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1.
土壤可蚀性在WEPP模型中的应用 总被引：1，自引：0，他引：1
影响土壤侵蚀过程的关键因素是侵蚀力和土壤可蚀性。土壤可蚀性是定量计算土壤流失的重要指标和土壤侵蚀预报模型中的必要参数。WEPP是由美国农业部开发的新一代水蚀预测模型 ,该模型以土壤可蚀性为必要参数 ,并将其分解为细沟间可蚀性 (Ki)、细沟可蚀性 (Kr)和临界剪切力 (τc)来预报流域径流形成与土壤侵蚀过程 相似文献
2.
小麦秸秆粉碎还田配施氮肥与多酚对土壤侵蚀阻力的影响 总被引：1，自引：1，他引：0
小麦秸秆粉碎还田可改变土壤性质,进而影响土壤侵蚀阻力。以北方土石山区褐土为研究对象,利用L_9(3~4)正交表对秸秆长度(2,5,8 cm)、秸秆还田量(2 000,4 000,8 000 kg/hm~2)、纯氮施加量(100,140,180 kg/hm~2)及纯多酚施加量(0,40,80 kg/hm~2)4因素3水平进行正交设计,加空白对照共计10个处理。采用JET土壤侵蚀阻力测定仪测定土壤可蚀性和临界剪切力,分析秸秆粉碎还田对土壤侵蚀阻力的影响。结果表明:与对照相比,秸秆粉碎还田后各处理土壤临界剪切力均有所增大,但差异不显著(P0.05),氮肥量对土壤临界剪切力影响显著,随氮肥量增加土壤临界剪切力先增加后减小。秸秆长度、还田量、氮肥量和多酚量对土壤可蚀性均具有显著影响,其中秸秆还田量和多酚量的影响贡献率较大,分别为50.61%和23.84%,其影响分别为负效应和正效应。秸秆粉碎还田条件下,土壤可蚀性可用土壤饱和含水量、0.25 mm团聚体含量进行线性拟合(R~2=0.81,P0.01);0.25 mm水稳性团聚体含量与土壤可蚀性能较好地模拟土壤临界剪切力(R~2=0.76,P0.05)。研究结果有助于理解秸秆粉碎还田后土壤侵蚀阻力变化与机制,并可为模型模拟提供数据支持。 相似文献
3.
冻融循环和土壤性质对东北黑土抗剪强度的影响 总被引：3，自引：3，他引：0
为了揭示东北黑土区季节性冻融循环作用和土壤性质对土壤可蚀性的影响,采集黑龙江省宾县典型薄层黑土区(BX)和克山县典型厚层黑土区(KS)0—20cm的耕层土壤,通过室内冻融循环模拟和土壤直剪试验,分析了冻融作用和土壤性质对土壤抗剪强度的影响。结果表明:(1)经历1次冻融作用后BX和KS 2种供试土壤抗剪强度分别减小3.9%和9.2%,二者黏聚力分别减小15.2%和29.4%,内摩擦角分别减小1.4%和3.6%。经历7次冻融作用后,BX和KS2种供试土壤抗剪强度分别减小9.1%和15.1%,土壤黏聚力分别减小40.7%和74.5%,土壤容重分别减小6.7%和9.2%。受土壤有机质、水稳性团聚体、黏粒含量等的影响,KS土壤抗剪强度、黏聚力、内摩擦角和土壤容重的减小幅度皆大于BX供试土壤。(2)2种供试土壤抗剪强度皆随冻融循环次数的增加呈先逐渐减小后趋于稳定的变化趋势;第1次冻融循环对土壤抗剪强度破坏最大,经历1次冻融循环后2种土壤抗剪强度和黏聚力的减小量分别占7次冻融循环土壤抗剪强度和黏聚力总减小量的43.4%和61.0%,37.3%和39.4%。(3)土壤抗剪强度与土壤容重和团聚体平均重量直径(MWD)呈极显著的正相关,而与冻融循环次数呈极显著的负相关。 相似文献
4.
