Stability analysis of an unsaturated soil slope considering rainfall infiltration based on the Green-Ampt model

Based on the principle of saturated infiltration and the Green-Ampt model, an unsaturated infiltration model for a soil slope surface was established for either constant moisture content, or depth-varying moisture content and the slope. Infiltration parameters in the partially saturated slope were revealed under sustained rainfall. Through analysis of the variation of initial moisture content in the slope, the ponding time, infiltration depth, and infiltration rate were deduced for an unsaturated soil slope subject to rainfall infiltration. There is no ponded water on the surface of the slope under sustained low-intensity rainfall. The results show that the infiltration parameters of an unsaturated slope are influenced by the initial moisture content and the wetting front saturation, the soil cohesion and rainfall intensity under sustained rainfall. More short-term slope failures can occur with the decrease of cohesion of the soil of the slope. The ponding time and infiltration depth differ considering constant or different initial moisture content respectively in the soil slope. Then, best-fit curves of the infiltration rate, ponding time, and infiltration depth to the wetting front saturation were obtained with constant or different initial moisture contents. And the slope failure time is roughly uniform when subject to a rainfall intensity I5 mm/h.     

Responses of soil moisture to vegetation restoration type and slope length on the loess hillslope

Soil moisture, a critical variable in the hydrologic cycle, is highly influenced by vegetation restoration type. However, the relationship between spatial variation of soil moisture, vegetation restoration type and slope length is controversial. Therefore, soil moisture across soil layers (0-400 cm depth) was measured before and after the rainy season in severe drought (2015) and normal hydrological year (2016) in three vegetation restoration areas (artificial forestland, natural forestland and grassland), on the hillslopes of the Caijiachuan Catchment in the Loess area, China. The results showed that artificial forestland had the lowest soil moisture and most severe water deficit in 100-200 cm soil layers. Water depletion was higher in artificial and natural forestlands than in natural grassland. Moreover, soil moisture in the shallow soil layers (0-100 cm) under the three vegetation restoration types did not significantly vary with slope length, but a significant increase with slope length was observed in deep soil layers (below 100 cm). In 2015, a severe drought hydrological year, higher water depletion was observed at lower slope positions under three vegetation restoration types due to higher transpiration and evapotranspiration and unlikely recharge from upslope runoff. However, in 2016, a normal hydrological year, there was lower water depletion, even infiltration recharge at lower slope positions, indicating receiving a large amount of water from upslope. Vegetation restoration type, precipitation, slope length and soil depth during a rainy season, in descending order of influence, had significant effects on soil moisture. Generally, natural grassland is more beneficial for vegetation restoration than natural and artificial forestlands, and the results can provide useful information for understanding hydrological processes and improving vegetation restoration practices on the Loess Plateau     

Deep profile soil moisture distribution characteristics for different microtopographies on the semi-arid Loess Plateau,China

Soil moisture is a limiting factor for vegetation restoration on the Loess Plateau, China. Micro-topography may cause heterogeneities in the distribution of soil moisture, but little is known about its effect on deep soil moisture. Our study aims to explore the distribution and impact of soil moisture within the upper 10 m of soil for different microtopographies. Taking undisturbed slope as the control, five micro-topographies were selected. Soil moisture over a depth of 0-10 m from 2017 to 2019 was investigated, and soil particle size and soil organic matter were measured. Variance analysis and multiple comparisons were used to analyze the difference in soil moisture for different microtopographies and multiple-linear regression was used to analyze the influence of micro-topography on soil moisture. There are significant differences in soil moisture within the different layers underlying the examined micro-topographies, while the inter-annual variation in soil water storage for the selected microtopographies increase with increased rainfall. The depth of influence of micro-topographic vegetation on soil moisture exceeded 1000 cm for a gully(GU), 740 cm for a sink hole(SH), 480 cm for a scarp(SC), 360 cm for an ephemeral gully(EG) and 220 cm for a platform(PL). Micro-topography will cause the heterogeneous distribution of soil moisture in the shallower layers, which changes the vegetation distribution differences between micro-topographies. This may be the survival strategy of herbaceous vegetation in response to climate change in the Loess Plateau. For future vegetation restoration efforts, we need to pay attention to the influence of microtopography on soil moisture.     

