ABSTRACT Winter-flooded paddy field is an agricultural method which putting a water among the winter, it is paid attention as an environmental friendly agriculture. Especially, it is said, winter-flooding is control paddy weeds and there is the farming potential that the annual rice yield is high. However, there is no detailed research about the effects of weed communities by winter-flooding, as the purpose of this study, we investigated the effects of the inhibition of weed communities (life cycle, harmful weed) by winter-flooding at a shore of Inba Lake, Chiba Prefecture, Japan, and compared them to paddy weeds in a dry paddy field. Methods examined the plant height (cm) and the cover degree class of all appearance species in each quadrant frame (1 m2). Quadrant in the two type paddies were 10 frames (D1-D10) at the control, and were 10 frames (W1-W10) at the treatment (Figure 1). In a winter-flooded paddy field, species number and plant volume of winter-annual plants decreased in the third winter after winter-flooding, In particular, the plant volume of Alopecurus aequalis, Cardamine flexuosa decreased significantly. We considered that the cause of this decrease was due to the depth of flooding (more than 10 cm). Eleocharis kuroguwai and Echinochloa oryzoides, which are perennial plants, Sagittaria trifolia, which is an annual plant, increased in a winter-flooded paddy field in the third summer after winter-flooding. We considered that these species grew thicker at places where the seeds germinated, and grew easily, because the conservation situation of the seeds fitted well under the winter-flooding conditions. They started to grow immediately after the drainage of water. The period of drainage coincided with increasing light intensity and temperature. In addition, the annual rice yield of the third year after winter-flooding was higher than that of the habitual practice rice field．
Cite this paper
nullKaneko, K. and Nakamura, T. (2011) Effects of the inhibition of weed communities by winter-flooding. Agricultural Sciences, 2, 383-391. doi: 10.4236/as.2011.24050.
 Ministry of Agriculture, Forestry and Fisheries (2007) MAFF’s biodiversity strategy. Ministry of Agriculture, Forestry and Fisheries, Tokyo, Japan.
 Chiba Prefecture (2008) Biodiversity Chiba Prefecture strategy. Chiba Prefecture, Chiba, Japan.
 Kurita, H., Mineta, T., Ishida, K., Ashida, T. and Yagi, H. (2006) Environmental potential of winter-flooding rice field for the wetlands restoration. Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 74, 713-717.
 Iwabuchi, N. (2003) Importance and application in winter-flooding rice field—Circulation type technology support ecosystem maintaining ecosystem. Rural Area and Environment, 19, 50-59.
 Iwasawa, N. (2003) It revives by non-tillage. Sosinsha, Tokyo.
 Yamamoto, H., Ohhata, K. and Yamamoto, K. (2003) The effects of water flooding and provision of the food for wintering ducks on rice fields—A preliminary study for establishing a stable wintering duck population at Katano-kamoike Ⅲ. Strix, 21, 111-123.
 Mineta, T., Kurita, H. and Ishida, K. (2004) Potential of Winter-flooding rice field in Regard to farming and the multifunctionality—Analysis of status by questionnaire and interview survey to operative farmers. Transactions of Rural Planning, 6, 61-66.
 Kaneko, K. and Nakamura, T. (2009) Winter-flooding has an effect on paddy weeds. Japan Association for Landscape Ecology, 14, 67-72.
 Braun, B.J. (1964) Pflanzensoziologi. Grundzuge der vegetationskunde. Springer-Verlag, Wien.
 Chsaka, H. (1965) Auto-ecology of Alopecurus aequalis. Weed Research, 4, 20-27.
 Sumiyoshi, T. and Nakano, E. (2008) Winter-flooding in Ariake costal area, weeds problem of non-till mulching system. Journal of Weed Science and Technology, 53, 35.
 Nakagama, A., Miyawaki, K., Nagano, Y. and Shimo- shikiryo, K. (1990) Changes of weeds-vegetation due to the differences in the paddy-field utilization-form—Soil water adaptability and viable seeds-distribution of the weeds emerging during the winter cropping-period. Bulletin of the Experimental Farm Faculty of Agriculture, Kagoshima University, 15, 25-36.
 Arai, M. and Miyahara, M. (1962) Physiological and ecological studies on Barnyard Grass (Echinochloa crus- galli Beauv.var.oryzicola Owhi.) Ⅳ on the death of seeds in process of dormancy awaking. Japanese Journal of Crop Science, 31, 190-194. doi:10.1626/jcs.31.190
 Asano, H., Terasawa, T. and Hirose, S. (1981) Effect of different temperature and light intensity levels on growth in early stage of barnyardgrass. Journal of Weed Science and Technology, 26, 36-40. doi:10.3719/weed.26.228
 Yamagishi, J. and Takeuchi, Y. (1975) Ecological characteristic of Eleocharis kuroguwai—Development ecology. Journal of Weed Science and Technology, 14, 54-56.
 Sawai, K., Nishi, S. and Adachi, A. (1975) Ecological characteristic of Sagittaria triforia—Second report Generation from seed. Journal of Weed Science and Technology, 14, 76-78.
 Ito, K. (1989) Ecology and control methods studies of Sagittaria trifolia L. in paddy field. Journal of Weed Science and Technology, 34, 13-14.
 Ito, K. (1988) Spread of herbicide and Holocene of arable weeds. In: Yano, S., Ed., The Vegetation of Japan— Ecology of the Invasion and the Disturbance, Tokai University, Tokyo, 145-158.
 Mineta, T., Koizumi, N. and Ishida, K. (2009) Contribution of winter-flooding in multi-functionality of paddy fields—Some notes in a case of biota conservation function in Tajiri-Shinpo Miyagi prefecture. Transactions of Rural Planning, 6, 335-340. doi:10.2750/arp.27.335