Ecological Traits of Weed Flora with Different Soil Moisture in Fallow Upland Fields

This survey of weed population with different soil moisture in fallow upland fields (2000～2003) was conducted to investigate information on weed flora and its ecology in 2003. Weeds of fallow upland fields composed of 60 species belonging to 23 families. Among 23 families, 14 weed species belonged to Asteraceae (23.3%) were the biggest family, Poaceae were 9 species (15.0%), Cyperaceae were 6 species (10.0%), and, Fabaceae were 5 species (8.3%), respectively. However, weeds of different soil moisture in fallow upland fields composed of 32 species belonging to 9 families. Among 9 families, Asteraceae (25.0%) and Poaceae (25.0%) of 8 weed species were the biggest family, Cyperaceae were 5 species (16.0%) and Fabaceae were 4 species (13.0%), respectively. Dominance by species based on number, coverage, frequency, and plant height occurred at Filed cutting area were Digitaria sanguinalis (56.5%)>Setaria viridis (42.1%)>Erigeron annuus (26.8%)>Echinochloa crus-galli (10.4%)>Cyperus iria (10.1%). Also, Dominance at Soil dressing area were Digitaria sanguinalis (100%)>Setaria viridis (59.6%)>Erigeron canadensis (21.7%)> Glycine soja (9.6%)>Cyperus iria (9.1%), Dominance at Slope land area were Digitaria sanguinalis (100%)>Setaria viridis (61.8%)>Echinochloa crus-galli (26.6%)>Persicaria blumei (23.6%)>Fimbristylis miliacea (4.4%), respectively. Weed occurrence at Filed cutting, Soil dressing and Slope land area was 53.7, 118.3 and 84.5 g , respectively. Simpson's index was calculated to 0.14～0.17, which showed that weed occurrence with different soil moisture in fallow upland fields was various