三峡库区生物结皮对土壤分离过程的影响及其机制 总被引：2，自引：0，他引：2
为探明三峡库区生物结皮对土壤分离过程的影响及机制,以湖北省秭归县王家桥小流域为研究区域,选取以苔藓为优势种的生物结皮样地,以无结皮覆盖的裸地为对照,设计5个结皮盖度水平(1%～20%、20%～40%、40%～60%、60%～80%和80%～100%),采集原状土样,进行不同侵蚀动力条件下(水流剪切力4.89～17.99 Pa)的冲刷试验,建立生物结皮盖度与土壤分离能力、细沟可蚀性和临界剪切力间的定量关系,明确影响土壤分离过程的主要因素并阐明其作用过程。结果表明,生物结皮盖度显著影响土壤分离,裸地的土壤分离能力(0.160 kg/(m2·s))为生物结皮土壤(0.008～0.081 kg/(m2·s))的1.9倍～21.0倍,裸地的细沟可蚀性(0.018 7 s/m)为生物结皮土壤(0.009 5～0.000 9 s/m)的2.0倍～20.0倍;相对土壤分离速率和细沟可蚀性均随结皮盖度的增加呈指数衰减;通径分析显示土壤分离能力主要受结皮盖度、土壤黏结力和沙粒含量的影响,细沟可蚀性主要受结皮盖度和土壤容重的影响;非线性回归表明,土壤分离能力可用水流剪切力、黏结力和结皮盖度的幂函数进行模拟(NSE=0.947)。综上,三峡库区生物结皮的发育有效增强了土壤侵蚀阻力,其抑制土壤分离主要通过地表覆盖的直接保护作用和土壤属性的间接改变作用。 相似文献
5.
水力梯度影响下WEPP模型估计细沟侵蚀参数的可行性分析 总被引：2，自引：0，他引：2
为分析近地表水文条件影响下WEPP(Water Erosion Prediction Project)模型估计细沟可蚀性和临界剪切力的可行性,该研究选取长江中上游地区典型黄壤为研究对象,采用不同水力梯度值模拟饱和/渗流(水力梯度为0、0.71和1.43 m/m)和排水(水力梯度为?0.71和?1.43 m/m)2种近地表水文条件,并设置3个放水流量(0.55、1.58、2.51 L/min),利用"V"形试验土槽测定不同条件下细沟产流产沙,以WEPP模型估算的土壤可蚀性和临界剪切力为计算值。测定增大流量直到侵蚀开始并出现连续不断的土壤颗粒分离时所对应的流量,将基于此流量计算获得的临界剪切力作为实测值。比较临界剪切力计算值与实测值验证WEPP模型估算的可靠性。结果表明,在饱和/渗流条件下,土壤剥蚀率随着冲刷历时的增加逐渐减小;在排水条件下,放水流量为0.55 L/min的土壤剥蚀率随冲刷历时的增加快速减少并逐步稳定,而随着放水流量增大土壤剥蚀率波动的更为剧烈。5个水力梯度平均细沟可蚀性为2.51×10?2 s/m。饱和/渗流条件下细沟可蚀性为3.07×10?2 s/m,是排水条件的1.78倍。除水力梯度为?1.43 m/m时临界剪切力在WEPP模型中的计算值与实测值相符外,在?0.71~1.43 m/m范围内,临界剪切力的计算值均高估了实测值,平均高估了36.85%。临界剪切力实测值与计算值呈指数函数关系(R2=0.77,P0.01)。该研究可为黄壤的侵蚀防治及WEPP细沟侵蚀模型临界剪切力修正提供理论支持和科学指导。 相似文献
6.
