HIRAI Hideaki, AKAHANE Ikuko, FUKUDA Tadashi. Background and details of submission of demanding paper on soil education to MEXT, emphasizing the importance to adopt soil in the coming revise of the MEXT curriculum guidelines. Japanese Journal of Soil Science and Plant Nutrition. 2015. 86. 6. 595-598
HIRAI Hideaki, SHINOZAKI Ryosuke, HOSHINO Koichi. A change in the number of times of the term "soil" appeared in the fields of science, social studies and living environments of the government guidelines for teaching at elementary school and a proposal of the contents suitable for teaching soils in the field of the science at elementary school. Japanese Journal of Soil Science and Plant Nutrition. 2011. 82. 1. 52-57
Application of image analysis to evaluation of paddy rice root colors and the relationship between the root colors and silica contents in the rice plant and soil solution. Bulletin of the research farm, faculty of Agriculture, Utsunomiy University. 2000. 17. 1-9