不同水土保持措施对坡地养分的影响

对不同水土保持措施对坡地养分的影响进行了研究,结果表明:采取百喜草覆盖或敷盖措施的坡地土壤的养分均得到了提高,养分空间分布差异也明显小于裸露对照,养分空间分布规律为上坡大于中坡大于下坡,横坡方向上养分分布差异不明显,养分有明显的表聚性,速效氮的平面空间分布差异大于有机质和全氮,垂直空间上分布差异速效氮小于有机质和全氮;分析表明采取百喜草覆盖和敷盖措施可以有效提高土壤养分含量并且减小养分的空间分布差异,其中以百喜草覆盖措施效果最好。     

南方红壤丘陵区不同生态恢复措施对土壤质量的影响

对南方红壤丘陵区的荒坡地采取不同生态恢复措施后的土壤理化性质指标进行了测定,分析结果表明:前埂后沟梯壁植百喜草的梯田果园对减小土壤密度、提高土壤持水能力和改善土壤通气状况的效果最好,横坡间种农作物的坡地果园对改善土壤结构效果最好;采取不同生态恢复措施的土壤有机质、全氮、全磷、全钾、速效磷含量均高于裸露地,且以前埂后沟梯壁植百喜草的梯田果园各指标含量最高。采取不同生态恢复措施的土壤碱解氮含量和速效钾含量同样以前埂后沟梯壁植百喜草的梯田果园最高。试验结果表明,采用不同措施的生态果园对土壤的生态恢复效果较好,尤以前埂后沟梯壁植百喜草梯田果园效果最好。     

烟草种植区坡耕地水土流失特征及影响因素

控制烟草种植区坡耕地水土流失对提高农业种植水平、保护生态环境具有重要意义。通过重庆黄壤坡地野外监测试验,研究了不同农作处理下烤烟坡耕地产流—产沙特征。结果表明:①坡度与地表径流量、侵蚀泥沙量呈显著的正相关关系,23°坡地地表径流量和侵蚀泥沙量为10°坡地的1.3~3.0倍;②横坡垄作处理沿等高线起垄,能明显减小地表径流量和侵蚀泥沙量,横坡垄作处理侵蚀泥沙量占顺坡垄作处理的14%~45%;③垄间秸秆覆盖可以有效减小地表侵蚀泥沙量,其侵蚀泥沙量仅为未覆盖处理的47.25%;④在烤烟生长后期,地表覆盖率达到最大化,各处理方式下侵蚀泥沙量都趋于减小。     

倾斜摄影测量技术在水利工程测绘中的应用

为研究赣北柑橘园不同地表覆被措施对土壤抗蚀性及其减流减沙的影响,采用野外径流小区定位观测试验,分析了裸露对照、带状覆盖百喜草、顺坡耕作和横坡耕作等4种措施对土壤团聚体组成、抗蚀性及产流产沙特征的影响。结果表明横坡耕作措施土壤团聚体破坏率最低,其次是顺坡耕作措施。带状覆盖百喜草措施水稳定性团聚体（WSA）含量、干筛与湿筛团聚体平均重量直径（MWD）最高,土壤抗蚀能力最强,减流、减沙效果亦最佳。与裸露对照相比,横坡耕作和顺坡耕作措施在产生一定经济收益的同时,能有效提升土壤理化性质及抗蚀性,但在减流、减沙效益上弱于带状覆盖百喜草。因此,在实际应用中,可采用带状覆盖和耕作措施相结合模式来提升水土保持综合效益。     

水库消落带百喜草单混种植适应性研究

红壤区水库消落带植被恢复难度高,目前相关研究较少。文章通过研究在野外模拟红壤区水库消落带水位变化,表明百喜草对水淹环境有较好的适应能力,与岸坡种植无差异;混植香根草后其指标呈现更加稳定甚至叶宽、分蘖数有一定升高的趋势;能够改善土壤酸碱度、提高或稳定有机质、P、N、K含量,具有活化土壤速效养分的性能。单种和混植香根草均可推荐作为红壤区周调节水库消落带植被恢复的植物种,并提供了香根草作为百喜草共生草种的成功案例,针对性提出了减缓低温与水淹叠加效应、混植机理研究等后续研究方向。     