不同土壤容重水平下喀斯特黄壤分离能力水动力学特性 总被引：2，自引：1，他引：1
通过开展不同流量(20,30,40,50,60 L/min)条件下的室内模拟细沟水流冲刷试验,研究不同容重(1.06,1.15,1.18,1.21 g/cm3)对喀斯特黄壤分离能力(D c)的影响,并建立土壤分离能力预测经验模型。结果表明:流量与容重均显著影响土壤分离能力,当容重为1.06 g/cm3时,D c随流量呈幂函数递增,而在其他更高的容重条件下,D c随流量呈线性增加;同一流量条件下,D c随容重增加呈线性减小,且减少趋势在高流量条件下更为明显;幂函数方程可分别描述D c与水流剪切力(τ)、水流功率(ω)、单位水流功率(P)、过水断面单位能量(E)间的关系,利用水流剪切力来预测土壤分离能力(R 2=0.96)更为理想;细沟可蚀性系数(Kτ、Kω、K P、K E)及临界水动力学值(τC、ωC、P C、E C)随容重增加均呈减小趋势,且容重与细沟可蚀性系数(Kτ、Kω、K P、K E)间存在线性关系。研究结果为阐明喀斯特地区土壤侵蚀机理、建立该地区土壤侵蚀过程模型提供理论依据。 相似文献
7.
为探究以干暖河谷为基带的西南山地土壤细沟可蚀性垂直地带性差异,选择该区不同垂直带典型土地利用类型(林草地和耕地)下不同土壤类型(红壤、黄壤、棕壤和暗棕壤)为研究对象,利用室内“V”形细沟模拟装置,分别进行6种流量(150,300,450,600,750,900mL/min)和3种水文状态(排水状态、饱和状态和渗流状态)的模拟冲刷试验。结果表明:(1)该区土壤颗粒组成无明显的垂直地带性,林草地的砂粒含量偏高,各土壤的颗粒含量差异在9%以内,所有土壤均为粉质壤土,但有机质差异较大,且随着海拔增加而增加;(2)土壤的细沟可蚀性具有明显的垂直地带性,随海拔升高,林草地土壤可蚀性Kr值逐渐减小,相比于红壤,暗棕壤的Kr值减小幅度平均为47.74%,耕地土壤中黄壤略大于红壤,可能与人为活动强度和土壤熟化程度有关;(3)不同土地利用方式下,林草地土壤Kr值显著大于耕地土壤Kr值,平均增幅为22.63%,这可能与有机质促进土壤抗侵蚀性能的提高有关;(4)不同近地表水文状态下,土壤的细沟可蚀性表现为渗流状态>饱和状态>排水状态,表明随着近地表水文状态变化,尤其是垂直水力梯度的增加会显著导致土壤的细沟可蚀性增大;试验还发现,土壤的临界剪切力仅在不同的水文状态下具有渗流状态>饱和状态>排水状态的规律性,而在不同海拔和土地利用类型之间没有明显的规律性。 相似文献
8.
黄土高原不同退耕年限刺槐林地土壤侵蚀阻力 总被引：7，自引：3，他引：4
为了明确黄土高原植被恢复后不断蓄积的枯落物对土壤分离过程的影响,论文选取10、15、20、30、40a退耕年限刺槐林样地及对照样地,采集180个土壤样品用于土壤分离试验,在6组侵蚀动力条件下进行变坡水槽冲刷试验,结果表明:随着退耕年限的增大,刺槐林土壤结构趋于稳定且疏松多孔,40年刺槐林地与对照样地相比:容重降低12.9%、总孔隙度增加10.1%、毛管孔隙度增加62.4%,土壤有机质含量增加97.9%、水稳性团聚体增加112.3%.土壤分离能力均值随着林龄呈指数函数递减(R2=0.82、P<0.05).在退耕0~40年范围内,在0~15 a内土壤分离能力下降迅速,对照、10 a刺槐林地、15年刺槐林地之间的土壤分离能力差异显著(P<0.05),退耕15 a以后土壤分离能力趋于稳定.40 a林龄刺槐林细沟可蚀性比对照的细沟可蚀性降低86.3%,临界剪切力提高10.1%.土壤临界剪切力变化范围在4.15~4.78 Pa之间.细沟可蚀性的变化趋势与土壤分离能力变化趋势相似,相比临界剪切力的变化,细沟可蚀性的变化更能反映土壤分离能力的变化情况. 相似文献
9.
