共查询到20条相似文献，搜索用时 203 毫秒
1.
人工生物土壤结皮特性及其集雨潜力的研究 总被引：2，自引：0，他引：2
为探讨在太行山半干旱区利用人工土壤生物结皮进行集雨的潜力和可行性,以自然生长的生物土壤结皮为种子,通过培育建立人工土壤生物结皮和生物结皮集雨,对人工土壤生物结皮建成后土壤物理性状、渗透率的变化及人工生物结皮集雨面的集流效率进行了研究。结果表明,人工土壤生物结皮与自然生长的生物结皮一样,可显著改变土壤的颗粒组成,使0~1 cm表层土壤的小颗粒物质含量增加、大颗粒物质减少,但对0~5 cm的土壤容重影响不显著。对土壤入渗速率的测定结果表明,人工培育的土壤生物结皮具有降低入渗速率的作用,与自然土壤相比,生物结皮的土壤初始入渗速率和稳定入渗速率分别下降59.1%和44.4%,达到稳定入渗的加水量也减少50.0%。人工营建的生物结皮集雨面的平均集雨效率达60.86%,与自然土面相比,提高23.0%。对集雨面效益分析表明,生物结皮集雨面不仅具有较高的集雨效果,且使用年限较长,并具有明显的减少地表径流沉积物含量,提高土壤抗蚀性的作用。综上结果可以看出,人工土壤生物结皮是一种极具潜力的绿色环保型集雨材料。 相似文献
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土壤水分入渗的观测方法很多,但在测定坡地生物结皮土壤水分入渗时均存在一定的缺陷。线源入流入渗法是可用于无结皮的坡地土壤水分入渗较为简便快捷的观测方法。以裸土为对照,采用线源入流入渗法和模拟降雨法测定了黄土丘陵区多藻少藓、半藻半藓、多藓少藻等不同类型生物结皮土壤水分入渗过程。结果表明:(1)线源入流入渗法可在不干扰生物结皮的情况下,快速、完整地反映土壤水分入渗过程,获取初始入渗速率、平均入渗速率及稳定入渗速率等重要参数;(2)线源入流入渗法所得研究区不同类型生物结皮的初始入渗速率范围为3~12 mm/min,平均入渗速率范围为0.5~4.5 mm/min,稳定入渗速率范围为0.3~1.8 mm/min,随着藓盖度的增加,其初始、平均、稳定入渗速率均呈现出显著差异;(3)线源入流入渗法测定的生物结皮土壤稳定入渗速率(y,mm/min)与人工模拟降雨试验所得入渗速率(x,mm/min)呈显著的线性相关关系(y=1.73x-1.24,R^2=0.376 8,ρ=0.539~*)。研究结果为坡地生物结皮土壤水分入渗速率的测定提供一种简单易操作的测定方法。 相似文献
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陕北水蚀风蚀交错区两种生物结皮对土壤饱和导水率的影响 总被引：8，自引：6，他引：8
该文以陕北水蚀风蚀交错区普遍发育的地表和地上两种生物结皮为研究对象，分别以3种非生物结皮（无结皮、物理结皮、去除生物结皮）为对照，使用盘式入渗仪测定其饱和导水率。结果表明：与无结皮土壤相比，两种类型生物结皮均可极显著降低土壤饱和导水率；与去除生物结皮土壤相比，两种类型生物结皮对土壤饱和导水率的降低均不显著；与有物理结皮发育的土壤相比，地表生物结皮对土壤饱和导水率的降低不显著，而地上生物结皮对土壤饱和导水率的降低显著。一方面，两种生物结皮对土壤饱和导水率均有明显降低作用，预示生物结皮在降雨活动中可能会增加径流、降低入渗，阻碍研究区水分亏缺条件下的植被恢复和生态与环境建设。另一方面，与不同的对照相比，生物结皮对土壤饱和导水率的影响截然不同，该结论可在一定程度上解释当前有关生物结皮影响土壤水分入渗方面所存在的分歧。 相似文献
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黄土丘陵区生物结皮对土壤入渗的影响 总被引：4，自引：4，他引：0
《水土保持学报》2015,(5)
为了明确生物结皮对土壤入渗的影响,在黄土丘陵区沿降雨梯度从南到北大致按等间距分别在宜君、富县、延安、子长、子洲、榆林、东胜选取7个生物结皮发育较好的试验样地,并分别以无结皮样地作为对照,使用盘式入渗仪记录入渗过程并计算各入渗参数。结果表明,生物结皮可显著增大土壤表层有机质含量,但对土壤容重和土壤质地的影响不显著。生物结皮具有显著抑制土壤入渗的作用,从南到北土壤入渗性能呈现逐渐增加的趋势,但存在局部波动;从南到北7个生物结皮样地的饱和导水率、土壤初渗率及30min累积入渗量分别为0.18~0.39mm/min,1.31~2.72mm/min及15.18~43mm,从南到北7个对照样地的饱和导水率、土壤初渗率及30min累积入渗量分别为0.13~0.60mm/min,1.19~2.45mm/min及11.90~52.34mm。土壤初渗率和累积入渗量主要受土壤质地和初始含水量影响,土壤初始含水量对有无生物结皮生长土壤入渗过程的影响比较类似,而土壤质地对有生物结皮生长的样地入渗过程影响更显著;有无生物结皮条件下土壤饱和导水率均受土壤质地的影响,且土壤质地对无结皮样点的影响更显著。 相似文献
