벼-콩 답전윤환재배지에서의 잡초발생동태를 구명하기 위하여 수행하였던 결과를 요약하면 다음과 같다. 1. 벼 건답직파재배지에서는 피의 우점현상이 두드러졌으며, 연작에 의해서 계속 증가하는 경향이었고, 콩재배지에서는 피, 좀명아주 및 (좀)바랭이가 문제잡초로 제기되었다. 2. 벼 건답직파재배에서 콩 재배로 또는 콩재배에서 벼 건답직파재배로 답전윤환(畓田輪換)을 함으로써 잡초의 발생량을 크게 감소시킬 수 있었으며, 너도방동사니, 올방개, 올챙이고랭이, 벗풀 및 수생잡초의 발생이 크게 억제되는 경향이었다. 3. 답전윤환재배시(畓田輪換栽培時) 동일 작물을 2년 이상 연속재배(連續我培)하면 잡초의 발생량이 크게 증가하였다.
Weed communities in the dry-direct seeded rice(Oryza sativa L.), soybean(Glycine max(L.) Merr.), and dry-direct seeded rice-soybean rotation system from the transplanted rice field were investigated in order to identify a change in weed species by paddy-upland rotation. Echinochloa species was the most dominant species in the dry-direct seeded rice and their great increase was observed in the continued practices of dry-direct seeded rice. Echinochloa spp., Chenopodium ficifolium, and Digitaria spp. were identified as the major weeds in soybean cultivation in paddy field. Practice of soybean rotation in the dry-seeded rice reduced weed occurrence, particularly at the soybean after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr soybean compared to the continued cultures of rice or soybean. In addition, cultivation of dry-direct seeded rice or soybean culture in the paddy rice field seemed to be helpful for suppression of perennial weeds(Eleocharis kuroguwai, Cyperus serotinus, Scirpus juncoides) and aquatic weeds(Monochoria vaginalis, Sagittaria spp. Potamogeton distinctus).
