Changes in soil, flora and fauna in rice paddies under continuous organic farming with no agrochemicals inputs

2017 Fiscal Year Final Research Report

• Project/Area Number: 26310304
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 特設分野
• Research Field: Food Cycle Research
• Research Institution: The University of Tokyo
• Principal Investigator: KOBAYASHI KAZUHIKO 東京大学, 大学院農学生命科学研究科(農学部), 教授 (10354044)
• Co-Investigator(Kenkyū-buntansha): 内野 彰 国立研究開発法人農業・食品産業技術総合研究機構, 中央農業研究センター, 上級研究員 (20355316) ; 鳥山 和伸 国立研究開発法人国際農林水産業研究センター, 生産環境・畜産領域, 再雇用職員 (30355557) ; 山田 晋 東京大学, 大学院農学生命科学研究科(農学部), 助教 (30450282) ; 宮下 直 東京大学, 大学院農学生命科学研究科(農学部), 教授 (50182019) ; 山岸 順子 東京大学, 大学院農学生命科学研究科(農学部), 教授 (60191219) ; 程 為国 山形大学, 農学部, 准教授 (80450279) ; 二宮 正士 東京大学, 農学生命科学研究科, 教授 (90355488)
• Project Period (FY): 2014-07-18 – 2018-03-31
• Keywords: 有機農法 / 土壌 / 窒素 / リン / 雑草 / 生物多様性 / イネ / 水田

Outline of Final Research Achievements

Studying an organic rice farming system developed by a farmer, we found the following mechanisms of this system.
This organic farming system is very labor-efficient due to the omission of fertilizer applications and weeding, which greatly contributed to this farm's economic sustainability.
The rice yield was much lower only a few years after conversion to this system than that in conventional farming, but the former yield approached the latter as the practice is continued for several years. One of the reasons for this increase of rice yield due to the continued organic management is the increased availability of soil nitrogen and phosphorus as the off-season weeds are incorporated across the years. The continued practice of organic farming also reduced the population of a summer-season weed species and increased the population of natural enemies like spiders.

Free Research Field

農業環境工学