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Changes in SOC and Nutrients under Intensive Tillage in Two Types of Slope Landscapes

Journal of mountain Science 2012年第1期9卷 67-76页

作者： LI Fucheng ZHANG Jianhui SU Zhengan institute of mountain hazards and environment Chinese Academy of SciencesChengdu 610041China The Graduate School of the chinese academy of sciences Beifing 100049China Key Laboratory of mountain hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610041China

The net effect of tillage erosion on soil properties would be associated with the spatial variation in soil constituents,and therefore plays an important role in ecological *** conducted a consecutive tillage by hoeing 15 times during a period with no rainfall in the two slope landscapes(a linear slope and complex slope) of the Yangtze Three Gorges reservoir areas,to examine the relationship between soil erosion rates and the variations in soil chemical properties and compare the effects of soil redistribution on SOC and nutrients between the linear and complex *** the simulated tillage,notable changes in 137 Cs inventories of the soil occurred in the summit and toeslope positions on the linear slope,while there were significant changes in 137 Cs inventories at convex and concave positions on the complex *** profile disappeared at the summit slope boundary,with the exposure area of 16.0% and 7.6% of the experimental plot,respectively,for the linear and complex slopes due to no soil *** organic C and nutrients were completely depleted with the disappearance of soil profiles at soil eroding zones,whereas a remarkable increase in SOC,total N and available nutrient concentrations of the post-tillage surface soil and a decrease in total nutrient concentrations(P and K) were found at depositional zones on the linear *** the complex slope,however,changes in SOC and nutrient concentrations of the post-tillage surface soil exhibited a patterndifferent from that on the linear slope,which showed a remarkable decrease in SOC and total nutrient concentrations but a slight increase in available nutrient concentrations after tillage in the toeslope *** to the gradual increase in soil depth from top to bottom of the slope,SOC and nutrient inventories in the soil profiles were significantly correlated with soil redistribution rates on both the linear and complex *** causes remarkable changes of soil chemical propertie

关键词： SOC Soil chemical property Complex slope Tillage erosion Three Gorges reservoir area

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The runoff characteristics under simulated rainfall on purple soil sloping cropland

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chinese Journal Of Geochemistry 2011年第3期30卷 317-322页

作者： XU Pei FU Bin Key Laboratory of mountain Surface Process and hazards Chinese Academy of Sciences Chengdu 610041 China institute of mountain hazards and environment Chinese Academy of Sciences Chengdu 610041 China

Rainfall runoff is a critical hydrological process related to soil erosion and agricultural non-point pollu-tion. In this study, 25 simulation experiments on rainfall were carried out in five runoff plots. Rape (Brassica campestris) was planted on the downslope of the plots. Experiments were conducted when the vegetation coverage reached 80%. Each plot was subjected to five rainfall events differing in intensity. The results showed: (1) the runoff coefficients of overland flow and subsurface flow were less than 0.6 and 0.005, respectively; (2) the discharge of overland flow was the quadratic function of time; (3) runoff coefficient was the function of slope gradient and rain-fall intensity. When the slope gradient increased from 8.7% to 46.6%, the runoff coefficient of overland flow first increased and then decreased. The runoff coefficient reached the maximum when the slope gradient was within the range of 17.6%-36.4%; and (4) the process of subsurface flow generation included the increasing phase and reces-sion phase. Discharge was a logarithm function of time in the increasing phase, and an exponential function in the recession phase. Runoff coefficient of subsurface flow decreased first and then increased when the slope gradient varied from 8.7% to 46.6% and was not correlated with rainfall intensity.

关键词：模拟降雨径流特性紫色土坡耕地农业非点源污染径流系数降雨强度径流小区

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Variation in carbon,nitrogen and phosphorus partitioning between above-and belowground biomass along a precipitation gradient at Tibetan Plateau

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Journal of mountain Science 2016年第4期13卷 661-671页

作者： HONG Jiang-tao WANG Xiao-dan WU Jian-bo institute of mountain hazards and environment Academy of Sciences of SciencesChengdu 610041China University of chinese academy of sciences Beijing 100049China

