黄土丘陵林地土壤侵蚀与土壤性质变化

以黄土丘陵子午岭土壤侵蚀和生态环境观测站1989~1998年的观测资料为基础,研究分析了林地开垦10年内土壤侵蚀与生态环境变化的相互效应关系。分析指出:林地开垦人为改变侵蚀环境,引起的人为加速侵蚀速率为自然侵蚀速率的1000倍以上;以单位降雨侵蚀力引起的侵蚀量作为衡量指标,指出林地开垦地土壤侵蚀强度随侵蚀年限增长呈递增加剧趋势;通过分析土壤物理力学性质表明,林地开垦侵蚀10年土壤粘粒和物理性粘粒比林地分别减少2.74%和3.01%,土壤向粗骨化趋势发展,>0.25 mm水稳性团粒含量减少58.7%,土壤容重增大,抗剪强度下降,抵抗径流冲刷能力减弱,造成土壤侵蚀更易发生;应用相关分析表明,>0.25 mm水稳性团粒含量的改变对土壤侵蚀强度影响最大,其偏相关系数为0.9728,其次是土壤的粗粉粒和抗剪强度,偏相关系数分别为0.8879和0.6020;分析>0.25 mm水稳性团粒含量和抗剪强度与土壤侵蚀强度关系表明,林地开垦后侵蚀1年和侵蚀7年为土壤侵蚀加剧的转折年限,说明退化的侵蚀土壤和退化的生态环境加剧了土壤侵蚀的发生和发展。     

黄土丘陵小流域土地利用变化对水土流失的影响

在土壤侵蚀模型LISEM (Limburg Soil Erosion Model) 校正的基础上,模拟了陕北黄土丘陵沟壑区大南沟小流域5种土地利用方案的水土流失效应,旨在探讨土地利用变化对流域出口水土流失的影响。研究结果表明:流域出口的洪峰流速、径流总量和侵蚀总量的大小顺序为:1975年>1998年>25度退耕>20度退耕>15度退耕。1975年和1998年25度以上的陡坡耕地和休闲地均退耕还林还草,这2种土地利用格局的径流和侵蚀模拟值都显著大于3种退耕方案。在3种退耕方案中,20度和15度以上的陡坡耕地和休闲地逐步转变为果园/经济林地,3种退耕方案之间的水土流失差异不显著。相对于1975年土地利用来说,1998年土地利用能降低洪峰流速、径流量和侵蚀量约5%~10%;3种退耕方案的减流减沙效益更加显著,可以降低洪峰流速、径流量和侵蚀量约40%~50%。     

天然林择伐10 a后林地土壤理化性质研究

对天然针阔混交林弱度和中度择伐10 a后林地土壤的理化性质进行分析,结果表明:土壤密度和结构体破坏率均下降,而最大持水量和总孔隙度均上升;土壤有机质、全氮、水解氮和全磷的含量均上升,而全钾、速效钾和速效磷的含量均略有下降.说明弱度和中度择伐10 a后林地土壤结构稳定性、水分、孔隙状况和养分含量基本得到恢复,并有所改善.     

卧龙自然保护区土地利用变化对土壤性质的影响

森林景观受干扰后的次生演替、人工林种植与农业耕作等在许多方面影响着土壤性质的变化。研究选取了四川卧龙自然保护区作为研究地点 ,阐述湿润高山区的土地利用方式与土壤性质之间的关系。选择了六种典型的土地利用方式加以比较 ,方差分析结果表明 ,不同土地利用之间土壤容重、全氮、有机碳、速效磷、速效钾的含量差异显著。相比之下 ,农田土壤养分含量偏低 ,而灌丛有着较高的有机碳、总氮与有效氮含量。 0～ 4 0cm土壤碳的储量变化幅度不大。综合土壤退化指数表明 ,坡耕地 ,撂荒地与人工林有土壤退化的趋势 ,而灌丛与次生林对土壤的性质有着改善的作用。人工林年龄与土壤有机碳、有机氮的含量正相关。     

