水稻噴用2, 4-D除草試驗

Experiments of Weeding Applied 2,4-D in Rice Paddy Field

楊方平(F. P. Young)

《中華農業研究》 11卷4期 (1962/12) Pp. 1-10

https://doi.org/10.29951/JARC.196212.0001

摘要

1．本試驗爲探討水稻田噴用2, 4-D除草之可能性，及其對水稻生育與產量之影響。全試驗設四種2,4-D噴用時期（第一期作爲水稻移植30、44、52、62日，第二期爲移植19、26、32、38日），各噴用時期分設每10公畝噴用2,4-D20、35公分（濃度均爲千分之一）及手取除草四平準，採用4×4複因子試驗，田間設計用逢機區集法排列，重複四次，小區面積10平方公尺。
2．水稻田之雜草，如鴨舌草、螢藺、水馬齒等對2,4-D感受性強者，每10公畝噴用20公分，其死亡率達80%以上，噴用數量較多，死亡率亦高。2,4-D對雜草之剷除效力，比手取除草者爲大。但少部份之雜草，如田字草等，則感受性較弱，不容易枯死。
3．水稻生育早期噴用2,4-D除草，對植株之伸長及分蘗，均受到抑制。移植後生長日數較長者，所受影響較小，噴用數量（兪心）多，則受害更大。水稻生育期間受影響，至成熟期，其株高及有效分蘗亦減低。第二期作噴用者，所受之影響較一期作爲輕。
4．水稻噴用2,4-D除草對產量之影響，第一期作比第二期作爲大。第一期作移植30日噴用，產量減低30~40%，移值44日噴用減低6~17%，迄移殖52日噴用，差異不顯著。由噴用時期不同觀察，移植52日噴用者產量最高。噴用教量不同之比較，則使用2，4-D除草均較手取除草之產量爲低，噴用數量多者差異更大。第二期作噴用時期對噴用數量之連應不顯著。噴用時期不同比較，移值26日噴用者產量聶高，與各噴用時期之差異顯著。各噴用數量不同比較，則以手取除草之產量爲高，較噴用2,4-D除草各處理之差異，均達顯著程度。
5．水稻配合噴用2，4-D除草，第一期作須移植50日以上，但此時之水稻中耕除草已完畢，似不適宜配合使用。第二期作噴用2,4-D對水稻影響較小，移植後30日左右噴用，對水稻不致有大影響，如第一、二次以慣例之手取除草，再配合噴用2,4-D一次，尚可施行，但噴用時之各項技術問題，均須加么探討，始可避免損失。

並列摘要

1. To know whether 2. 4-D is effective when used as the weed killer is the purpose of this experiment. In addition, its effects to rice growth and yield caused by the spraying of 2, 4-D were also investigated. The chemicals, in same concentration 1/1,000, were applied individually with the amount of 20, 35 and 50g per 10 ares at four growing stages, ie. 30, 44, 52 and 62 days after transplantation in the first crop and 19, 26, 32 and 38 days in the second crop. The ordinary hand-weeding method was used as the control. 4×4 factorial block design, 4 repeats were employed.
2. In the plots of 20g treatment, more than 80% of mortality were found in some weeds, such as Monochoria vaginalis Presl, Scirpus erectus Poir. and Callitriche stagnalis Scop. which are sensitive to 2,4-D. The weed like Marsilea quadrifolia L. was relatively insensitive. On the other hand the percentage of weed mortality was found to increase according to the increase of dose applied. Generally, weeding ability of 2, 4-D was higher than those of hand-weeding.
3. The Plant height and tillering number were observed to decrease in the plots of spraying at early stages of rice growth, while slight effect were found in those plots of spraying at later stages. The more amount of 2, 4-D applied the more injury on rice plant occurred. This injury was generally maintained till the harvesting stage. The injury of rice by 2, 4-D was more serious in the first crop than in the second crop.
4, In first crop, about 30-40, 6-17 and 0 percent of yield decreasing were investigated, respectively, in the plot spraying at 30, 44. and 52 days after transplantation, when compared with the hand-weeding plot. In second crop, spraying at 26 days after transplantion produced the highest yield. The differences from other treatments were statistically significant. Meanwhile, hand-weeding plot yielded more grains than any plot of spraying 2, 4-D in both two crops, the differences were also significant.
5. Using 2, 4-D as the weed killer, the spraying must be done at more than 50 days after the transplantation in the first crop. At this time the necessary weeding and intertillage are usually completed. Therefore, this weeding method can not be recommended in the first crop season. In the second crop, the injury of rice by 2, 4-D is relatively slight when spray at 30 days after tranplantion, therefore, it can be recommeded that the ordinary hand-weeding is employed at the first and second time of weeding, and 2, 4-D application is used at 3rd weeding time. In order to aviod the yield decreasing, some practical problems concerning the application of 2, 4-D must be solved.