Precipitation is a potential factor that significantly affects plant nutrient pools by influencing biomass sizes and nutrient concentrations. However, few studies have explicitly dissected carbon(C), nitrogen(N) and phosphorus(P) pools between above- and belowground biomass at the community level along a precipitation gradient. We conducted a transect(approx. 1300 km long) study of Stipa purpurea community in alpine steppe on the Tibet Plateau of china to test the variation of N pool of aboveground biomass/N pool of belowground biomass(AB/BB N) and P pool of aboveground biomass/P pool of belowground biomass(AB/BB P) along a precipitation gradient. The proportion of aboveground biomass decreased significantly from mesic to drier sites. Along the belt transect, the plant N concentration was relatively stable; thus, AB/BB N increased with moisture due to the major influences by above- and belowground biomass allocation. However, P concentration of aboveground biomass decreased significantly with increasing precipitation and AB/BB P did not vary with aridity because of the offset effect of the P concentration and biomass allocation. Precipitation gradients do decouple the N and P pool of a S. purpurea community along a precipitation gradient in alpine steppe. The decreasing of N:P in aboveground biomass in drier regions may indicate much stronger N limitation in more arid area.

关键词： Biomass allocation Nutrient concentration Qinghai-Tibetan Plateau Alpine steppe Stipa purpurea

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Prediction of Debris-flow Danger Area by Combining Hydrological and Inundation Simulation Methods

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Journal of mountain Science 2011年第1期8卷 1-9页

作者： CUI Peng Key Laboratory of mountain hazards and Earth Surface Process Chinese Academy of Sciences Chengdu 610041 China institute of mountain hazards and environment Chinese Academy of Sciences Chengdu 610041 China Graduate School of chinese academy of sciences Beijing 100049 China

Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2oo8. Debris flow mitigation and risk assessment is a key issue for reconstruction. The existing methods of inundation simulation are based on historical disasters and have no power of prediction. The rain- flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper, the process of water flow was studied by using the Arc-SCS model combined with hydraulic method, and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS. The peak discharge and runoff duration served as input of inundation simulation. Then, the dangerous area is predicted using kinematic wave method and Manning equation. Taking the debris flow in Huashiban gully in Beichuan County, Sichuan Province, china on 24 Sep. 2oo8 as example, the peak discharge of water flow and debris flow were calculated as 35.52 m3·s-1 and 215.66 m3·s-, with error of 4.15% compared to the measured values. The simulated area of debris-flow deposition was 161,500 m2, vs. the measured area of 144,097 m2, in error of 81.75%. The simulated maximum depth was 12.3 m, consistent with the real maximum depth between lO and 15 m according to the field survey. The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration. The present methodology can be applied to predict debrisflow magnitude and evaluate its risk in other watersheds inthe earthquake area.

关键词： Debris flow Arc-SCS model Inundation simulation Risk analysis Wenchuan earthquake

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Simulating Carbon Sequestration and GHGs Emissions in Abies fabric Forest on the Gongga mountains Using a Biogeochemical Process Model Forest-DNDC

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Journal of mountain Science 2008年第3期5卷 249-256页

作者： LU Xuyang CHENG Genwei XIAO Feipeng HUO Changfu institute of mountain hazards and environment Chinese Academy of Sciences Chengdu 610041 China Graduate University of the chinese academy of sciences Beijing 100049 China

The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs （greenhouse gases） fluxes （CO2, NO and N2O） in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production （GPP） of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production （NPP） was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production （NEP） was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.

关键词： Carbon sequestration Forest-DNDC GHGs Abiesfabric forest Gongga mountains

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Assessment of the Performance of WEPP in Purple Soil Area with Simulated Rainfall Experiments

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Journal of mountain Science 2012年第4期9卷 570-579页

作者： FU Bin WANG Yukuan XU Pei YAN Kun Key Laboratory of mountain hazards and Earth Surface Process ChineseAcademy of SciencesChengdu 610041China institute of mountain hazards and environment Chinese Academy of SciencesChengdu 610041China

