Abstract: The located experiment was conducted in Taoyuan Experimental Station of Agroecosystem Research of the Chinese Academy of Sciences. The result indicated that both fertilization system and water management pattern significantly affected the transformation process and productive efficiency of the nutrient and water. The productive efficiency was 4.5 kg/kg for N fertilizer application only, 8.8 kg/kg and \{8.0 kg/kg\} for NP and NPK fertilizers combined, respectively. The yieldincrease rate was 56.5% under organic residue recycled, however it could be up to 79.8% based on organic residue combined application with NPK fertilizer. The yieldincrease rate was 62.2% with fertilizer application development and for 79.8% 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 ecosystem with different water irrigation pattern. Water needed by irrigation was about 5 838m\+3/hm\+2 and the annual variation efficient of irrigation water required was 8.3%, of which 71% by growing late rice. Water distribution in the paddy field with control irrigation (CI) showed that transpiration and evaporation counted 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 feed (RF). Irrigation between July and September consumed 68% of the total water required. Irrigation productive rate is 3.67 kg/m3 in rice biomass and 1.48 kg/m3 in grain output. It was concluded that for growing double rice in double rice region of red soil, the thinner water layer must kept in early rice and the periodical rational irrigation was very important for late rice.

Key words: the paddy ecosystem, water, nutrient, transformation processes, productive efficiency