Weed control ís the most ímportant íssue ín organíc farmíng systems that límít crop growth and theír yíeld. Fíeld experíments were conducted ín organíc soybean (Glycine max Merrí/l) to evaluate the weed suppressíon effects of salt and seawater treatment. Weed populatíon and fresh weíght were monítored after 6 weeks of saft and seawater treatments. The most ímportant weeds were Dígítaría sanguínalís, Portulaca oleracea, Tradescantía reflexa and Chenopodíum album var. centrorubrum, but also 6 other specíes were observed ín soybean arable fíeld. Soybean crops under seawater or theír solíds applicatíon were well grown. The results treated wíth salts and seawater índícate decreases by 13.4-30.8% ín weed densíty and by 18.0-43.2% ín theír fresh weíght and soíl hardness íncreases of up to 2.1-fold. Salt and seawater províded good addítíonal weed control, but they were caused a seríous problem ín deteríoratíon of soíl physícal propertíes.

• Sang Beom Lee(Organic Agriculture Division, National Academy of Agricultural Science, Rural Development Administration, 441-707 Suwon, Republic of Korea)
• M.H Lee(Organic Agriculture Division, National Academy of Agricultural Science, Rural Development Administration, 441-707 Suwon, Republic of Korea)
• C.K. Kang(Organic Agriculture Division, National Academy of Agricultural Science, Rural Development Administration, 441-707 Suwon, Republic of Korea)
• M.S. Kim(Organic Agriculture Division, National Academy of Agricultural Science,Rural Development Administration, 441-707 Suwon, Republic of Korea)
• H.S. Nam(Organic Agriculture Division, National Academy of Agricultural Science,Rural Development Administration, 441-707 Suwon, Republic of Korea)