【摘要】：為了探究水土漏失過程對巖溶裂隙發(fā)育形態(tài)的響應,采用野外模擬降雨試驗,研究了裂隙出露型巖土(XL)、裂隙埋藏型巖土(XM)兩種結構形態(tài)巖溶裂隙對地下徑流及氮素垂直滲漏的影響,并以全土微區(qū)(QT)為對照。結果表明:裂隙出露型巖土(XL)、裂隙埋藏型巖土(XM)和全土(QT)3個處理中地下徑流對降雨的響應時間表現(xiàn)為XLXMQT,其初始地下徑流產流時間分別是29,77,139min,XL和XM初始地下徑流產流時間分別比QT減少了79.14%,44.60%;降雨產流閾值分別為20.64,55.06,94.90mm,以QT的降雨產流閾值為基準,XL和XM的降雨產流閾值分別減少了78.25%,41.98%;地下徑流達到穩(wěn)定的時間分別為59,107,169min,穩(wěn)定徑流速率分別為42.09,42.36,38.24mm/h。不同結構形態(tài)巖溶裂隙下XL全氮、硝態(tài)氮滲漏濃度最高,濃度均值分別為11.64,10.45mg/L,除XM外,XL、QT在降雨結束前地下徑流中的全氮、硝態(tài)氮濃度基本達到穩(wěn)定;不同結構形態(tài)巖溶裂隙下全氮滲漏量表現(xiàn)為XLXMQT,硝態(tài)氮滲漏量表現(xiàn)為XMXLQT,地下徑流中氮素輸出的主要形式為硝態(tài)氮,其比例約占全氮滲漏量的82.32%~90.12%,而銨態(tài)氮滲漏量占全氮滲漏量的比例不足2%。裂隙的存在,尤其是出露地表裂隙的存在,增加了微區(qū)底部單位面積土壤地下徑流速率,同時還增加了微區(qū)底部單位面積土壤氮素滲漏量,喀斯特地區(qū)普遍存在的裂隙結構促進了水分入滲,加劇了地下徑流中氮素的滲漏。本研究相關結果可為喀斯特地區(qū)水土漏失機制的探索以及物質遷移模型的構建提供科學依據(jù)。
[Abstract]:In order to investigate the response of soil and water loss process to karst fissure development, field simulated rainfall experiment was used. The effects of karst fissures on underground runoff and vertical leakage of nitrogen in two structural forms of (XL), fractured rock and soil (XM) are studied and compared with (QT) in whole soil microarea. The results show that the response time of underground runoff to rainfall in the three treatments of (XL), buried (XM) and (QT) is XLXMQT,. The initial groundwater runoff generation time is 297139min XL and XM initial groundwater runoff respectively. The rainfall runoff threshold of XL and XM was reduced by 79.14 and 44.60 mm, respectively, and the threshold value of rainfall runoff was 20.64 ~ 55.06 ~ 94.90 mm, respectively, and that of XL and XM was reduced by 78.25 ~ 41.98 mm / h, respectively, and the time of stabilization of underground runoff was 5910 7169 min and the steady runoff rate was 42.36 mm / h and 38.24 mm / h respectively. Under different structural forms of karst fissures, the XL total nitrogen concentration is the highest, the mean concentration of nitrate nitrogen is 11.64 ~ 10.45 mg / L, respectively. Except for XM, the total nitrogen concentration of XL,QT in underground runoff before the end of rainfall is basically stable. The total nitrogen leakage under different structural forms of karst fissures shows that the leakage of XLXMQT, nitrate nitrogen is the main form of nitrogen output in underground runoff of XMXLQT, and the main form is nitrate nitrogen. Its proportion is about 82.32% of total nitrogen leakage, while the proportion of ammonium nitrogen leakage to total nitrogen leakage is less than 2%. The existence of fissures, especially in exposed surface cracks, increases the rate of soil underground runoff per unit area at the bottom of the microzone, and also increases the amount of soil nitrogen leakage per unit area at the bottom of the micro-area. The crack structure in karst area promotes the infiltration of water and increases the leakage of nitrogen in underground runoff. The results of this study can provide scientific basis for the exploration of soil and water loss mechanism and the construction of material migration model in karst area.
【作者單位】： 中國科學院亞熱帶農業(yè)生態(tài)研究所亞熱帶農業(yè)生態(tài)過程重點實驗室;中國科學院環(huán)江喀斯特生態(tài)系統(tǒng)觀測研究站;中國科學院大學;
【基金】：國家重點基礎研究發(fā)展計劃項目(2015CB452703) 國家重點研發(fā)計劃項目(2016YFC0502403) 國家自然科學基金項目(41671287)
【分類號】：S157.1

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