稻鸭共生对稻田水生生物群落的影响

通过稻田共生的田间试验，对稻鸭共生稻田水体中的藻类植物和水生动物的种类、数量及生物量进行测定分析。结果表明：在水生生物种类组成上看，稻田水体中藻类植物共39属，水生动物共33属，都以对照为最高。藻类植物在数量上以对照为最高，为6.075×106ind/L，显著高于放鸭小区，在生物量上以放4只鸭为最高，但差异不显著。不同藻类构成比较分析，在数量上以硅藻、蓝藻和绿藻占优势，分别占个体总数的33.96%、29.45%和23.58%，在生物量以蓝藻和裸藻占优势，它们分别占总生物量的48.23%和26.72%，养鸭后绿藻的优势度下降，裸藻、蓝藻优势度上升。各类水生动物的数目和生物量均按水源区、对照区、少鸭区、多鸭区的顺序下降，但差异不显著。其数量上以原生动物优势，而生物量上以蚌虫占优势。在多样性方面，藻类植物以水源区和放4只鸭为最高，香农多样性指数都为2.03，水生动物多样性指数以放6只鸭为最高，香农多样性指数为1.765。可见，稻鸭共生增强了稻田生态系统的自然属性。

Effects of Rice-Duck Farming on Aquatic Community in Rice Fields

Through the experiment with rice-duck intergrowth in rice field, the species, number and biomass analysis of the algae and the aquatic animals were made. The result shows that, there were 39 algal genera and 33 aquatic animals’ genera in the water of these test fields, and the highest genera were in the control field. In the four field, waterhead field, control field, 4-duck field and 6-duck field, the highest algal density was taken in the control field, which the number was 6.075×106ind/L, and the difference was significant. The highest algal biomass was in 4 duck field, and the difference wasn’t significant. The quantitative dominant algal genera were Bacillariophyta, Cyanophyta, Chlorophyta, which accounted for 38.96%, 29.45% and 23.58% of the total algal amount, respectively, while the biomass dominant algae genera were Cyanophyta and Euglenophyta, accounting for 48.23% and 26.72% of total biological quality, respectively. In the water of the rice-duck symbiosis paddy, the dominance of Chlorophyta declined, and that of Euglenophyta and Cyanophyta increased. Both the number and biomass of aquatic animals decrease with an order of waterhead field, control field, 4-duck field and 6-duck field, but the difference wasn’t significant. The quantitative dominant aquatic animals’ genus was Protozoa, while the biomass dominant aquatic animals’ genus was Conchostraco. The highest biodiversity index of algae was in the waterhead and the 4-duck field, which the Shannon-Weiner index was both 2.03, and that of aquatic animals was in the 6-duck field, which the Shannon-Weiner index was 1.765. The conclusion was that the nature attribute of ecosystem with rice-duck intergrowth was increased.