沙盖黄土丘陵坡地土壤理化特性随地形变化规律研究

在陕西神木县与内蒙古东胜市交界的饮马泉小流域,选择有代表性的坡面进行地形剖面和土壤层垂直方向的系统采样。每个样品进行了粒级、土壤质量含水量、土壤有机质测试。经数据的分析模拟,得以下结论:①土壤粒级构成和物理性粘粒含量特征,可以指示研究区土壤的沙化程度和演化趋向,其具有向西北更干旱粗化方向过渡的倾向。②土壤水分随地貌部位的变化规律比较明显,在峁坡顶部和上部,垂向上具有自上而下增加的趋势,而在峁坡下部和坡脚却正好相反。不论何种地貌部位都存在一个相近的土壤蒸发、渗漏、持水能力相对的平衡深度。③土壤的物理性粘粒含量与土壤的水肥关系密切,物理性粘粒含量相对高的土壤剖面,土壤的水肥组合效果较好。④土壤水肥质地的组合效果,丘陵顶部的最差,依次过渡到坡脚的组合效果最好。其进一步表明,地貌因素在土壤形成后的一系列熟化、退化、被侵蚀和沙化的演化过程中,地貌仍起着至关重要的作用。     

大姚县生态修复区土地利用变化对土壤侵蚀的影响

利用USLE方程和径流场对大姚县水土保持生态修复区土壤侵蚀进行监测,旨在探讨采取退耕还林、封禁、坡改梯等修复措施后,土地利用变化对修复区土壤侵蚀的影响.研究结果表明：高强度土壤侵蚀主要发生在坡耕地特别是陡坡耕地,而林地和梯地少有发生;经过退耕还林增加林地面积和坡改梯后,土壤侵蚀现象得到缓解,流失面积减少2 867.35 hm^2.     

东北黑土漫岗区长坡面坡耕地侵蚀产沙沿程变化

Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on seg-ments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm,Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation,rill cannot happen within the top 50 m,while in a year with large and inten-sive precipitation,rill can be formed starting even at 15 m from the top of the slope.     

Soil erosion along a long slope in the gentle hilly areas of black soil region in Northeast China

Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on seg-ments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm, Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation, rill cannot happen within the top 50 m, while in a year with large and inten-sive precipitation, rill can be formed starting even at 15 m from the top of the slope.     

基于地形指数的砒砂岩黄土区土壤侵蚀分析

地形是土壤侵蚀进程的重要控制因子,在土壤侵蚀评价中发挥着重要作用.基于地形起伏表达构建了地形指数,结合降雨侵蚀力和植被盖度等建立了基于地形指数的土壤侵蚀方程,并分析了内蒙古自治区鄂尔多斯市北部十大孔兑砒砂岩黄土区1985-2018年土壤侵蚀时空变化特征.结果 表明:(1)研究区多年土壤侵蚀模数整体有下降趋势但变化差异不...     

黄土丘陵区典型退耕恢复植被土壤生态化学计量特征

为探究不同植被土壤碳(C)、氮(N)、磷(P)化学计量特征及其影响因素,以黄土丘陵区油松、刺槐、沙棘和草地4种典型退耕恢复植被0～100 cm土壤为研究对象,分析不同植被土壤有机碳(SOC)、全氮(STN)、全磷(STP)含量及其化学计量特征。结果表明:(1)不同恢复植被对土壤养分含量有显著影响,刺槐的SOC、STN最高,油松的SOC、STN最低,STP表现为草地>刺槐>油松>沙棘。(2)不同恢复植被土壤养分具有“表聚性”,随土层深度增加,SOC和STN含量呈下降趋势,而STP的变异性较弱。特别是刺槐的SOC和STN在60～100 cm呈增加趋势。(3)不同恢复植被土壤SOC:STN(C:N)、SOC:STP(C:P)差异不显著(P>0.05),刺槐的土壤STN:STP(N:P)显著高于其他植被类型(P<0.05),土壤C:N、C:P、N:P均低于全球及全国平均水平,研究区有机质的分解速率较快,P的有效性高,植被生长主要受N元素限制。(4)研究区土壤C:N、C:P和N:P主要受SOC和STN影响;土壤养分与土壤含水量(SWC)和土壤容重(BD)呈负相关,与...     

Geodetection analysis of the driving forces and mechanisms of erosion in the hilly-gully region of northern Shaanxi Province

Journal of Geographical Sciences - This paper analyzes the spatial variation in soil erosion in the loess hilly-gully region of northern Shaanxi Province, China. It sums up existing research,...     