东北黑土区土壤侵蚀强烈发育,导致黑土地严重退化,直接威胁区域生态安全和国家粮食安全。秸秆还田是黑土区广泛采用的保护性耕作措施,具有明显的阻控土壤侵蚀、抑制土壤退化、提升退化黑土地生态生产功能的作用。本文在系统分析秸秆还田阻控细沟间、细沟、浅沟与切沟侵蚀机理,综合评价秸秆还田水土保持效应的基础上,提出了未来研究亟待加强的重点内容。秸秆还田阻控侵蚀的机理与侵蚀类型直接相关。秸秆覆盖消减降雨动能、抑制土壤物理结皮发育、维持土壤入渗性能、增加地表随机糙率、降低坡面径流流速、减小径流挟沙力和剪切力,是秸秆还田阻控细沟间和细沟侵蚀的直接作用。秸秆分解改善土壤理化性质、促进团聚体发育并提升其稳定性,引起作物生长特性变化,导致细沟间土壤可蚀性和细沟土壤可蚀性降低,土壤临界剪切力增大,是秸秆还田阻控细沟间和细沟侵蚀的间接作用。尽管秸秆还田阻控浅沟和切沟侵蚀的作用不如细沟间和细沟侵蚀那样直接,但仍可通过减小集水区径流侵蚀动力来降低浅沟和切沟发育风险。秸秆还田具有显著的水土保持效应,减流和减沙效益分别为28.0%~95.1%和40.3%~99.7%。但受不同试验条件差异的影响,研究结果可比性较差。未来亟需加强秸秆还田增加地表糙率与径流阻力、降低径流挟沙力水力学机理,土壤抗蚀性能对秸秆还田驱动土壤理化性质变化的响应机制,秸秆还田水土保持效应受土壤类型与坡度的影响及主控因素,秸秆还田阻控侵蚀的长期效应与空间分异,以及秸秆还田技术影响土壤侵蚀过程与机理等研究,为遏制黑土地退化、维持黑土区生态安全、保障国家粮食安全提供理论和技术支撑。 相似文献
10.
饱和状态下黄绵土坡面细沟侵蚀可蚀性和临界剪切应力特征 总被引：1，自引：1，他引：0
土壤可蚀性参数和临界剪切应力是评价土壤易侵蚀程度和抗水流剪切变形能力的重要指标,目前在黄绵土坡面细沟侵蚀过程中,土壤饱和条件下可蚀性参数和临界剪切应力的变化尚不明确。该研究采用室内土槽模拟冲刷试验确定不同坡度（5°、10°、15°、20°）和流量（2、4、8 L/min）下饱和黄绵土坡面的最大细沟剥蚀率,基于数值法、修正数值法和解析法计算土壤可蚀性参数和临界剪切应力。结果表明,3种方法所得最大细沟剥蚀率均随坡度和流量增加而增大,其中修正数值法和解析法计算的最大细沟剥蚀率更接近。土壤可蚀性参数分别是0.485、0.283和0.268 s/m,土壤临界剪切应力分别为1.225、1.244和1.381 N/m2。修正数值法可提高数值法近似计算的精度,使近似计算结果更接近解析法计算获得的理论值。饱和较未饱和黄绵土的土壤可蚀性参数略有减小（16.83%）,而临界剪切应力减小了66.97%,表明土壤饱和对黄绵土土壤可蚀性参数影响很小,但大幅度削弱了土壤临界剪切应力,使得黄绵土坡面饱和后土壤侵蚀更为强烈。此外,饱和黄绵土边坡的临界剪切应力比饱和紫色土坡面大6.38%,而细沟可蚀性参数大2.35倍,表明土壤饱和对2种土壤临界剪切应力影响程度相似,但黄绵土较紫色土对土壤侵蚀的敏感性更高。研究结果可为饱和状态下不同土壤坡面细沟侵蚀模型参数的优化提供参考。 相似文献
11.