中国北方农牧交错带土地沙化区典型植物的雨季水分来源

中国北方农牧交错带是中东部地区重要的生态安全屏障, 由于其系统结构脆弱、生态环境问题多发、土地沙化严重, 开展生态修复工作显得十分重要。植物-土壤水分关系作为土地沙化区生态水文过程的重要组成部分, 研究二者的转化过程对于了解植物吸水模式、确定生态修复的首选植物种非常关键。以河北省张家口市康保县北部为例, 基于雨季的大气降水、地下水、土壤水和植物水的氢氧同位素特征, 分析了主要植物的吸水层位、生态位宽度和水分竞争关系。结果表明, 柠条以吸收80~100 cm深度土壤水为主, 吸水比例最大可达87.7%, 油菜花以吸收0~20 cm深度土壤水为主, 吸水比例最大可达82.3%, 狼针的吸水层位与土壤含水率有关, 在含水率较高的深度吸水比例更大, 栉叶蒿的吸水深度较为均衡, 各植物种的生态位宽度均较大, 但部分植物间存在较强的水分竞争关系。本研究为中国北方农牧交错带土地沙化区的植物水源来源识别和生态修复提供了科学依据。      

Seasonal variations in the influence of vegetation cover on soil water on the loess hillslope

Soil water is the key factor that restricts the restoration of the local ecological systems in the Loess Plateau of China. Studying the effects of vegetation types on soil water and its seasonal variation helps to understand hydrological characteristics and provides insights into the sustainable restoration of vegetation. Therefore, the Caijiachuan watershed was chosen as the research object to investigate the water status of a 0-10 m soil layer under different vegetation types including Pinus tabulaeformis, Robinia pseudoacacia, Platycladus orientalis, apple orchard, natural forestland,farmland and grassland. By comparing the difference between soil water of different land use types and that of grassland during the same period, the seasonal changes of soil water status of different types were judged. The results show that(1) in the 0-10 m soil layer, the largest value of soil water content was in the0.3-0.4 m layer, and the lowest was in the 5.6-5.8 m layer. The depths at which the vegetation cover influenced the soil water were up to 10 m;(2) among summer, fall and spring, the soil water storage wasthe highest in the fall. In addition, the lowest value of relative accumulation was in the fall, which was the period in which the soil water recovered;(3) the soil water in the 0-10 m layer was in a relatively deficient state in the artificial forestlands, apple orchards and native forestlands, while the relative accumulation was in the farmland. In addition, the relative deep soil layers(8-10 m) had more serious deficits in the areas in which P. tabulaeformis, R. pseudoacacia and the apple orchard grew;(4) during the study period, the farmland in the summer had the largest relative accumulation(182.71 mm), and the land under R.pseudoacacia in the fall had the lowest relative deficit(512.20 mm). In the Loess Plateau, vegetation cover will affect the change of deep soil moisture and artificial forest will cause soil water loss in different degrees.     

基于洪峰模数的山洪灾害雨量预警指标研究

山洪灾害预警是防御山洪的重要非工程措施,雨量预警指标是山洪灾害预警的关键。目前的雨量预警指标计算方法对水文气象资料条件以及模型建模率定都有很高的要求,并不适用于基层防汛人员。因此,本文基于全国山洪灾害调查评价成果数据,提出了一种运用洪峰模数计算雨量预警指标的简便、易用的方法。该方法以小流域洪水计算推理公式为基础,将公式中流量与流域面积的比值用洪峰模数表示,得到基于洪峰模数的临界雨量估算公式,并考虑流域土壤含水量等因素,分析临界雨量变化阈值,最终得到雨量预警指标。本文以云南省绥江县双河小流域为例,计算结果显示不同时段（1 h、3 h、6 h）净雨量和预警时段呈线性关系。降雨损失计算中洼地蓄水和植被截留在不同时段相同,土壤下渗在不同的时段不相同。在此基础上,计算不同土壤含水量条件下,不同时段的雨量预警指标。最后,对临界流量、降雨损失和预警指标进行了合理性分析,结果显示预警指标和调查评价结果及实测降雨都比较接近,计算的预警指标合理。本研究为基层山洪灾害预警提供了一种快速、便捷的预警指标计算方法,为预警指标计算提供技术支持。     

Vertical distribution of soil nematode communities under different tillage systems in lower reaches of Liaohe River

Vertical distribution of soil nematode communities under conventional tillage (CT),no-tillage (NT) and fallow field (FF) treatments in the Lower Reaches of the Liaohe River was investigated at six soil depths (0-5 cm,5-15 cm,15-30 cm,30-50 cm,50-75 cm and 75-100 cm). The results show that total nematode abundance gradually decreases with depth,and the highest number of total nematodes is observed at 0-5 cm depth under NT and FF treatments. The number of fungivores and plant parasites is significantly higher...     

