によって稲作が促進され、ときに上記の灌漑と排水の矛盾が顕在化することがあった。しかし大運河によって安価な江南米がもたらされるようになって、稲作のインセンティブは大きく失われた。一方、江南では大運河による上質米需要の急増によって、低地水制御が進み、集約的な稲作が火耕水耨に代った。

In China north of the Huai River rainfall is sufficient for the unirrigated cultivation of summer crops other than rice. In low-lying areas however poor drainage and soil salinity are chronic hazards for those crops. Therefore, two alternative strategies are conceivable : one giving a priority to drainage and encouraging the cultivation of non-rice crops, the other giving priority to irrigation for the cultivation of rice. In either case there are hazards : in the former, there is greater vulnerability to drought, and in the latter, there is the problem of excessive moisture and soil salinity for non-rice crops. Which direction of the two was emphasized in different historical periods depended on the prevailing economic, political, social, and cultural conditions. In the Yangtze basin, it is known that an extensive mode of cultivation of rice called huo geng shui nou 火耕水耨 (literally, ''cultivation with fire and weeding with water") was common in the Han period. It is characterized by burning grass and straw in the spring, seeding directly without transplanting, and suppressing weed growth by natural inundation. This method is considered to have been universal in the large alluvial plains subject to seasonal inundation elsewhere in the Asian rice zone. Rice producted by this method, however, was not suitable in quality for the market. In northern China, rice was a commercial crop as early as the Han period and its production was promoted by the demand for rice among the upper strata of society. This sometimes exposed the contradiction between the two strategies mentioned above. By the construction of the Grand Canal, however, the incentive for the production of rice in northern China largely disappeared, since rice could then be transported cheaply from the Yangtze basin. In turn, the market demand for high-quality rice spurred on improvements in lowland water control and intensive cultivation replaced "cultivation with fire and weeding with water" in the Yangtze basin.