A rational method for estimating erodibility and critical shear stress of an eroding rill 总被引：2，自引：0，他引：2
Soil erodibility and critical shear stress are two of the most important parameters for physically-based soil erosion modeling. To aid in future soil erosion modeling, a rational method for determining the soil erodibility and critical shear stress of rill erosion under concentrated flow is advanced in this paper. The method suggests that a well-defined rill be used for shear stress estimation while infinite short rill lengths be used for determination of detachment capacity. The derivative of the functional relationship between sediment yield and rill length at the inlet of rill flow, as opposed to average detachment rate of a long rill, was used for the determination of detachment capacity. Soil erodibility and critical shear stress were then regressively estimated with detachment capacity data under different flow regimes. Laboratory data of rill erosion under well defined rill channels from a loess soil was used to estimate the soil erodibility and critical shear stress. The results showed that no significant change in soil erodibility (Kr) was observed for different slope gradients ranging from 5 to 25 while critical shear stress increased slightly with the slope gradient. Soil erodibility of the loess soil was 0.3211 ± 0.001 s m− 1. The soil erodibility and critical shear stress calculations were then compared with data from other resources to verify the feasibility of the method. Data comparison showed that the method advanced is a physically logical and feasible method to calculate the soil erodibility and critical shear stress for physically-based soil erosion models. 相似文献
12.
Determination of rill erodibility and critical shear stress of saturated purple soil slopes 总被引：1，自引：0，他引：1
《国际水土保持研究(英文)》2022,10(1):38-45
The hydrological conditions near the soil surface influence the soil erosion process, as determined by the soil erodibility and critical shear stress. The soil erodibility and critical shear stress of saturated purple soil slopes were computed and compared with those of unsaturated purple soil slopes. The detachment capacities computed through the numerical method (NM), modified numerical method (MNM) and analytical method (AM), from rill erosion experiments on saturated purple soil slopes at different flow rates (2, 4, and 8 L min?1) and slope gradients (5, 10, 15, and 20°), were used to comparatively compute the soil erodibility and critical shear stress. The computed soil erodibilities and critical shear stresses were also compared with those of unsaturated purple soil slopes. At the different slope gradients ranging from 5° to 20°, there were no significant differences in the soil erodibilities of the saturated purple soil and also in those of the unsaturated purple soil. The critical shear stresses slightly varied with the slope gradients. The saturated purple soil was relatively significantly more susceptible to erosion. The NM overestimated the soil erodibility of both saturated and unsaturated soils by 31% and underestimated the critical shear stress. The MNM yielded the same soil erodibility and critical shear stress values as the AM. The results of this study supply parameters for modeling rill erosion of saturated purple soil slope. 相似文献
13.
Samira Zamani 《Archives of Agronomy and Soil Science》2013,59(12):1743-1753
Wind erosion is a serious problem, especially in arid and semi-arid regions. This study was conducted to assess the effects of wind speed as well as soil particle-size distribution on erosion rate (ER) using a wind tunnel. For this purpose, two clay loam soil samples (C2 and C10) in addition to a sandy clay loam (S2) were exposed to different wind velocities of 2, 9 and 18 m s?1. The result showed that erosion rate increased significantly with increasing wind speeds. In addition, a critical diameter of 0.84 mm for soil particles was supported; for larger particles the changes in erosion rate were negligible. Furthermore, soil erodibility (K) was determined, which for S2, C2 and C10 was 57.73, 10.27 and 1.43, respectively. To predict soil erodibility, a power relationship as K = 3.382 MWD?1.732 (R 2 = 0.99) was established. The results indicated with increasing wind speed, the sensitivity of S2 remained constant, whereas C2 and C10 resisted wind speed. The finding of this research indicates the importance of particle-size distribution on wind erosion rate as well as soil erodibility. 相似文献
14.