大柳塔采煤塌陷区土壤含水量的空间变异特征分析

通过研究采煤塌陷区土壤水空间分布及动态变化特征,查明了采煤塌陷对土壤含水量的影响,这对矿区生态环境保护、塌陷区土地复垦等具有重要指导意义。以大柳塔双沟采煤塌陷区为试验区,利用传统统计学和地统计学方法分析了采煤塌陷条件下的包气带土壤水空间变异特征。研究结果表明:由于采煤塌陷造成塌陷区土壤层位在垂向上倒置、重组,引起土壤粒度、容重、孔隙度等土壤物理特性的改变,使塌陷区土壤含水量比非塌陷区显著降低,在不同深度层（0~60 cm）分别减少14.2%~21.9%;在垂向分布上塌陷区土壤水分也表现出较强的变异性,其离散系数在不同深度（0~60 cm）与非塌陷区的差值在19.2%~50%之间。根据试验区0 cm、20 cm、40 cm、60 cm四个层面土壤含水量的Kriging插值等值线图显示,土壤含水量低值区均位于塌陷区内的塌陷坑部位,证明地表的地裂缝、塌陷坑、塌陷洞等塌陷形态对土壤持水能力的影响颇为显著。采煤塌陷区土壤含水量降低、空间变异性增强直接导致了地表植被生存环境的恶化,地表景观被严重破坏。     

城市扩展对趵突泉泉域直接补给区保泉能力影响

直接补给区是趵突泉泉域重要的补给场所之一,随着城市发展其面积逐渐缩小。通过遥感手段解译60多年来济南城市发展趋势,分析揭示其对直接补给区面积及强渗漏小流域入渗功能的影响,采用大气降雨入渗系数法定量计算直接补给区面积削减对泉水保护的影响。结果表明,1954年—2015年,济南城市发展经历了平缓增长、快速增长、爆发式增长3个发展阶段,导致泉水直接补给区面积累计削减130km^2,约占总面积的29%,直接补给区内强渗漏小流域遭受不同程度破坏,6个渗漏功能完全丧失,9个渗漏功能部分丧失,仅9个渗漏功能保存近似完好,直接造成泉水入渗补给量减少约9.7万m^3/d(以多年平均降雨量648mm计)。直接补给区生态功能亟待保护与修复,应统筹管理小流域内山、水、林、土、草,加强小流域内山坡、山脚、山谷局部水循环的系统保护与修复,逐步恢复泉水补给能力。     

Interpreting sedimentation dynamics at Longxi catchment in the Three Gorges Area,China, using Cs-137 activity,particle size and rainfall erosivity

Reservoir sedimentation dynamics were interpreted using Cs-137 activity,particle size and rainfall erosivity analysis in conjunction with sediment profile coring.Two sediment cores were retrieved from the Changshou reservoir of Chongqing,which was dammed in 1956 at the outlet of Longxi catchment in the Three Gorges Area using a gravity corer equipped with an acrylic tube with an inner diameter of 6 cm.The extracted cores were sectioned at 2 cm intervals.All sediment core samples were dried,sieved(2 mm) and weighed.137 Cs activity was measured by γ-ray spectrometry.The particle size of the core samples was measured using laser particlesize granulometry.Rainfall erosivity was calculated using daily rainfall data from meteorological records and information on soil conservation history was collated to help interpret temporal sedimentation trends.The peak fallout of 137 Cs in 1963 appeared at a depth of 84 cm in core A and 56 cm in core B.The peaks of sand contents were related to the peaks of rainfall erosivity which were recorded in 1982,1989,1998 and 2005,respectively.Sedimentation rates were calculated according to the sediment profile chronological controls of 1956,1963,1982,1989,1998 and 2005.The highest sedimentation rate was around 2.0 cm?a~(-1) between 1982 and 1988 when the Chinese national reform and the Household Responsibility System were implemented,leading to accelerated soil erosion in the Longxi catchment.Since 1990 s,andparticularly since 2005,sedimentation rates clearly decreased,since a number of soil conservation programs have been carried out in the catchment.The combined use of 137 Cs chronology,particle size and rainfall erosivity provided a simple basis for reconstructing reservoir sedimentation dynamics in the context of both physical processes and soil restoration.Its advantages include avoiding the need for full blown sediment yield reconstruction and the concomitant consideration of core correlation and corrections for autochthonous inputs and reservoir trap efficiency.     