不同地表覆被对赣北柑橘园土壤抗蚀性及产流产沙的影响

为研究赣北柑橘园不同地表覆被措施对土壤抗蚀性及其减流减沙的影响,采用野外径流小区定位观测试验,分析了裸露对照、带状覆盖百喜草、顺坡耕作和横坡耕作等4种措施对土壤团聚体组成、抗蚀性及产流产沙特征的影响.结果表明横坡耕作措施土壤团聚体破坏率最低,其次是顺坡耕作措施.带状覆盖百喜草措施水稳定性团聚体(WSA)含量、干筛与湿筛...     

毛竹林地不同植被恢复模式的土壤物理性质评价

毛竹林地过度经营开发导致了林地生态系统的恶化,通过实施林下灌草植被恢复可以改善林地植被结构、增强水土保持功能和改善林地土壤性状。因此,开展毛竹林下不同植被恢复模式的土壤物理性质评价,有利于指导毛竹林的经营与管理。采用灰色关联分析法研究了毛竹纯林下种植灌木和种植灌草两种植被恢复模式对土壤持水能力和孔隙状况的影响。研究结果表明:对过度开发毛竹林地进行植被恢复可以增加土壤非毛管孔隙数量,提高土壤持水能力11%～26%,土壤持水能力与孔隙数量有密切的关系。毛竹纯林、毛竹林下种植灌木和种植灌草模式的灰色关联度平均值分别为0.5273,0.6441和0.7652,说明毛竹纯林下种植灌草植被模式的土壤物理性质最优,该模式可以显著改善毛竹纯林地的土壤物理性质。     

半干旱黄土丘陵沟壑区不同植被类型减蚀效应及其时间变化

在半干旱黄土丘陵沟壑区,植被恢复与重建是脆弱生态区生态修复的重要途径.但对植被恢复重建的类型选择及其水土保持功能仍然有很多争议.在自然降水条件下,基于4种植被类型与农作物的径流场对比试验的连续观测(14年),可以反映植被重建和恢复过程水土保持功能的时间基本变化特征.结果表明:植被恢复与重建显著地减少了土壤侵蚀量,但不同类型之间存在显著差异.土壤侵蚀量从高到低依次为:农耕坡地、苜蓿地、油松林地、针茅草地、沙棘林地.     

植被坡面产流特征及其侵蚀动力研究进展

植被覆盖变化状况直接影响流域水文过程,通过对黄土高原植被坡面产流特性已有研究成果进行总结,以期为评价植被对水沙调控的作用提供参考。从黄土高原生态建设和水土保持效益评价的需求出发,回顾了植被作用下坡面产流特征和侵蚀动力学特性研究的主要进展,包括植被增强土壤入渗能力和减缓径流的作用、植被对坡面产流的影响、植被作用下坡面流侵蚀动力学特性;明确了需进一步深化研究的主要方向,包括植被作用下坡面降雨-入渗非线性过程、坡面产流机制发生胁变的被覆临界、不同产流机制的侵蚀动力参数特性等。     

生草覆盖条件下不同降雨强度对紫色土坡面侵蚀产沙的影响

造林种草,增加植被覆盖度是防止土壤侵蚀的重要措施.通过人工模拟降雨试验,探讨生草覆盖下紫色土坡面侵蚀产沙的动态变化.结果表明,有生草覆盖的坡面径流含沙量较裸地的径流含沙量更快达到稳定状态;坡面侵蚀产沙率随覆盖度增加呈指数型递减,且坡下种草的减沙效果最好;覆盖度与降雨强度对坡面侵蚀产沙量的影响存在对比消长关系,但生草覆盖度对产沙量的影响小于降雨强度的变化对产沙量的影响.     

