Basic field experiment for the compatibly of sustainable agriculture and regeneration of RDB populations in rice paddy

两项试验的结果和讨论如下：1）RDB动植物的野外种群动态对于大水蝽和潜甲虫种群，标记再捕获法可用于检测其在研究区的生境利用、栖息格局、迁入率和残留率。虽然每个物种在生活史中都利用稻田、池塘、灌溉道和河流等多种生境，但它们的主要繁殖场所是用于粮食生产的稻田。在RDB植物物种的情况下，它们的栖息地是稻田，池塘和灌溉方式。但新发现的是，它们能在以池塘或湿润稻田等永久性水体为主要生境的旱田中生长良好。2）围隔层次RDB种群的更新实验在大学农场，对RDB种群的生境条件进行了分析。特别是在丽莎水稻免耕覆盖栽培方式下，与常规水稻生产方式相比，水生昆虫的种类更为丰富。3）农业生态位理论初步研究综合两种研究方法，认为日本农业生态位的最佳模式是低投入、低干扰的水稻可持续生产。在稻田丰富的情况下，多样化的种植制度与传统品种，如根据丽莎的红色类型水稻栽培。

Results and discussions of two examinations are shown as followed;1) Field population dynamics of RDB animals and plantsFor populations of the Giant water bugs and the Diving beetle species of Cybister, their marked and recaptured method could be applied to detect their habitat use, disparsal pattern and immigration and residual rate in examined area. Although each species use multi-habitat including rice fields, pond, irrigation way, and river in their life cycles, their main reproductive place was rice paddy fields for food production. In the case of RDB plant species, their habitat were rice paddy fields, pond and irrigation ways. However, they can grow well in dry rice paddy fields as our new finding, of which habitat is mainly permanent water such like a pond or wet-type rice fields.2) Experiments for regenerating RDB populations in mesocosm levelIn university farm, some experiments were carried out for analyzing habitat condition for each RDB populations. Especially in LISA rice cultivation method with no-tillage and legume mulching, diverse water insect populations were abundant than conventional rice production systems. Furthermore, in practical examinations in RDB population field area, diversified cropping systems with traditional crops might be available for regenerating RDB populations.3) Tentative theory of agro-biotopeAcordings to integration of two kinds of examinations, the most effective biotope for practical situation in Japanese agriculture is sustainable rice production with lower input which reduce disturbance to RDB populations. In the case of abundant rice fields, diversified cropping systems cultivated with traditional variety such like a red-type rice under LISA.