This study was conducted to investigate the effects of summer green manure crops as an alternative for imported expeller cake fertilizer on environment-friendly lettuce production. Sunnhemp, soybean, sudangrass, and sorghum, as summer green manure crops, were evaluated under the condition of a plastic film house. In the amount of nitrogen supplied through cultivation of green manure crops, soybean plot, which supplied 187 kg ha-1, was the highest, followed by sorghum plot, 156 kg ha-1. Since all green manure plots supplied more nitrogen than that required by soil testing, it was possible to replace the nitrogen supply of expeller cake fertilizer with the amount of nitrogen produced by green manures for autumn lettuce cultivation. N nutrient balances in sunnhemp, sudangrass, soybean, and sorghum plots were 13 kg ha-1, 28 kg ha-1, 30 kg ha-1, and 38 kg ha-1, respectively. The initial yield and total yield of lettuce showed no significant difference in green manure plots compared to the expeller cake plot, but . It was thought that all green manure crops could be substituted for expeller cake fertilizer used as nitrogen fertilizer, but it would be necessary to adjust the cultivation period and reduction point according to the type of green manure in order to maintain the C/N ratio, nitrogen supply, and nitrogen balance suitable for lettuce production.

ABSTRACT
서 론
재료 및 방법
    시험장소
    녹비작물 재배와 유박 시비
    토양 및 식물체의 무기성분 분석
    상추 재배
    통계분석
결과 및 고찰
    녹비 무기성분 함량 및 질소 공급량
    토양화학성 변화 및 양분수지
    상추 생육특성 및 수량
적 요
REFERENCES

• 최장용(충청남도농업기술원 친환경농업과) | Jang-Yong Choi (Department of Environmentally Friendly Agriculture, Chungcheongnam-do Agricultural Research and Extension Services, Yesan 32418, Korea)
• 윤여욱(충청남도농업기술원 친환경농업과) | Yeo-Uk Yun (Department of Environmentally Friendly Agriculture, Chungcheongnam-do Agricultural Research and Extension Services, Yesan 32418, Korea)
• 강희경(공주대학교 원예학과) | Hee-Kyoung Kang (Department of Horticulture, College of Industrial Science, Kongju National University, Yesan 32439, Korea) Corresponding author