• Korean Journal of Weed Science
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• v.31 no.1
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• pp.41-48
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• 2011

This survey of weed population by different soil moisture with paddy-upland rotation was conducted to investigate information on weed flora and its ecology between two years. Weed species were assessed in April : 2009, 2010. Soil samples were taken from each study plot to assess the impact soil moisture on the occurrence and abundance of dominance weed species. Soil water of poorly drained field ranged from 10.2~18.2% more than 11.8~14.3% of somewhat poorly drained field. Weeds of fields composed of 19 species belonging to 12 families. Among 12 families, 6 weed species belonged to Compositae (31.6%) were the biggest family, Cruciferae were 2 species (10.5%), and Rubiaceae were 2 species (10.5%), respectively. Youngia japonica had the highest summed dominance ratio(SDR) (97.0%) and followed by Conyza canadensis (92.1%), Galium spurium (35.3%) and Hemistepta lyrata (28.4%) of somewhat poorly drainage in 2009. Artemisia princeps the highest SDR (100%) and followed by Stellaria alsine(55.2%), Y. japonica (38.3%) and Nasturtium officinale (28.5%) of poorly drainage in 2009. And, Stellaria alsine had the highest SDR (86.8%) and followed by Alopecurus aequalis (77.7%), Astragalus sinicus (68.7%) and Y. japonica (46.3%) of somewhat poorly drainage in 2010. S. alsine the highest SDR (93.7%) and followed by A. aequalis (78.6%), Nasturtium officinale (31.3%) and Y. japonica (30.4%) of poorly drainage in 2010. Simpson's index was calculated to 0.12~0.23, which showed that weed occurrence with different soil moisture in paddy-upland rotation and between years was various. Similarity coefficient between years was 43.0% (2009) and 74.2% (2010), which indicate a low diversity because of the moisture in the agro-ecosystem.