http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Elena Armenise (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Soil seal development under simulated rainfall: Structural, physical and hydrological dynamics
Armenise, Elena,Simmons, Robert W.,Ahn, Sujung,Garbout, Amin,Doerr, Stefan H.,Mooney, Sacha J.,Sturrock, Craig J.,Ritz, Karl Elsevier 2018 Journal of hydrology Vol.556 No.-
<P><B>Abstract</B></P> <P>This study delivers new insights into rainfall-induced seal formation through a novel approach in the use of X-ray Computed Tomography (CT). Up to now seal and crust thickness have been directly quantified mainly through visual examination of sealed/crusted surfaces, and there has been no quantitative method to estimate this important property. X-ray CT images were quantitatively analysed to derive formal measures of seal and crust thickness. A factorial experiment was established in the laboratory using open-topped microcosms packed with soil. The factors investigated were soil type (three soils: silty clay loam – ZCL, sandy silt loam – SZL, sandy loam – SL) and rainfall duration (2–14 min). Surface seal formation was induced by applying artificial rainfall events, characterised by variable duration, but constant kinetic energy, intensity, and raindrop size distribution. Soil porosities derived from CT scans were used to quantify the thickness of the rainfall-induced surface seals and reveal temporal seal micro-morphological variations with increasing rainfall duration. In addition, the water repellency and infiltration dynamics of the developing seals were investigated by measuring water drop penetration time (WDPT) and unsaturated hydraulic conductivity (K<SUB>un</SUB>). The range of seal thicknesses detected varied from 0.6 to 5.4 mm. Soil textural characteristics and OM content played a central role in the development of rainfall-induced seals, with coarser soil particles and lower OM content resulting in thicker seals. Two different trends in soil porosity vs. depth were identified: <I>i</I>) for SL soil porosity was lowest at the immediate soil surface, it then increased constantly with depth till the median porosity of undisturbed soil was equalled; <I>ii</I>) for ZCL and SL the highest reduction in porosity, as compared to the median porosity of undisturbed soil, was observed in a well-defined zone of maximum porosity reduction c. 0.24–0.48 mm below the soil surface. This contrasting behaviour was related to different dynamics and processes of seal formation which depended on the soil properties. The impact of rainfall-induced surface sealing on the hydrological behaviour of soil (as represented by WDTP and K<SUB>un</SUB>) was rapid and substantial: an average 60% reduction in K<SUB>un</SUB> occurred for all soils between 2 and 9 min rainfall, and water repellent surfaces were identified for SZL and ZCL. This highlights that the condition of the immediate surface of agricultural soils involving rainfall-induced structural seals has a strong impact in the overall ability of soil to function as water reservoir.</P> <P><B>Highlights</B></P> <P> <UL> <LI> X-ray CT was effectively used to quantify soil seal/crust thickness. </LI> <LI> Different micro-morphological zones within seal layers were revealed. </LI> <LI> Rainfall had a strong and rapid impact on water transport and retention in soil. </LI> <LI> The existence of a soil-dependent raindrop impact threshold was hypothesized. </LI> </UL> </P>
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
