Study on the Improvement of a Grain Harvester (I) -Threshing Force of Rice-

수확기(收穫機)의 성능향상(性能向上)에 관(關)한 연구(硏究)(I) - 수도(水稻)의 탈립저항력(脫粒抵抗力)에 관(關)하여

Threshing forces of seven varieties, that is, three Japonica type varieties-Irri 348, Irri 345, and Milyang 15, and four Indica type varieties-Milyang 23, Irri 342, Suweon 294 and Suweon 287-, which have been cultivated in the standard fertilization field being at Chungnam Provincial Office of Rural Development, Youseong, Chungnam-do, they were measured every other day in the period from September 28 to October 20 which were included the proper harves ting time. Also the threshing forces were checked in three-dimensional directions. Relationships between threshing forces and moisture contents of the unthreshed rice were examined in the laboratory as dried in the natural condition. The results of this study were as follows; 1. The mean threshing force of Japonica type varieties was about 1969r. and that of Indica type varieties was about 113gr. when external force was loaded in the direction parallel to the grain. 2. The threshing force bent to the grain was about 9.8through 28.2gr. equal to 7 through 21 percent to the threshing force parallel to the grain in Indica type varieties meanwhile about 59.8 through 115.0gr equal to 33 through 50 percent in Japonica type varieties. 3. Under the warmer temperature than $0^{\circ}C$, the change of threshing forces was not great in this experimental period on the harvesting dates. 4. The threshing force decreased s lightly as moisture content decreased in natural drying under the shade after cutting. 5. The threshing force of the lower portion was a little biger than that of the upper portion in an ear.

충남농촌진흥원(忠南農村振興院) 포장(圃場)에서 표준시비법(標準施肥法)으로 재배(栽培)한 Japonica형(型) 품종(品種) 이이(裡里)348호(號), 이이(裡里)345호(號) 및 밀양(密陽)15호(號) 3개斗(個)와 Indica ${\times}$ Japonica hybrid형(型) 품종(品種) 밀양(密陽)23호(號), 이이(裡里)342호(號), 수원(水原)294호(號)의 4개(個), 계(計) 7 개(個) 품종(品種)에 대해 적정수확기간(適定收穫期間)을 중심(中心)으로 9월(月)28일(日)부터 10월(月)20일(日)까지 2일간격(日間隔)으로 3축방향(軸方向)에 대(對)하여 탈립저항력(脫粒低抗力)을 측정(測定)하였다. 10월(月)1일(日) 채취(採取)된 시료(試料)를 실험실(實驗室)에서 자연건조(自然乾燥)시키면서 함수율별(含水率別) 탈립증항력(脫粒拯抗力)을 측정(測定)하였다. 본(本) 연구(硏究)의 결과(結果)는 다음과 같다. 1. 외력(外力)이 지경(枝梗)과 평행방향(平行方向)으로 작용(作用)될 경우 Japonica형(型) 품종(品種)의 탈립저항력(脫粒低航力) 평균(平均) 113grdljTEk. 2. 외력(外力)이 지경(枝梗)과 $90^{\circ}$ 측방향(側方向)으로 작용(作用)될 경우의 탈립증항력(脫粒拯抗力)은 평행방향(平行方向)과 비교(比較)하여 Japonica형(型) 품종(品種)은 33~50%인 59.8~115.0gr이었고, Indica ${\times}$ Japonica hybrid형(型) 품종(品種)은 7~21%인 9.8~28.2gr으로 현저(顯著)히 작았다. 3. 기온(氣溫)이 영하(零下)로 강하(降下)하지 않은 본실험기간중(本實驗期間中) 예취일(刈取日)에 따른 탈립심지항력(脫粒甚至抗力)의 변화(變化)는 크게 없었다. 4. 예취후(刈取後) 자연건조(自然乾燥)에 따른 탈립심지항력(脫粒甚至抗力)은 함수율(含水率)의 감소(減少)와 함께 감소(減少)하였다. 5. 이삭 부위별(部位別) 탈립서항력(脫粒鼠抗力)은 상부측(上部側)에 비(比)해 하부측(下部側)에서 약간 큰값을 나타냈다.