饱和与非饱和黄绵土细沟径流水动力学特征及侵蚀阻力对比 总被引：7，自引：3，他引：4
近地表水文状况显著影响坡面土壤侵蚀过程。土壤饱和状态作为一种特殊的近地表水文状况,其细沟侵蚀特征较之非饱和状态存在明显的差异。以黄绵土为研究对象,采用限定性细沟模拟冲刷,对比研究了饱和与非饱和状态下黄绵土的水动力特征和侵蚀阻力。结果表明:饱和黄绵土径流流速与坡度、流量之间符合良好的幂函数关系,坡度对流速的影响更甚;饱和黄绵土径流流速约为非饱和黄绵土的1.17倍,其坡面摩擦阻力仅为非饱和黄绵土的70.3%;同种工况下,非饱和黄绵土的径流含沙量和细沟径流动能明显偏低,随着径流动能增大,2种土的径流含沙量均呈现对数型增长,径流含沙量峰值稳定在400,280kg/m~3内;饱和与非饱和黄绵土的细沟可蚀性参数分别为0.088,0.057kg/(m~2·s),相应的土壤临界剪切力分别为0.773,1.561Pa,表明饱和黄绵土更易剥蚀、流失。 相似文献
15.
《国际水土保持研究(英文)》2021,9(4):520-531
This research aims to improve erosion control practice in the Loess Plateau, by studying the surface erosion processes, including splash, sheet/interrill and rill erosion in four contrasting soils under high rainfall intensity (120 mm h−1) with three-scale indoor artificial experiments. Four contrasting soils as sandy loam, sandy clay loam, clay loam and loamy clay were collected from different parts of the Loess Plateau. The results showed that sediment load was significantly impacted by soil properties in all three sub-processes. Splash rate (4.0–21.6 g m−2∙min−1) was highest in sandy loam from the north part of the Loess Plateau and showed a negative power relation with the mean weight diameter of aggregates after 20 min of rainfall duration. The average sediment load by sheet/interrill erosion (6.94–42.86 g m−2∙min−1) was highest in clay loam from middle part of the Loess Plateau, and the stable sediment load after 20 min showed a positive power relation with the silt content in soil. The average sediment load increased dramatically by rill and interrill erosion (21.03–432.16 g m−2∙min−1), which was highest in loamy clay from south part of the Loess Plateau. The average sediment load after the occurrence of rill showed a positive power relation with clay content and a negative power relation with soil organic matter content. The impacts of slope gradient on the runoff rate and sediment load also changed with soil properties. The critical factors varied for different processes, which were the aggregate size for splash erosion, the content of silt particles and slope gradient for sheet/interrill erosion, and the content of clay particles, soil organic matter and slope gradient for rill erosion. Based on the results of the experiments, specific erosion control practices were proposed by targeting certain erosion processes in areas with different soil texture and different distribution of slope gradient. The findings from this study should support the improvement of erosion prediction and cropland management in different regions of the Loess Plateau. 相似文献
16.
《Land Degradation \u0026amp; Development》2017,28(5):1496-1505
Soil erosion from cropland is a primary cause of soil degradation in the hilly red soil region of China. Soil characteristics and the resistance of soil to erosion agents can be improved with appropriate management practices. In this study, hydraulic flume experiments were conducted to investigate the effects of five management practices [manure fertilizer (PM), straw mulch cover (PC), peanut–orange intercropping (PO), peanut–radish rotation (PR) and traditional farrow peanut (PF)] on soil detachment. Based on the results, three conservation management practices (PC, PM and PO) increased the resistance of soil to concentrated flow erosion. The rill erodibility of different treatments was ranked as follows: PC (0·001 s m−1) < PM (0·004 s m−1) < PO (0·007 s m−1) < PF (0·01 s m−1) < PR (0·027 s m−1). The rill erodibility was affected by soil organic content, aggregate stability and bulk density. The soil detachment rate was closely correlated with the flow discharge and slope gradient, and power functions for these two factors were developed to evaluate soil detachment rates. Additionally, the shear stress, stream power and unit stream power were compared when estimating the soil detachment rate. The power functions of stream power and shear stress were equivalent, and both are recommended to predict detachment rates. Local soil conservation can benefit from the results of this study with improved predictions of erosion on croplands in the red soil region of China. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献