Elucidation of nitrogen dynamics in a snow-covered area with the goal of establishing a low-load fertilization system

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07932
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Rural environmental engineering/Planning
• Research Institution: Hirosaki University
• Principal Investigator: ENDO AKIRA 弘前大学, 農学生命科学部, 准教授 (70450278)
• Research Collaborator: KATO Koh
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 積雪寒冷地 / リンゴ園 / 土壌 / 窒素循環 / 施肥 / 溶脱

Outline of Final Research Achievements

This study was conducted in the apple orchards of gray lowland soil (Fujisaki-cho), brown forest soil (Hirosaki-shi) and Andosol (Tsuruta-cho) in Aomori Prefecture. Specifically, we had carried out the soil pore water analysis and soil environmental observation using chemical composition analysis and field monitoring system during continuous period, including dormancy period of apple trees, which is the snowfall and/or snow melting season. From various observation results such as electrical conductivity and quantitative results of anion and cation concentrations, it was revealed that the substances in the soil leached out at the once in a short period during the snow melting period. From the above, we found important findings in establishing a low-load fertilization system that the importance of autumn fertilizer application is small in view of leaching in heavy snow areas and the negative impact on the environment is larger.

Free Research Field

農地環境工学

Academic Significance and Societal Importance of the Research Achievements

青森県のような積雪寒冷地のリンゴ生産では融雪水の浸透による肥料成分の溶脱を防止するため、融雪後に施肥を行う春肥が推奨されている。しかし秋肥を行わないと施肥遅れに起因する障害が見られることもあり、他県においては秋肥を指導している。樹園地における無機態窒素の浸透流出特性が、施肥と降水のタイミングおよび窒素吸収特性に依存することが近年になり明らかにされてきた。しかし、融雪を伴った無機態窒素の溶脱挙動や樹園地の窒素循環機構の詳細はまだ解明されていないため、果樹の生育面と土壌の環境面の双方から推奨可能な施肥体系・土壌管理技術を確立するために、樹園地の窒素循環機構を明らかにする意義は大きいといえる。