长江流域稻田生态系统的水分和养分转换过程

田间模拟施肥进步和灌溉模式的定位试验在中国科学院桃源农业生态试验站进行。结果表明施肥制度和水分管理模式显著地影响水分和养分的转化过程和生产效益。单施N的产量效应为4.5 kg/kg，而NP或NPK配施养分总的产量效应分别为8.8 kg/kg和8.0 kg/kg；有机物料循环的增产率为56.8%，在有机物料循环的基础上配施NPK化肥最大的增产率可达到80.1%；化肥应用的进步可使水稻产量增长62.5%或通过施肥实现的水稻产量中由于化肥应用所占的贡献份额为38.4%，有机无机肥配合水稻产量增长80.1%，或通过施肥达到的产量中有机无机肥配合所占的份额为44.4%。本区双季稻年灌溉需水量为5838 m³/hm²，年变异C.V = 8.3%。晚稻灌溉占全年的71%，7~9月是灌溉需水高峰期，占全年灌溉量的68%。生产灌溉效率 (灌溉水量与产量之比)：生物量3.67 kg/m³，精谷量1.48 kg/m³。常规管理田间水分分配为：蒸散占1/2，翻耕整地占1/6，植物构成占1/21，田间渗漏占1/14，其它环境耗水 (维持) 占1/5。耕灌雨养管理翻耕整地和田间渗漏比例过高。不同灌溉处理试验表明：双季稻生产的灌溉，以早稻保持水层灌溉，晚稻按需配额灌溉的模式比较适宜。

Experimental Study on Water and Nutrient Transformation in the Paddy Ecosystem of the Yangtze Valley

The located experiment was conducted in Taoyuan Experimental Station of Agroecosystem Research of the Chinese Academy of Sciences. The result indicated both fertilization systems and water management pattern significantly affected the transformation processes and production efficiency of the nutrient and water. The production efficiency was 4.5 kg/kg for N fertilizer application only, but 8.8 kg/kg and 8.0 kg/kg for NP and NPK fertilizer combined, respectively. The yield-increase rate was 56.8% in the organic residue recycle case, however it could be up to 80.1% based on organic residue combined application with NPK fertilizer. The yield-increase rate was 62.8% with fertilizer application development and 80.1% with inorganic-organic fertilizer combined. In other words, in the case of optimum fertilization system, the largest contribution portion of inorganic fertilizer applied was 38.4% while that of inorganic-organic fertilizer combined was 44.4%. There were obvious differences in water transformation in paddy fields with different irrigation patterns. Water distribution in the paddy field with control irrigation (CI) showed that transpiration and evaporation accounted for 1/2, plowing and preparing land for 1/6, plant constitution for 1/21, field leakage for 1/14, and other environment consumption (maintenance) for 1/5. Whereas, the proportion of plowing and preparing land and field leakage was too large under rain-fed (RF) conditions. Water needed for irrigation was about 5838 m 3 /hm 2 and the annual variation efficiency of irrigation water required was 8.3%, of which 71% for growing late rice. Irrigation between July and September consumed 68% of the total water required. Irrigation production rate was 3.67 kg/m 3 in rice biomass and 1.48 kg/m 3 in grain output. It was concluded that for growing double harvest rice in the Yangtze Valley, the thinner water layer must be kept in early rice and the periodical ration irrigation was very important for late rice.