Developing resource-circulation rice farming using bamboo biomass in Satoyama

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19860
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Kanazawa University
• Principal Investigator: Nisikawa Usio 金沢大学, 環日本海域環境研究センター, 准教授 (00391136)
• Co-Investigator(Kenkyū-buntansha): 勝見 尚也 石川県立大学, 生物資源環境学部, 准教授 (40769767) ; 伊藤 浩二 岐阜大学, 地域協学センター, 助教 (30530141)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 環境配慮型農業 / 里山資源 / 無農薬稲作 / モウソウチク / ケイ酸

Outline of Final Research Achievements

This study explored the inorganic and organic substances produced or leached from bamboo powder and the effects of these substances on weeds, rice yield and biodiversity. Three years of field experiments showed that the application of bamboo powder increased rice yield in the first year of the experiment, but such positive effects on rice yield was not observed after the second year of the experiment. We hypothesized that available phosphate or free iron oxide in the soil affected silicon uptake by rice plants, that in turn, led to enhanced rice yield. In addition, another hypothesis emerged - nitrogen fixation by iron-reducing bacteria in the soil led to enhanced rice yield following ground bamboo application. Ground bamboo application had positive effects on the abundance of Tetragnatha spiders, but effects on macroinverterbrates were variable among taxa.

Free Research Field

保全生物学

Academic Significance and Societal Importance of the Research Achievements

竹の粉砕物を水稲農業に活用する試みは、一部の篤農家の間で行われているが、竹粉砕物が水稲収量に与える影響の安定性評価や、米の収量の増加をもたらすメカニズムに関してはこれまで解明されてこなかった。本研究でも、メカニズムの解明までは至っていないが、いくつか有力な仮説を提示することができた。今後、竹を活用した無農薬稲作技術が確立されれば、米の品質を損なわずに安全・安心な米の収量を向上させることが可能となり、米の品質の低下や化学物質・重金属の残留が懸念される既存の循環農法と差別化が図れる。これにより、里山のバイオマスの利活用を軸とした、資源循環型農林業の創生への新展開が期待される。