Effects of degradation succession of alpine wetland on soil organic carbon and total nitrogen in the Yellow River source zone,west China

Wetland is an important carbon pool,and the degradation of wetlands causes the loss of organic carbon and total nitrogen.This study aims to explore how wetland degradation succession affects soil organic carbon(SOC)and total nitrogen(TN)contents in alpine wetland.A field survey of 180 soilsampling profiles was conducted in an alpine wetland that has been classified into three degradation succession stages.The SOC and TN contents of soil layers from 0 to 200 cm depth were studied,including their distribution characteristics and the relationship between microtopography.The results showed that SOC and TN of different degradation succession gradients followed the ranked order of Non Degradation(ND)>Light Degradation(LD)>Heavy Degradation(HD).SWC was positively correlated with SOC and TN(p<0.05).As the degree of degradation succession worsened,SOC and TN became more sensitive to the SWC.Microtopography was closely related to the degree of wetland degradation succession,SWC,SOC and TN,especially in the topsoil(0-30 cm).This result showed that SWC was an important indicator of SOC/TN in alpine wetland.It is highly recommended to strengthen water injection into the wetland as a means of effective restoration to reverse alpine meadow back to marsh alpine wetland.     

Spatiotemporal Variation of Riverine Nutrients in a Typical Hilly Watershed in Southeast China Using Multivariate Statistics Tools

The water quality of lakes can be degraded by excessive riverine nutrients.Riverine water quality generally varies depending on region and season because of the spatiotemporal variations in natural factors and anthropogenic activities.Monthly water quality measurements of eight water quality variables were analyzed for two years at 16 sites of the Tianmuhu watershed.The variables were examined using hierarchical cluster analysis(HCA) and factor analysis/principal component analysis(FA/PCA) to reveal the spatiotemporal variations in riverine nutrients and to identify their potential sources.HCA revealed three geographical groups and three periods.Two drainages comprising towns and large villages were the most polluted, six drainages comprising widely distributed tea plantations and orchards were moderately polluted, and eight drainages without the factors were the least polluted.The river was most polluted in June when the first heavy rain(daily rainfall 50 mm) occurs after fertilization and the number of rainy days is most(monthly number of rainy days 20 days).Moderate pollution was observed from October to May, during which morethan 60% of the total nitrogen fertilizer and all of the phosphorus fertilizer are applied to the cropland, the total manure is applied to tea plantations and orchards, and a monthly rainfall ranging from 0 mm to 164 mm occurs.The remaining months were characterized by frequent raining(i.e., number of rainy days per month ranged from 5 to 24) and little use of fertilizers, and were thus least polluted.FA/PCA identified that the greatest pollution sources were the runoff from tea plantations and orchards,domestic pollution and the surface runoff from towns and villages, and rural sewage, which had extremely high contributions of riverine nitrogen, phosphorus,and chemical oxygen demand, respectively.The tea plantations and orchards promoted by the agricultural comprehensive development(ACD) were not environmentally friendly.Riverine nitrogen is a major water pollution parameter in hilly watersheds affected by ACD, and this parameter would not be reduced unless its loss load through the runoff from tea plantations and orchards is effectively controlled.     

Effects of vegetation restoration on soil organic carbon in China: A meta-analysis

Vegetation restoration has been proposed as an effective method for increasing both plant biomass and soil carbon(C) stocks. In this study, 204 publications(733 observations) were analyzed, focusing on the effects of vegetation restoration on soil organic carbon(SOC) in China. The results showed that SOC was increased by 45.33%, 24.43%, 30.29% and 27.98% at soil depths of 0–20 cm, 20–40 cm, 40–60 cm and 60 cm after vegetation restoration, respectively. Restoration from both cropland and non-cropland increased the SOC content. The conversion of non-cropland was more efficient in SOC accumulation than the conversion of cropland did, especially in 40 cm layers. In addition, the conversion to planted forest led to greater SOC accumulation than that to other land use did. Conversion period and initial SOC content extended more influence on soil C accumulation as the main factors after vegetation restoration than temperature and precipitation did. The SOC content significantly increased with restoration period after long-term vegetation restoration( 40 yr), indicating a large potential for further accumulation of carbon in the soil, which could mitigate climate change in the near future.     