The water erosion prediction project （WEPP） model is a popular water erosion prediction tool developed on the basis of the physical processes of water erosion. Although WEPP has been widely used around the world, its application in china is still insufficient. In this study, the performance of WEPP used to estimate the runoff and soil loss on purple soil （Calcaric Regosols in FAO taxonomy） sloping cropland was assessed with the data from runoff plots under simulated rainfall conditions. Based on measured soil properties, runoff and erosion parameters, namely effective hydraulic conductivity, inter-rill erodibility, rill erodibility, and critical shear stress were determined to be 2.68 mm h-1, 5.54 x l0^6 kg s-1 m-4, 0.027 s m-1 and 3-5 Pa, respectively, by using the recommended equations in the WEPP user manual. The simulated results were not good due to the low Nash efficiency of 0.41 for runoff and negative Nash efficiency for soil loss. After the four parameters were calibrated, WEPP performed better for soil loss prediction with a Nash efficiency of 0.76. The different results indicated that the equations recommended by WEPP to calculate parameters such as erodiblity and critical shear stress are not suitable for the purple soil areas, Sichuan Province, china. Although the predicted results can be accepted by optimizing the runoff and erosion parameters, more research related to the determination of erodibility and critical sheer stress must be conducted to improve the application of WEPP in the purple soil areas.

关键词： WEPP Soil erosion Simulated rainfall Purple soil Erodibility

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Empirical-Statistical Models Based on Remote Sensing for Estimating the Volume of Landslides Induced by the Wenchuan Earthquake

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Journal of mountain Science 2011年第5期8卷 711-717页

作者： FAN Jianrong LI Xiuzhen GUO Fenfen GUO Xiang Key Laboratory of mountain hazards and Earth Surface Processes Chinese Academy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment CAS Chengdu 610041 China

The Wenchuan Ms 8.0 earthquake on May 12, 2008 induced a huge number of landslides. The distribution and volume of the landslides are very important for assessing risks and understanding the landslide - debris flow - barrier lake - bursts flood disaster chain. The number and the area of landslides in a wide region can be easily obtained by remote sensing technique, while the volume is relatively difficult to obtain because it requires some detailed geometric information of slope failure surface and sub-surface. Different empirical models for estimating landslide volume were discussed based on the data of 107 landslides in the earthquake-stricken area. The volume data of these landslides were collected by field survey. Their areas were obtained by interpreting remote sensing images while their apparent friction coefficients and height were extracted from the images unifying DEM (digital elevation model). By analyzing the relationships between the volume and the area, apparent friction coefficients, and the height, two models were established, one for the adaptation of a magnitude scale landslide events in a wide range of region, another for the adaptation in a small scope. The correlation coefficients (R2) are 0.7977 and 0.8913, respectively. The results estimated by the two models agree well with the measurement data.

关键词： 5.12 Wenchuan earthquake Landslides Remote sensing Volume Estimation model

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Residents'Satisfaction with Public Services in mountainous Areas:An Empirical Study of Southwestern Sichuan Province,china

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chinese Geographical Science 2017年第2期27卷 311-324页

作者： SONG Xueqian DENG Wei LIU Ying ZHAO Chen WAN Jiangjun chengdu University of Information Technology Chengdu 610225China institute of mountain hazards and environment Chinese Academy of SciencesChengdu 610041China

Abstract： Enhancing the efficiency of public services is essential to residents in mountainous areas. It is also important to promote sus- tainable development of these regions. Analysing residents＇ satisfaction with public services in mountainous areas can help in evaluating outcomes of fiscal investment and identifying potential coping approaches for improving public service efficiencies. The residents＇ satisfaction with public services and the factors that influence such satisfaction were examined in this study. A study of 12 towns located in the southwestern Sichuan Province was performed using an entropy-weighted analytic hierarchy process （EWAHP）, the technique for order preference by similarity to ideal solution （TOPSIS） and Tobit regression methods. The results indicate that： 1） the spatial distribu- tion of satisfaction with public services is non-uniform, and the spatial distribution structure varies for different types of public services. 2） Residents＇ satisfaction with public services is influenced by both objective and subjective factors. Population density, economic dis- tance, social and cultural divisions and elevation are the major objective factors, whereas bounded rationality, the hierarchy of needs and service expectations are the main subjective factors. The most effective strategies for enhancing residents＇ satisfaction with public ser- vices are likely to be clustering the population, choosing supply centres with different public services, regulating the cultural division in ethnic minority towns, selecting supply priorities in accordance with residents＇ needs, implementing targeted intervention policies and establishing ＇bottom-up＇ and ＇top-down＇ integrated decision-making mechanisms. Keywords： mountainous areas; public services; residents＇ satisfaction; entropy-weighted analytic hierarchy process （EWAHP）; technique for order preference by similarity to ideal solution （TOPSIS）; Tobit regression; southwestern Sichuan Province