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生物结皮坡面不同降雨历时的产流特征 总被引：4，自引：2，他引：4
黄土高原退耕还林(草)工程实施后,生物结皮广泛发育,显著影响坡面产流。已有大量研究探索了生物结皮对径流的影响,但相关结论存在较大分歧。该研究以黄土高原典型生物结皮坡面为研究对象,通过人工模拟降雨试验,研究了生物结皮坡面产流过程。结果表明:生物结皮坡面较翻耕后的裸土坡面显著降低了初始产流时间,裸土坡面初始产流时间是生物结皮坡面的1.59～3.04倍。生物结皮盖度与初始产流时间之间呈显著的负相关关系;降雨15min时与60 min时生物结皮对坡面径流的影响发生逆转,90 mm/h的雨强下,当降雨历时为15 min时,生物结皮坡面较裸土坡面增加75.42%的径流;当降雨历时为60min时,生物结皮坡面径流量较裸土坡面降低52.42%;生物结皮影响了土壤水分入渗速率,导致生物结皮坡面与裸土坡面随降雨历时变化的产流特征出现差异,裸土坡面降雨60 min时的入渗率较15 min时降低了34.30%,高盖度生物结皮坡面降低了6.38%;生物结皮对坡面入渗产流的影响与降雨历时有极大的关系,降雨历时不同,很可能得到截然相反的结论,考虑生物结皮因素的野外降雨试验,降雨历时应不少于45min。研究结果为解释生物结皮影响坡面入渗产流方面存在的分歧提供了科学依据,进一步明确了干旱半干旱地区生物结皮的水文效应。 相似文献
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黄土高原水蚀风蚀交错区藓结皮覆盖土壤的蒸发特征 总被引：1，自引：1，他引：0
土壤蒸发是地表水分平衡及能量交换的组成部分,是干旱和半干旱区水文循环的关键环节。为探究黄土高原水蚀风蚀交错区生物结皮对土壤蒸发的影响,以风沙土和黄绵土上发育的藓结皮为研究对象,通过模拟蒸发试验和自然蒸发试验,测定了不同蒸发条件下藓结皮覆盖土壤和无结皮土壤的蒸发强度,分析了藓结皮覆盖土壤的蒸发特征及其与无结皮土壤的差异。结果表明:(1)模拟蒸发试验中,藓结皮对土壤蒸发过程的影响表现出明显的阶段性,与无结皮土壤相比,藓结皮使土壤蒸发强度在大气蒸发力控制阶段降低了3.04%～15.46%(0.21～1.05 mm/d),在土壤导水率控制阶段增加了32.26%～187.07%(0.58～2.54 mm/d),在水汽扩散控制阶段增加了12.91%～87.73%(0.05～0.34 mm/d);土壤累积蒸发量大小表现为藓结皮覆盖土壤无结皮土壤。(2)自然蒸发试验中,6月16日至9月3日,无降雨时藓结皮覆盖土壤和无结皮土壤的蒸发速率均较低,藓结皮覆盖土壤的日平均蒸发量是无结皮土壤的1.12～1.42倍,自然降雨后二者的蒸发速率快速增加,降雨后土壤蒸发量是降雨前的2.20～8.55倍;在8月10—22日观测期内,藓结皮在雨后增加了土壤含水量,并对土壤蒸发起到促进作用,藓结皮覆盖土壤的累积蒸发量显著提高了19.22%～64.09%(F=21.85,P0.01)。研究表明,藓结皮覆盖增加了风沙土和黄绵土的水分蒸发强度,可能会对黄土高原水蚀风蚀交错区土壤水分保持产生不利影响。 相似文献
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为探究围封对灌丛草地土壤优先流的影响,以宁夏吴忠市盐池县典型荒漠草原区为研究区,通过野外入渗染色试验、图像处理分析等方法,对围封荒漠草原灌丛草地土壤优先流的影响进行评价。结果表明:(1)围栏封育与放牧管理样地土壤水分入渗特征存在差异,在围栏封育样地,草地、天然柠条林地、人工柠条林地的入渗染色图像分别在0—125,0—115,0—105 cm呈现均匀分布,而在125—240,115—150,105—140 cm呈现染色分支,在放牧管理样地,草地、天然柠条林地、人工柠条林地入渗染色图像分别在0—80,0—70,0—80 cm呈现均匀分布,围栏封育导致土壤优先流发生深度更大;(2)土壤剖面染色面积比表现为围栏封育草地＞围栏封育天然柠条林地＞围栏封育人工柠条林地＞放牧管理人工柠条林地＞放牧管理天然柠条林地＞放牧管理草地,土壤染色深度表现为围栏封育草地＞围栏封育天然柠条林地＞放牧管理草地＞放牧管理天然柠条林地＞围栏封育人工柠条林地＞放牧管理人工柠条林地,围栏封育管理会导致土壤剖面染色面积比及染色深度增大;(3)土壤优先流变异系数表现为放牧管理天然柠条林地＞放牧管理人工柠条林地＞围栏封育天然柠条林地＞放牧管理草地＞围栏封育人工柠条林地＞围栏封育草地,放牧管理导致土壤优先流程度增加,而围栏封育降低灌木林地及草地的优先流程度。因此,在荒漠草原等干旱半干旱地区,围栏封育可作为提升土壤水分均匀入渗深度、降低优先流发生程度、提高土壤水分利用效率的重要管理方式。 相似文献