Root growth dynamics during recovery of tropical mountain forest in North-east India

Ever increasing pressures on tropical forests worldwide due to anthropogenic disturbances have greatly affected both above-and belowground functioning of these forests.While fine roots play major ecological roles in forests through assisting in nutrient and water uptake and returning elements to the soil environment,coarse roots play an important role in C sequestration.We studied changes in fine and coarse root biomass,production,turnover and carbon and nitrogen return to the soil in two regenerating forest stands(RFs)following stonemining that were 5 years(RF-5)and 15 years(RF-15)post-disturbance compared with a natural forest stand(NF)in Mizoram,North-east India.Fine(2mm)and coarse root(2-10 mm)biomass differed significantly among the forest stands and ranged from239(RF-5)to 415(NF)and 230(RF-5)to 436(NF)g m 2,respectively.Total root(fine+coarse)biomass increased during stand development but the proportion of very fine root(0.5 mm)to total root production decreased.Fine root biomass decreased with increasing soil depth.Fine and total root biomass showed strong seasonal correlations with soil moisture,more so than for rainfall and temperature,whereas these relationships were less clear for the coarse root biomass.The amount of N(25-55 kg ha~(-1))and C(1.9-3.6t ha~(-1))stored in root biomass increased with stand age with a corresponding increase in production and turnover of C and N to the soil.Disturbance to these tropical forests negatively affected root dynamics,influenced their spatiotemporal patterns,and reduced the production,amount and availability of nutrients returned to the soil along with a strong reduction in the root biomass carbon pool and sequestration in carbon residence time.We observed that root growth,especially fine roots,is dependent on abiotic variables,and plays a significant role in early stages of secondary succession by adding organic matter and nutrients through high turnover rates in these forests.     

SPATIAL—TEMPORAL VARIATION OF HEAVY METAL ELEMENTS CONTENT IN COVERING SPIL OF RECLAMATION AREA IN FUSHUN COAL MINE

Grid method is employed for sampling covering soil at the test field,which is reclamation area filled by coal mining wastes for cropland in the Fushun coal mine,Liaoning Province,the Northeast China.The soil samples are taken at different locations,including three kinds of covering soil,three different depths of soil layers and four different covering ages of covering soil.The spatial-temporal variation of heavy metal element content in reclamation soil is stud-ied.The results indicate that the content of heavy metal elements is decreasing year after year,the determinant reason why the content of heavy metal elements at 60cm depth layer is higher than that at 30cm depth layer and surface is fertiliz-er and manure application;the metal elements mainly come from external environment;there is no metal pollution coming from mother material (coal mining wastes)in plough layer of covering soil.     

SLOPE LITHOLOGIC PROPERTY, SOIL MOISTURE CONDITION AND REVEGETATION IN DRY-HOT VALLEY OF JINSHA RIVER

1IN T R O D U T IO N The dry-hotvalleyisone of the unique physiographic typesinSouthwest China, which ischaracterizedby its dry and hot climate, Savanna-likevegetationand its sharp contrastwith the surrounding landscape units (ZHANG ,1992 ).The dry-hotval…     

Effects of land cover on soil organic carbon stock in a karst landscape with discontinuous soil distribution

Land cover type is critical for soil organic carbon(SOC) stocks in territorial ecosystems. However, impacts of land cover on SOC stocks in a karst landscape are not fully understood due to discontinuous soil distribution. In this study, considering soil distribution, SOC content and density were investigated along positive successional stages(cropland, plantation, grassland, scrubland, secondary forest, and primary forest) to determine the effects of land cover type on SOC stocks in a subtropical karst area. The proportion of continuous soil on the ground surface under different land cover types ranged between 0.0% and 79.8%. As land cover types changed across the positive successional stages, SOC content in both the 0–20 cm and 20–50 cm soil layers increased significantly. SOC density(SOCD) within 0–100 cm soil depth ranged from 1.45 to 8.72 kg m-2, and increased from secondary forest to primary forest, plantation, grassland, scrubland, and cropland, due to discontinuous soil distribution. Discontinuous soil distribution had a negative effect on SOC stocks, highlighting the necessity for accurate determination of soil distribution in karst areas. Generally, ecological restoration had positive impacts on SOC accumulation in karst areas, but this is a slow process. In the short term, the conversion of croplandto grassland was found to be the most efficient way for SOC sequestration.     

