Mechanisms controlling heterogeneous distribution of fertilizer-derived P in soil microstructure

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H02116
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: YAMAGUCHI Noriko 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境研究部門, グループ長補佐 (80345090)
• Co-Investigator(Kenkyū-buntansha): 橋本 洋平 東京農工大学, (連合)農学研究科(研究院), 准教授 (80436899)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 蓄積リン / 堆肥 / XANES / 固体NMR

Outline of Final Research Achievements

This study revealed that when soil P levels reached nearly the maximum P sorption capacity of soils due to the long-term fertilizer application, the surplus P was accumulated as calcium phosphate (Ca-P). Particularly in the compost amended soils, Ca-P was heterogeneously distributed and formed micro hot spots. Such segregation of Ca-P in soil microstructure functions to prevent P from sorbing on soil minerals strongly. Solid-state NMR measurements for soil extraction residues revealed that soluble and insoluble soil Ca-P species can be differentiated by combined uses of Truog and acetic
acid extractions.

Free Research Field

土壌化学

Academic Significance and Societal Importance of the Research Achievements

化学肥料由来のリンが土壌中で一様に分布するのに対し、堆肥施用によって、土壌微細構造内でのリンの化学状態の多様性を作り出すことができることが示された。肥料価格の高騰にともない、効率的な施肥の重要性がさらに高まってきた。堆肥施用によりリンがカルシウム型リンとして局在することで土壌鉱物への強固な吸着が抑制されていることを示した本研究成果は、堆肥をはじめとする有機質資材の積極的活用を後押しする根拠となる。