半干旱黄土丘陵区人工植被深层土壤干化效应

科学评估不同植被恢复模式的土壤干化效应是目前黄土高原生态恢复一个亟需解决的关键问题。本文以半干旱黄土丘陵区14种典型人工植被为例,通过构建土壤水分相对亏缺指数CSWDI和样地土壤水分相对亏缺指数PCSWDI,定量评估了不同植被深层土壤干化效应。研究发现:除农地和撂荒草地外,各植被深层土壤水分均随土层深度的增加而升高,深层土壤水分含量同土层深度之间呈一元线性关系。不同人工植被深层土壤相对干化程度存在差异,以油松林地最高,杨树侧柏混交林地最低。不同植被类型受其自身蒸腾耗水、根系特征和耕作等影响,土壤干化的程度在剖面上存在差异,但总体趋势为随深度增加而降低。针阔叶植被配置模式土壤水分状况要稍好于阔叶纯林的配置模式。     

The characteristics of gully erosion over rolling hilly black soil areas of Northeast China

In this study, short-term gully retreat was monitored from the active gullies selected in representative black soil area, using differential global positioning system (GPS). With the support of geographic information system (GIS), multi-temporal digital elevation models (DEM) were constructed from the data collected by GPS and used for further analysis. Based on the analysis of multi-temporal DEM, we discussed the erosion–deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed. The results are: (1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m, gully area extended 170–400 m2, net gully eroded volume 220–320 m3,and gully erosion modulus 2200–4800 t?km?2?a?1. (2) Compared with the mature gully the initial gully grows rapidly, and its erosion parameters are relatively large. The erosion parameters have not only to do with flow energy, but also with the growth phase. (3) There are significant seasonal differences in gully erosion parameters. The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season. (4) It is remarkable for freeze-thaw erosion in the black soil area of NE China. The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004, and the distance of gully head retreated maximally 6.4 m. (5) Due to freeze-thaw action and snowmelt, gully is primarily in the interior adjustment process in winter and early spring. There are much more depositions compared with that during rainy season, which can almost happen throughout the gully, while erosion mostly occurs near head, esp. for gullies having a relatively long history of development. On the other hand, the process of energy exchange with exterior dominates in rainy season. It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.     

中国东北漫岗黑土区切沟侵蚀发育特征

In this study, short-term gully retreat was monitored from the active gullies selected in representative black soil area, using differential global positioning system (GPS). With the support of geographic information system (GIS), multi-temporal digital elevation models (DEM) were constructed from the data collected by GPS and used for further analysis. Based on the analysis of multi-temporal DEM, we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed. The results are: (1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m, gully area extended 170–400 m², net gully eroded volume 220–320 m³, and gully erosion modulus 2200–4800 t·km⁻²·a⁻¹. (2) Compared with the mature gully the initial gully grows rapidly, and its erosion parameters are relatively large. The erosion parameters have not only to do with flow energy, but also with the growth phase. (3) There are significant seasonal differences in gully erosion parameters. The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season. (4) It is remarkable for freeze-thaw erosion in the black soil area of NE China. The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004, and the distance of gully head retreated maximally 6.4 m. (5) Due to freeze-thaw action and snowmelt, gully is primarily in the interior adjustment process in winter and early spring. There are much more depositions compared with that during rainy season, which can almost happen throughout the gully, while erosion mostly occurs near head, esp. for gullies having a relatively long history of development. On the other hand, the process of energy exchange with exterior dominates in rainy season. It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions. Foundation: Key Project for National Natural Science Foundation of China, No.40235056; The Ph.D. Programs Foundation of Ministry of Education of China, No.20030027015; China Postdoctoral Science Foundation, No.20070410482; Doctoral Foundation of University of Jinan, No.B0620; National Natural Science Foundation of China, No.40672158; Key Subject Foundation Supported by Shandong Province Author: Hu Gang (1976–), Ph.D and Associate Professor, specialized in soil erosion, environmental evolution and regional planning.     

秋免耕对坝上地区农田风蚀及土壤理化性质的影响

秋免耕是中国北方风蚀区农田保护性耕作的主要措施,对土壤风蚀的抑制作用已得到普遍验证,但对土壤性质的影响还缺乏足够认识,是否具有保墒作用还存在争议.以地处北方农牧交错带的河北坝上地区康保县作为典型研究区,采用野外调查取样和室内实验分析手段,通过比较秋免耕地与邻近秋翻耕地风蚀前后表层土壤理化性质变化的差异,研究秋免耕对土壤...