- 期刊
土壤有機質初始狀態與過度分解現象之關係
The Relationship of Initial Soil Organic Matter and Over Decomposition Phenomenon
摘要
有機質的轉化過程長期以來一直是土壤研究者關心的重點。根據過去的研究，發現一種土壤有機質總量自較高之初始狀態，會因後續之年度添加量不足以維持原有含量時，逐漸降解至一個低含量點，而後又漸漸累積，終至呈一新的穩定態之特殊 ”過度分解” 現象。此現象可能發生在初始狀態含較多易分解之物質。因此植文主要為討模式變數設定及土壤有機質初始狀態與過度分解現象出現之相關性。 根據模式模擬結果顯示：(1)單變數模試因為沒有土壤有機質形態之劃分，未能模擬度分解現象。(2)若模擬初始之易解態與抗分解態植物殘體佔土壤總有機碳之絕大比例，將較易出現過度分解現象，且其變化幅度隨易分解態植物殘體在植物殘體中所佔之比增加而變大。(3)若模擬初始之穩定態有機質佔絕大部分，則不會出現過度分解現象。(4)當土壤有機碳達穩定平衡後，無論添加多少量，都不會出現過度分解現象。
並列摘要
An over decomposition phenomenon was discovered in the simulation process of soil organic matter decomposition. The over decomposition phenomenon presented the special hollow curve of soil organic matter accumulation which decreased temporally to the lower level than initial condition, then gradually increased to thd final equilibrium level. The phenomenon usually happened when easily decomposed portion of initial soil organic carbon was great. This study discussed the relationship of initial soil organic matter and over decomposition phenomenon. The results of simulation process showed that: (1) The over decomposition could not be simulated by the mono-variable model, due to the partitioning of soil organic carbon could not be described by such a model. (2)According to the Jenkinson-Rayner model simulation, the phenomenon could easily occur when initial soil organic carbon contained great decomposable and resistant plant material. The change extent of curve was increased as the decomposable plant material portion was increased. (3) The phenomenon could never occur when the stabilized soil organic matter portion of initial soil organic carbon was great. (4) No matter how much organic matter was added, the phenomenon could never occur after soil organic carbon reached an equilibrium.