發(fā)布時間：2018-08-25 17:08

【摘要】：火干擾產(chǎn)生熱能從而誘導土壤有機質的化學氧化,改變碳和氮轉換,對土壤的結構與功能產(chǎn)生嚴重影響,影響程度取決于火強度、火干擾持續(xù)時間和熱滲透。在湖南省株洲市高枧林場選取馬尾松次生林火燒跡地,按兩種土壤、3個溫度和3種土壤水勢進行試驗設計與方差分析,探討火干擾對土壤微生物及氮礦化的影響。結果表明:無機氮的濃度與火強度和初始土壤有機質含量呈正相關關系;火干擾后短期內土壤碳和氮濃度較高,微生物生物量碳和潛在可礦化氮較低,溫度和土壤水勢對基礎呼吸速率沒有顯著影響;當土壤溫度達160℃時,未受火干擾土壤中潛在可礦化氮濃度迅速不穩(wěn)定增加,溫度達350℃時破壞90%的非微生物組織;土壤加熱后水勢對氮礦化過程有顯著影響,水勢越高,潛在可礦化氮損失越大,火干擾土壤的含水量與硝態(tài)氮之間呈正相關關系;培養(yǎng)14d期間,土壤火災歷史、熱處理和土壤水勢對微生物活性、碳和氮礦化有顯著影響,-1.5 MPa水勢下加熱到380℃后兩種土壤的微生物生物量碳含量最高,土壤水勢和可溶性糖呈負相關關系;水勢和火干擾之間的交互作用顯著影響微生物活性和氮轉換,低水勢土壤中的微生物生物量碳、可溶性糖和潛在可礦化氮濃度較高。
[Abstract]:The thermal energy produced by fire can induce the chemical oxidation of soil organic matter and change the conversion of carbon and nitrogen, which has a serious effect on the structure and function of soil. The degree of influence depends on the intensity of fire, the duration of fire disturbance and the heat permeation. In order to study the effect of fire disturbance on soil microorganism and nitrogen mineralization, two soils, three temperatures and three kinds of soil water potential were selected in Gaojian Forest Farm of Zhuzhou City, Hunan Province. The results showed that the concentration of inorganic nitrogen was positively correlated with the intensity of fire and the content of soil organic matter, the concentration of soil carbon and nitrogen was higher and the microbial biomass carbon and potential mineralizable nitrogen were lower in the short term after fire disturbance. When the soil temperature reached 160 鈩，

本文編號：2203550