关键词： mountainous areas public services residents' satisfaction entropy-weighted analytic hierarchy process (EWAHP) technique for order preference by similarity to ideal solution (TOPSIS) Tobit regression southwestern Sichuan Province

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Effects of Contour Hedgerow Intercropping on Nutrient Losses from the Sloping Farmland in the Three Gorges Area,china

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Journal of mountain Science 2012年第1期9卷 105-114页

作者： WANG Tao ZHU Bo XIA Lizhong Key Laboratory of mountain environment Evolvement and Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China institute of Soil Science Chinese Academy of SciencesNanjing 210008China

Eutrophication is recognized as one of the major environmental problems in the Three Gorges *** hedgerows have been used as a major soil and water conservation measure in this ***,a two-year study was conducted to investigate the effects of contour hedgerow intercropping on nutrient loss from sloping farmland in this *** treatments were applied:(1) Maize + Soybean,(2) Maize,(3) Maize + Alfalfa,and(4) Maize + Hemerocallis citrina *** indicated that nutrient loss in the control treatment(Maize) was serious,especially the average loss flux of total nitrogen(2245.8 mg) and total phosphate(2434.2 mg) in a typical rainfall ***,the nutrient losses by runoff in the other three treatments with contour hedgerow intercropping showed significant *** with the control treatment,the total nitrogen loss in the Alfalfa and Hemerocallis citrina Baroni decreased by 80.9% and 85.0%,respectively,and the total phosphorus loss in the two treatments decreased by 91.2% and 92.5%,***,it is concluded that nutrient losses could be reduced by using contour hedgerows in the Three Gorges *** runoff volume and sediment loss was the main mechanisms of contour hedgerow intercropping to reduce nutrient loss.

关键词： Contour hedgerow Sloping farmland Nitrogen Phosphorus Three Gorges Reservoir china

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Land cover change in different altitudes of Guizhou-Guangxi karst mountain area, china： patterns and drivers

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Journal of mountain Science 2017年第9期14卷 1873-1888页

作者： CHEN Tian-tian PENG Li LIU Shao-quan WANG Qiang institute of mountain hazards and environment Chinese Academy of Sciences Chengdu 610041 China University of chinese academy of sciences Beijing 100049 China chengdu University of Technology Chengdu 610059 China

Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality and regional ecological environment. Therefore, the gradient relationship analysis between land cover changes and altitude is very important for regional sustainability. This study investigated land cover dynamics based on land cover data from a typical mountainous area in the Guizhou-Guangxi karst mountain area, china, in 2000 and 2010, then explored the relationship between altitude and land cover change and analyzed different drivers of land cover change at different altitudes. Our findings are as follows. 1) From 2000 to 2010, the total area of land cover transition was 7167.04 km^2 or 2.8% of the region. The increasing area of build-up land(926.23 km^2) was larger than that of forest(859.38 km^2), suggesting that the urban construction speed was higher than that of reforestation. 2) Intensity of land cover transition in northwestern Guizhou-Guangxi karst mountain area was much larger than that of southeast part and their transition trend was also significantly different, which was consistent with regional population and economy. 3) Human activity was the most dramatic at altitudes between 0–500 m. For 500–1000 m, grassland mainly converted to forest and build-up land. Area of land cover transition was the greatest between 1000–1500 m, while above 1500 m, the transition of grassland was the most obvious. 4) The drivers of land cover change varied. Land cover change was positively correlated with gross domestic product and population density but was inversely related to relief amplitude. There were correlations between land cover change and distance to roads and rivers, and their correlations varied with altitude. By revealing patterns and causes of land cover changes in different altitudes, we hope to understand the vertical dependence of land cover c

关键词： Land cover change Vertical difference Drivers Regional sustainability Guizhou-Guangxi karst mountain area

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