Organic Cultivation Of Rice Fields Of Animal Diversity And Ecological Environment Effect And Influence

Over the rapid development of organic rice farming in China in recent years, the evaluation of its ecological and evironmental effects on agricultural ecosystem is urgently needed.In order to reveal the ecological and evironmental effects of organic rice farming, we carried out a comprartive study on biodiversity and genetic diversity of neutrual organisms including gastropods, Oligochaeta and zooplanktons in both organic paddy fields and conventional paddy fields. In addition, the inorganic elements including heavy metals, pestcide residues in the two kinds of paddy fields were also compared in this study. The main results obtained were as followes:1There were three kinds of Oligochaeta, Amynthas hupeiensis, Pheretima guillemi Michaelsen and Eisenia foetida being collected in footpath of organic rice fields but only two kinds i.e. Amynthas hupeiensi and Eisenia foetida in footpath of conventional rice fields. The number of Oligochaeta in footpath of organic rice fields was significantly higher (p<0.05) than that in footpath of conventional rice fields. The abundance (d) and biodiversity index (H) of Oligochaeta community in footpath of organic rice fields were0.573and0.952while those in footpath of conventional rice fields0.558and0.659respectively, indicating that the footpath of organic rice fields can provide a much better environment for Oligochaeta organisms than the footpath of conventional rice fields.2There were four genera of zooplanktons i.e. Daphnia, Moina, Cyclops and Microcyclops being collected in organic rice fields but only three genera i.e. Daphnia, Moina and Microcyclops in conventional rice fields. The number of zooplanktons in organic rice fields was significantly higher (p<0.05) than that in conventional rice fields. The abundance (d) and biodiversity index (H) of zooplankton community in organic rice fields were0.775and1.334while those in conventional rice fields0.78and0.866and those in ditch1.25and1.155respectively, indicating that the organic rice fields can provide a much better environment for zooplanktons than the conventional rice fields.3Six species of gastropods i.e. Bellamya aeruginosa, Parafossarulus striatulus, Alocinma longicornis, Bithynia fuchsianus, Radix swinhoei and Galba pervia were collected in organic rice fields (located in island within Baoying lake) while only three species of gastropods i.e. Parafossarulus striatulus, Bithynia fuchsianu and Galba pervia were collected in conventional rice fields (located in island within Baoying lake). The number of gastropods in organic rice fields was significantly higher (p<0.05) than that in conventional rice fields. The abundance (d) and biodiversity index (H) of gastropods community in organic rice fields were0.907and1.405while those in conventional rice fields0.514and0.939respectively, indicating that the organic rice fields can provide a much better environment for gastropods than the conventional rice fields.4RAPD polymorphism locus and genetic diversity index (RI) as well as COI gene’s Nucleotide Polymorphism index (CI) of Radix swinhoei population from organic rice fields in Xindang villege (with RI as0.581, CI as0.5152) were much higher than those of Radix swinhoei population from conventional rice fields in Xindang villege (with RI as0.516, CI as0.01675), indicating that organic rice farming can increase the genetic diversity of gastropods such as Radix swinhoei.5The contents of Pb、Cd、Hg、As、Cu、Zn of water samples, soil samples and spider samples from conventional rice fields were somewhat or significantly higher than those from organic rice fields, indicating that organic rice farming can inprove the inorganic environment in paddy fields.6Harmful ingredient contents tested in organic rice were somewhat or significantly lower than those in Pollution Free rice.Conclusions:The performance of animal biodiversity, genetic diversity and inorganic environmental indexes in organic paddy fields strongly suggest that the ecological and evironmental effects of organic rice farming on agricultural ecosystem are much better than conventional rice farming.