| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Velvetleaf (Abutilon theoprasti Medicus) is an exotic annual weed, and often becomes a dominant weed at forage crop fields in Japan because it is adaptive, prolific, and difficult to control.In southwestern part of Japan, velvetleaf is becoming more prevalent in corn fields.
The objectives are to determine the physiological and ecological characteristics of velvetleaf, and develop a successful velvetleaf management program in corn fields.
Field experiments were conducted to study the effect of varying velvetleaf densities and planting dates on the growth and yield of corn.Velvetleaf emerging 10 days after corn emergence did not reduce corn growth or yield.Though corn growth reductions caused by high velvetleaf densities, velvetleaf produced less seeds compared with at low velvetleaf densities because of inhibiting branching.
Weedy type of velvetleaf exhibited different characters from cultivation type in view of branching, seed size and high seed output.
Fresh seeds exhibit a high degree of dormancy, and it needs for 3 months to break dormancy of velvetleaf seeds. Velvetleaf seeds population in the soil was directly proportional to the plant population in fields last year.Cultural treatments with tillage practices caused faster breaking velvetleaf seed dormancy than those without tillage.
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