(一) 问题的提出作物生长与土壤物理环境变化密切相关。当今对土壤结构的概念,有了新的认识,并日趋一致。不少研究资料指出:“改善结构是耕作的核心问题。”太湖流域杭嘉湖平原,是在人类社会由渔猎向农业转变的时期开始种稻。大约在西周时期,当时是轮荒阶段——采用的是火耕水耨的轮荒阶段。到汉代圩田便应运而生,开始沤田制,直至唐宋时期采用稻麦两熟。明清强调干耕晒白,清末到解放前夕“客帮人”带来了 (A) the issue of crop growth and soil physical and environmental changes are closely related. Today’s concepts of soil structure have gained new understanding and are becoming more consistent. Many research materials point out: “Improving the structure is the core issue of farming.” The Hangjiahu Plain in the Taihu Lake basin started to grow rice during the period when human society shifted from fishing to agriculture. Around the Western Zhou Dynasty, it was a wilderness phase - using a wilderness phase of fire hydration. To the polder of the Han Dynasty came into being, began to Tian system, until the Tang and Song dynasties using rice and wheat two. Ming and Qing dynasties emphasis on dry and white sun, the Qing eve of the liberation of “passenger help” brought