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区域环境与生态

李成芳,曹凑贵,汪金平,潘盛刚,叶成,叶威,刘铠,曾金凤.稻鸭、稻鱼共作生态系统中稻田田面水的N素动态变化及淋溶损失[J].环境科学学报,2008,28(10):2125-2132

Dynamic variations and losses of N in floodwater of paddy fields in integrated rice-duck and rice-fish ecosystems

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入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.

Abstract：Field experiments were conducted to study dynamic variations of NH₄⁺-N、NO₃^--N and TNin floodwater and percolation water,and drainage losses of N fertilizer in rice-duck (RD) and rice-fish (RF) complex ecosystems.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 Nin floodwater and percolation water.Compared with conventional rice fields(CK),in RDand RFthe 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.

Key words：Floodwater percolation water nitrogen integrated rice-duck system integrated rice-fish system