凍結する前の前件の土壌水分は、解凍中の土壌溶解有機物の量、組成、安定性に影響を与える可能性があります

春の融解中に大量の溶存有機物（DOM）が土壌に放出されていますが、その生物学的利用能と成分はまだ不明です。解凍中の森林土壌の水抽出物におけるDOMの量、組成、安定性は、2か月間の凍結後に研究されました。（CO2）フラックス、生分解性溶解した有機炭素（BDOC）および窒素（BDON）、紫外線吸光度および並列因子分析蛍光励起排出マトリックス。BDOC、BDON、DOC、およびDONの濃度は、最低30％WFPSであり、土壌の解凍中のDOMとBDOM濃度の両方が比較的高く、土壌の水分が低くなりました。WFPの増加に伴い、土壌DOMの支配的成分はフミン酸様物質からフルボ酸様物質に変化し、Domの生物学的起源は徐々に増加しました。タンパク質様成分は、土壌DOMの8〜20％を占め、植生の種類とWFPの影響を単純に、そしてインタラクティブに影響を受けました。結果は、冬の凍結前に50％を超えるWFPSを持つ森林土壌が大量のフルボ酸様DOMを放出する可能性があることを暗示しています。

There are large amounts of dissolved organic matter (DOM) released into the soil during spring thaw, but its bioavailability and components are still unknown. The quantity, composition and stability of DOM in water extracts of forest soils during thaw were studied after two-month freezing with 9 levels of soil moisture ranging from 10% to 90% water-filled pore space (WFPS), by measuring soil carbon dioxide (CO2) flux, biodegradable dissolved organic carbon (BDOC) and nitrogen (BDON), ultraviolet absorbance and parallel factor analysis of fluorescence excitation-emission matrices. Concentrations of BDOC, BDON, DOC and DON were lowest around 30% WFPS and relatively higher and lower soil moisture both increased DOM and BDOM concentrations in thawing soil. With increasing WFPS, the dominant component of soil DOM changed from humic acid-like substances to fulvic acid-like substances and the biological origin of DOM increased gradually. The protein-like component accounted for 8-20% of soil DOM and was affected by vegetation type and WFPS singly and interactively. The results implied that forest soils with more than 50% WFPS before winter freezing could release large amounts of fulvic acid-like DOM, which would be easily biodegraded and emitted as CO2 or run off with ground water during spring snow thaw.