中文摘要：

通过田间试验研究了稻鸭、稻鱼共作复合生态系统稻季田面水及渗漏水中各形态N素的动态变化及N肥的渗漏损失量．结果表明，水稻生长期间，田面水中N素形态以NH4^＋-N为主，渗漏水中则以NO3^--N为主要形态；施肥有利于田面水和渗漏水各形态N素含量的提高．相对于常规稻作处理（CK），稻鸭（RD）、稻鱼共作（RF）时田面水的pH、NH4^＋-N含量和TN含量显著增加，渗漏水的NO3^-N和TN含量降低，而渗漏水NH4^＋N无明显变化．所有处理田面水中NH4＋-N／TN在施肥后第3天达到最大，随后降低；而所有处理NH4^＋-N／TN的均值相当．对各处理的N素淋失分析可知．处理RD与RF的肥料N潜在淋失率分别为2．72％、2．58％，低于CK处理（2．99％），表明稻鸭、稻鱼共作可以减少施人N肥潜在的下渗淋失，同时稻鱼共作减少N肥淋失的效果好于稻鸭共作．

英文摘要：

Field experiments were conducted to study dynamic variations of NH4 losses of N fertilizer in rice-duck （RD） and rice-fish （RF） complex ecosystems. -N,NO3 -N and TN in floodwater and percolation water, and drainage The results indicated that NH4＋ -N was the predominant form of nitrogen in floodwater while NO3- -N was the predominant form of nitrogen in percolation water. Fertilizer application could increase the concentrations of all forms of N in floodwater and percolation water. Compared with conventional rice fields （ CK）, in RD and RF the pH and concentrations of NH4＋ -N and TN in floodwater were increased, while concentrations of NO3 -N and TN decreased and NH4＋ -N concentrations remained unchanged in percolation water. On the 3rd day after fertilizer application, the ratio of NH4＋ -N/TN was the highest, and thereafter decreased. There was no difference of mean ratios of NH4 - N/TN among three different treatments. The results also showed that the potential maximal ratios of fertilizer N leaching in RD and RF were 2.72% and 2.58% , respectively, lower than 2.99% in CK, suggesting that RD and RF could reduce loss of N fertilizer and the effect of reducing N fertilizer loss was better in RF than in RD.