种植不同作物对土壤抗剪强度影响

为了确定不同作物种植对土壤抗剪强度的影响,以辽宁省摩云山小流域为研究对象,分别采集大豆地、玉米地、果树地和果树台田样本等土样。测定土壤含水量,利用直剪法测定土壤黏聚力和内摩擦角,分析同一种作物和不同作物的土壤剪切力与土壤含水量关系以及同一种作物和不同种作物的内摩擦角的关系。结果表明:土壤黏聚力玉米地(49.27kPa)豆地(38.36kPa)果树台田(30.00kPa)果树地(28.36kPa);内摩擦角果树地(25.45°)豆地(23.26°)玉米地(20.24°)果树台田(19.51°);玉米地的剪切力与豆地的剪切力、果树地的剪切力和果树台田的剪切力均有显著性差异;不同作物的土壤黏聚力和土壤含水量进行二次线性分析,拟合度较好。     

作物覆盖与径流能量的关系

黄土高原的土壤侵蚀往往是由几场大的暴雨形成的，因此研究植被覆盖与径流的能量关系具有积极的现实意义。在整理分析了黄土高原西峰、绥德、天水、淳化4个水土保持试验站降雨、径流及泥沙资料的基础上，探讨了作物覆盖与径流能量的关系。结果表明：①作物覆盖对径流能量具有消减作用，其削减率平均值为72．4％；②作物覆盖与平均径流能量削减率之间呈直线关系；③作物覆盖的削减能量作用受降雨动能的影响，随降雨动能的增大，植被对径流能量的削减作用减小。     

我国植被恢复对土壤性状影响研究综述

 生态修复是改善生态环境的重要手段,对于土壤、水文、植被等多方面具有影响。介绍了植被恢复对土壤水分、土壤密度、土壤有机质、土壤氮等4个方面的影响。结果表明：①植被恢复对土壤的影响有利有弊,大多数情况下植被恢复降低土壤水分,提高养分含量,降低土壤密度;②从不同的指标来看,植被恢复改善土壤性状所需时间不同,从3年至20年以上;有些立地条件下,人工造林土壤性状长期低于天然林;③对于改善土壤性状没有明显作用的植物种,在进行合理配置后,有可能产生很好的改良土壤作用。在此基础上提出植被恢复需进一步明确的各类指标目标阈值及措施。     

Modeling Effects of Land use and Vegetation Density on Soil Water Dynamics: Implications on Water Resource Management

Vegetation restoration is helpful in preventing soil erosion but aggravates water scarcity, thus resulting in soil desiccation on the wind–water erosion crisscross region (WWECR) of the Loess Plateau in Northwestern China. However, no guideline currently exists on the selection of plant species and density for restoration purposes. Based on the process model of soil water-carrying capacity for vegetation (SWCCV) originally developed in this region, this study validated the model under a broad range of weather regimes, soil types, and land uses. The SWCCV model was applied as a diagnostic tool to obtain insights into the separate effects of vegetation density and land use on soil water dynamics on the WWECR of the Loess Plateau. Results showed that the total water loss at semi-natural grasslands was close to rainfall while significantly decreasing runoffs, thus indicating that semi-natural grass was suitable for vegetation restoration on the WWECR. If Caragana korshinskii is planted for agronomic and economic benefits, a density of 3,400 trees ha^?1 will yield the most optimal soil water conservation benefits at study site. Our recommended land use and vegetation density were directive and instructional for vegetation restoration on the WWECR and that our modeling approach could be extended to applications in other arid and semi-arid regions.     

Soil seed banks of degraded riparian zones in southeastern Australia and their potential contribution to the restoration of understorey vegetation

Although soil seed banks are understood to be integral to the vegetation dynamics and restoration of many ecosystems, little is known of their role in riparian zones. In this study, we investigated soil seed banks of riparian zones of contrasting condition in an agricultural landscape and evaluated their potential to influence riparian restoration. We examined the composition and structure of germinable soil seed banks along lateral gradients from stream channels in both cleared and wooded riparian zones of three lowland creeks within the Goulburn Broken catchment in temperate southeastern Australia. Environmental correlates of soil seed bank characteristics and similarity to extant vegetation were also examined. We found an abundant and species‐rich soil seed bank mostly comprising propagules of perennial rushes and sedges and annual and perennial grasses with many species of annual forbs. While the majority of identifiable germinants and species were native, exotic species were common at all locations. Soil seed bank composition was relatively homogeneous among streams and along lateral gradients from the channel. Riparian condition (i.e. cleared or wooded), however, had a strong influence on soil seed bank composition and structure with cleared reaches containing more species, more germinable annual grasses and higher total numbers of germinable seeds. Soil seed bank composition was correlated with site openness suggesting that extant vegetation structure plays an important role in soil seed bank dynamics. Recruitment from the in situ soil seed bank will help restore only some components of the riparian plant community and may hinder restoration by introducing undesirable species. Copyright © 2008 John Wiley & Sons, Ltd.     

