논문 상세보기
pp.619-624
전년도 생산된 생고를 전량 환원하여 무경운 상태로 둑새룰을 피복도 8 정도로 우점시키고 그라목손으로 엽신만 고사시켜 피복도를 6으로 조절한 후 표준시비량의 20%를 감비한 상태로 중묘기계이앙하여 잡초방제, 질소 감비 효과및 벼 생육에 미치는 영향을 검토한 결과는 다음과 같다. 1. 이앙후 모의 넘어진 주율은 둑새풀 피복도 8인 경우에 37.4%, 피복도 6에서는 12.3%로 높았으나 이앙 2주일 후에는 피？도 6정도에서 대부분 정상으로 활착되었다. 2. 이앙후 둑새풀은 이앙기 진행 방향으로 넘어졌다가 1주일후에는 이삭만 다시 일어나 6월 말경 까지 서서히 노화되어 고사되었으며 그라목손 처리로 엽신만 고사된 둑새풀은 5월 상순에 고위분얼 이삭이 발생하여 일시적으로 녹화되다가 7월 상순까지 노화되면서 서서히 고사되었다. 3. 이앙후 벼 분얼성기의 잡초 발생은 피 > 방동사니> 가막사리 순으로 일부 발생되었으나 둑새풀의 우점으로 77∼78%의 잡초방제가를 보였다. 4. 둑새풀의 고사로 토양은 심하게 환원되면서 벼분얼성기에 벼와 잡초의 뿌리 일부가 부패되어 활력이 떨어졌다. 5. 둑새풀 우점구에서는 관행구보다 출수후 20일경 지엽, 차엽 및 3엽장이 길었고 엽색도 짙었으며 좌절중도 컸으나 포장도복이 약간 일어났으며 수량은 둑새풀 피복도 6에서 현미 628.5kg /10a로서 관행과 유의차가 없었다. 6. 결과적으로 둑새풀의 피복도를 6 정도 유지하여 무경운 이앙하면 수량 감수없이 시비량을 20%줄일 수 있었고 제초제를 안써도 되는 저투입 환경보전형농법이 가능하였다.
An experiment was carried out to find out the effects of water foxtail on weed control and rice yield as well as on the reduction of nitrogen application in no tillage transplanted paddy field. Paddy field was dominated by water foxtail whose soil covering degree was adjusted from 8 to 6 by treatment of paraquat (70 l /10a of solution diluted by 1, 000 times). Thirty five-day old seedling was mechanically transplanted and reduced nitrogen, 80% of conventional application was applied at the paddy field. The higher failure in seedling stand was observed at higher degree of soil covering by water foxtail. The failure of seedling stand with covering degree of 8(no paraquat) was 37.4%, while that of covering degree of 6(paraquat-treated) was 12.3%. However, the seedling stand failure was completely recovered at covering degree of six at two weeks after transplanting. The mechanical transplanting made water foxtail in the paddy field fall on the ground whose panicle part was recovered from falling sometimes after transplanting and whole plant died with slow scenesence untill the late of June. But the water foxtail affected by paraquat produced the new panicle from uppernode of stem with dead leaves at early of June and it become die slowly untill the early of July. Though several rice field weeds were observed in the order of Echinochloa crusgallis, Cyperus serotinus, Lemma paucicostata during the active tillering stage of rice, the value of weed control due to the dominance of water foxtail was 77~78%. The death and subsequent decay of water foxtail during the active tillering stage of rice induced the soil reduction which again defect the growth of rice root. The more vigerous rice growth was observed in the plot dominated with water foxtails, than control plot. The yields of rice in the water foxtail (degree 6) plot was 629kg per l0a as brown rice, the same as that of control plot. In conclusion, the no-tillage transplanting with control of covering degree of water foxtail (to degree 6) was effective in reduction of input cost such as herbicide and nitrogen fertilizer, as well as weed control without reduction of rice yield.
