Symbiotic coexistence of paddy field and Urban ecosystem

Abstract

The paddy field is primarily used as an agricultural system to produce rice, which is the main staple food in Japan. The paddy field plays an important role in the various ecosystem functions such as flood control, groundwater recharge, improvement of water quality, local climate mitigation, fish culture and other non-rice productions, fostering culture and landscape, and maintaining biodiversity, among others. Paddy fields provide an important habitat to foster biodiversity. The remaining rice paddies in urban regions have an important role to alleviate the deterioration of the urban environment. In the first section, no-tillage cultivation studies carried out so far to investigate its effects on biodiversity in paddy fields are explained. Results show that spiders and carabid beetles prefer no-tillage soils in which the litter accumulate to the soil surface where abundant decomposers exist. Actually, in various types of crops, the density of soil-inhabiting predators such as spiders and carabid beetles is known to be higher in no-tillage or reduced-tillage cultivation field. The results also suggest that predation by spiders (especially lycosid spiders) is an important mortality factor for older larvae of the straight swift, and the effect is greater for the no-tillage paddy fields than the conventional paddy fields. In the following sections, an integrated rice farming method that uses crossbred ducks being practiced since 150 years ago, known as Aigamo farming in Japanese, is described. The rice-duck farming is a promising technique for producing organic rice in Southeast Asia. The farming system involves organic food certification systems, organic farmers’ cooperatives, community-wide organic farming, localized technical extension and educational services, and integration of farms and rice-duck. An experiment undertaken for the simultaneous cultivation of rice plants and baby crossbred ducks at the university farm in Fuchu, Tokyo, shows the effects of the release of crossbred ducks on the growth and quantities of rice plants, weeds, and diversity of the arthropod community.