雑草害調査と草取り体験を通して除草剤の意義と課題の理解を促す教育実践

抄録

  We conducted a hands-on learning program to promote the understanding of the benefits and problems of herbicides among students through the experience of weed threats and hand weeding. A total of 120 fourth-grade elementary students participated in this program. To investigate the effect of weeds, green soybean, Egyptian spinach, and green onion were cultivated for two months. Weeds were initially seeded throughout the entire field. Later, the students weeded half of the field to avoid damage to the crops, while the remaining crops were exposed to weeds throughout. We observed that the weeds decreased crop yields. Initially the Egyptian spinach and green onion grew slowly in comparison to the weeds and consequently, their yields declined considerably due to the interception of sunlight by the weeds. In contrast, green soybeans grew rapidly and managed to intercept the sunlight faster than the weeds. Hence, the loss to the yield of green soybeans was relatively small. The students acquired a basic knowledge of weeds and herbicides through lectures; however, they observed the crop damage caused by the weeds and experienced hand weeding in the field. Further, they understood the effects of weeds on crops through their hands-on experiment. Finally, they realized the difficulties of agriculture and regarded herbicides in a positive light. However, the educational aspects that could assist the students to recognize the benefits and problems of herbicides was insufficient.