Analyzing forest effects on runoff and sediment production using leaf area index

Quantifying the effects of forests on water and soil conservation helps further understanding of ecological functions and improving vegetation reconstruction in water-eroded areas.Studies on the effects of vegetation on water and soil conservation have generally focused on vegetation types or vegetation horizontal distribution densities.However,only a few studies have used indicators that consider the vegetation vertical distribution.This study used the leaf area index(LAI) to investigate the relationship between forests and water and soil conservation in experimental plots.From 2007 to 2010,rainfall characteristics,LAI,and water and soil loss in 144 natural erosive rainfall events were measured from five pure tree plots(Pinus massoniana).These tree plots were located in Hetian Town,Changting County,Fujian Province,which is a typical water-eroded area in Southern China.Quadratic polynomial regression models for LAI and water/soil conservation effects(RE/SE) were established for each plot.The RE and SE corresponded to the ratios of the runoff depth(RD) and the soil loss(SL) of each pure tree plot to those of the control plot under each rainfall event.The transformation LAIs of the LAI–RE and LAI–SE curves,as well as the rainfall characteristics for the different water/soil conservation effects,were computed.The increasing LAI resulted in descending,descending–ascending,ascending–descending,and ascending trends in the LAI–RE and LAI–SE curves.The rainfall frequencies corresponding to each trend of LAI–RE and LAI–SE were different,and the rainfall distributions were not uniform per year.The effects of soil conservation in the plots were superior to those of water conservation.Most of the RE and SE values presented a positive effect on water and soil conservation.The main factor that caused different effects was rainfall intensity.During heavy rains(e.g.,rainfall erosivity R = 145 MJ mm/ha h and maximum 30 min intensity I30 = 13 mm/h),the main effects were positive,whereas light rains(e.g.,R = 70 MJ mm/ha h and I30 = 8 mm/h) generally led to negative effects.When the rainfall erosivity was lower than that of the positive or the negative effects to a threshold and the tree LAI reached a transformation value,the relationships between LAI and RE or SE notably transformed.Results showed that the plottransformation LAIs for water and soil conservation during rainfall events were both approximately 1.0 in our study.These results could be used to come up with a more efficient way to alleviate water and soil loss in water-eroded areas.     

Effects of tillage management on infiltration and preferential flow in a black soil, Northeast China

The impacts of no-tillage (NT) and moldboard plough (MP) managements on infiltration rate and preferential flow were characterized using a combined technique of double-ring device and dye tracer on a black soil (Mollisols) in Northeast China. The objective of this study is to evaluate how tillage practices enhance soil water infiltration and preferential flow in favor of soil erosion control in the study area. The steady infiltration rates under NT management are 1.6 and 2.1 times as high as those under MP management in the 6th and 8th years of the tillage management in place, while the infiltrated water amounts under NT management are 1.4 and 2.0 times as high as those under MP management, respectively. The depth of methylene blue penetrated into NT soil increases from 43 cm in the 6th year to 57 cm in the 8th year, which are 16 cm and 19 cm deeper than those in MP soil, respectively. The results of morphologic image show that more biological macro-pores occur in NT soil than in MP soil. These macro-pores play a key role in enhancing preferential flow in NT soil, which in turn promotes water infiltration through preferential pathways in NT soil. The results are helpful to policy-making in popularizing NT and have the implications for tillage management in regard to soil erosion control in black soil region of China.     

Field experiment of rainfall infiltration on a soil slope and simulations based on a water-air two-phase flow model

Rainfall infiltration on a soil slope is usually an unsaturated seepage process that can be described by a water-air two-phase flow model. The effect of pore air pressure on rainfall infiltration has been widely recognized and validated by means of numerical simulations and laboratory experiments. However, whether a slope can actually seal pore air continues to be debated by researchers. In this study, a water-air two-phase flow model is used to simulate the rainfall infiltration process on a soil slope, and a field experiment is conducted to realistically test the sealing conditions of a slope. According to the numerical simulation, the areas of water and air flow in and out on the slope surface are relatively stable and can be classified as the "inhalation zone" and "overflow zone", respectively. Intermittent rainfall on the soil slope has an amplifying effect on pore air pressure because rainfall intensity is usually at the millimeter level, and it causes pore air pressure to reach the cm level. A field experiment was performed to determine whether a slope can realistically seal pore air and subsequently verify the regularity of rainfall infiltration. Air pressure sensors were buried in the slope to monitor the pore air pressures during the rainfall process. The monitoring results show that the pore air pressure in the slope changed, which indicates that the slope can seal air. Moreover, the amplification effects of intermittent rainfall on pore air pressure were observed for natural rainfall, which agrees well with the numerical simulation results.