太行山山地丘陵区雨季土壤水分动态规律研究——以崇陵流域为研究区

以河北易县崇陵丘陵山区为研究对象，在实验的基础上，针对主要土壤质地、坡度和植被，研究不同下垫面条件下土壤水分变化规律，得到典型土壤质地的物理参数，并对土壤水分的动态变化规律进行了研究。实验结果表明，土壤质地对土壤物理参数和土壤水分变化影响非常大，明显强于植被和坡度。土壤质地对表层和深层水分的变化影响很大，活跃层受质地影响相对较小。     

土壤水分植被承载力数学模型的初步研究

本文通过对不同密度林地根层土壤水分补给和消耗量的分析，提出确定土壤水分植被承载力的概念模型。通过对不同密度人工林地根层土壤水分补给和消耗的定位监测资料分析，建立了土壤水分植被承载力的数学模型。通过实例分析可以看出，该方法是简便易行。     

Regional differences in nutrient limitation in floodplains of selected European rivers: implications for rehabilitation of characteristic floodplain vegetation

Extremely high river discharges in 1993 and 1995 along the Dutch rivers Rhine and Meuse have increased the public awareness of possible safety threats. As a result the ‘Space for Rivers’ program was implemented, aiming at restoring physical space for the rivers in combination with ecological rehabilitation. However, the development of species‐rich vegetation types in these floodplain areas is lagging behind restoration targets and biogeochemical constraints may play a vital role in this. Biogeochemical, hydrological and vegetation data were collected in 111 plots in both rehabilitated and original floodplains in regulated and more pristine river systems in The Netherlands and Poland. Soil nutrient and soil pore water data were summarized by factor analysis and the subsequent principal components were compared to vegetation and hydrological data by correlation analysis. The correlation analyses between vegetation parameters including nutrient stoichiometry and the biogeochemical soil variables resulted in a remarkable difference between pristine and impacted river systems. The results suggest a clear N‐limitation of plant growth in pristine floodplains, and apparent absence of limitation in regulated, impacted floodplains. In addition, results indicate that flooding events do not lead to one‐way transport of sediment and nutrients from the river into the floodplains; rather they indicate that highly dynamic hydrological conditions prevent soils from accumulating organic matter and nutrients. This study shows that nutrient limitation in regulated floodplains shifted from distinctly N‐limited plant growth to no nutrient limitation at all, probably due to decades of high fertilizer and manure application and nutrient input by the rivers during flooding. The consequence of our findings for rehabilitation activities is that it might be necessary to restore nitrogen limitation in floodplain systems in order to create opportunities for a species‐rich floodplain vegetation, through nutrient removal by hay‐making. Copyright © 2006 John Wiley & Sons, Ltd.     

基于透水混凝土渗灌不同灌水量对低丘红壤区蜜桔生长的影响

为研究不同灌水量对丘陵红壤区蜜桔生长的影响,对南丰县大田蜜桔进行透水混凝土渗灌试验。在实验地设置3 个不同灌水量水平（H1 低水,H2 中水,H3 高水）的灌溉处理,结果表明：土壤水分垂向分布大致呈先增大后减小的趋势,当透水混凝土灌水器埋深在30cm 时土壤含水量到达峰值;在整个生育期内H2 灌水处理枝长增长率最大;同时灌水量越大,果型指数基本呈现减小的趋势;各灌水处理蜜桔糖分随时间的增长而升高,H3 处理组果实糖分最高。综合蜜桔生长规律及枝长增长率、果实横纵径、果型指数、蜜桔糖分等4 个指标对水分调控的响应,得出对低丘红壤透水混凝土渗灌条件下H3为最佳灌水处理。