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[目的] 研究城市化背景下草地土壤水分运动规律,为提升海绵城市建设水平提供科学依据和技术支撑。[方法] 以江苏省扬州大学扬子津校区农水与水文生态试验场的人工草地为研究区,利用实测降雨和同期土壤含水量数据对不同降雨事件下的雨水入渗深度进行分析。通过HYDRUS-1D模型对研究区土壤含水量变化过程进行模拟。[结果] 在小雨（<10 mm）和中雨（10~25 mm）事件中,研究区草地的雨水入渗深度分别小于15 cm和30 cm;在大雨（25~50 mm）到暴雨（>50 mm）事件中,雨水入渗深度通常超过30 cm,或可达60 cm以上;土壤含水量模拟值与实测值的均方根误差范围为0.012～0.034 cm3/cm3。[结论] 不同等级降雨事件下的草地雨水入渗深度存在明显差异,入渗深度总体上随着降雨量的增加而增加;HYDRUS-1D模型能够准确模拟不同等级降雨事件下的城市人工草地区雨水入渗深度。 相似文献
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为探究不同盖度生物结皮对入渗特征的影响,在红壤丘陵区咸宁选取第四纪黏土发育土壤(S型)和泥质页岩发育土壤(N型)上的生物结皮,设计6个盖度水平(裸地,1%~20%,20%~40%,40%~60%,60%~80%,80%~100%),使用微型圆盘入渗仪(mini disk)测定土壤入渗过程,探究入渗过程的影响因素,同时采用3种常见的入渗模型对入渗过程进行拟合,并评价模型适用性。结果表明:(1)相对于裸地,生物结皮发育提高土壤有机质和黏粒含量,增加结皮厚度和生物量,降低砂粒含量。(2)第四纪黏土发育土壤水分入渗特征随生物结皮盖度的增加而逐渐降低,初始入渗速率、稳定入渗速率、平均入渗速率、非饱和导水率的变化范围分别为0.25~1.55,0.13~0.91,0.17~1.11,2.04~8.48 mm/min。泥质页岩发育土壤除40%~60%盖度砾石含量较高,土壤水分入渗也随盖度的增加而逐渐减小,80%~100%盖度的初始、平均和稳定入渗率较裸地分别降低91.14%,87.64%和91.30%,生物结皮的存在阻碍土壤水分入渗。冗余分析表明,对于第四纪黏土发育土壤,生物量(54.30%)对其入渗特征的解释度最高,泥质页岩发育土壤则为盖度(39.30%)和砾石含量(34.00%)。(3)Horton模型、Kostiakov模型、Philip模型3种主流入渗模型中Horton模型拟合效果最优。研究结果可为揭示湿润区生物结皮水分运移规律提供科学参考。 相似文献
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Changes in soil organic carbon stocks and soil quality: land-use system effects in northern Ethiopia
G. Girmay 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):519-530
Abstract In Tigray, Ethiopia, land degradation is a dominant environmental problem and hence the regional government has undertaken restoration measures on degraded soils since 1991. The present study was aimed to assess the impact of land uses and soil management practices on soil properties, and consequently on soil quality of degraded soils. The catchments selected were Maileba and Gum Selassa, and land uses included cultivated (CL), grazing (GL), plantation (PA) and area exclosure (AE). Replicated soil samples were collected from topsoil and profiles of four land-use types in both catchments. Soils in area exclosure showed higher soil organic carbon (SOC), total N and extractable K than grazing land, cultivated land and plantation area mainly at 0–40 cm soil depth. Estimated soil organic carbon stock at Maileba in 0–40 cm depth varied between 54 to 74 Mg C ha?1, being lowest in cultivated land and highest in area exclosure, and the soil organic carbon stock in area exclosure represents 63% of total carbon stock stored in the profile. Soil organic carbon stock (0–40 cm) at Gum Selassa ranged between 33 to 38 Mg C ha?1, being higher in cultivated land and lower in plantation area. Soil quality index (SQI) of area exclosure (0.794) at Maileba and cultivated land (0.721) at Gum Selassa scored highest among all land uses, and the order was area exclosure>grazing land>plantation area>cultivated land at Maileba and cultivated land>grazing land>plantation area at Gum Selassa, highlighting the effectiveness of area exclosure in restoring soil quality of degraded soils. 相似文献
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[目的]揭示封育条件下土壤微生物及其土壤酶活性的适应机制,为退化草地恢复提供科学依据。[方法]采用蛇形布点法,采集封育0,3及11a伊犁绢蒿荒漠0—5,5—10,10—20cm土壤样品;采用常规方法对土壤有机质、过氧化氢酶活性、脲酶活性及土壤微生物数量进行测定。[结果]随封育年限增加,0—5cm土层有机质含量呈增加趋势,且封育11a较对照显著提高14.2%。土壤微生物组成中细菌数量最多,占绝对优势,放线菌次之,真菌最少。0—5cm土层细菌、真菌数量随封育年限增加呈降低趋势,放线菌数量呈增加趋势,至封育11a细菌、真菌较对照依次显著降低(47.3%,25.5%),而放线菌则显著增加(15.5%);5—20cm土层细菌数量变化不显著,而放线菌及真菌数量多呈增加趋势。封育对伊犁绢蒿荒漠0—20cm土层过氧化氢酶活性影响不显著,而0—10cm土层脲酶活性随封育年限增加呈增加趋势,10—20cm土层则呈降低趋势。[结论]长期封育有利于土壤有机质的积累,促进表层土壤放线菌数量及脲酶活性的增加。 相似文献
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In the northern highlands of Ethiopia, establishment of exclosures to restore degraded communal grazing lands has been practiced for the past three decades. However, empirical data on the effectiveness of exclosures in restoring degraded soils are lacking. We investigated the influence of exclosure age on degree of restoration of degraded soil and identified easily measurable biophysical and management‐related factors that can be used to predict soil nutrient restoration. We selected replicated (n = 3) 5‐, 10‐, 15‐, and 20‐year‐old exclosures and paired each exclosure with samples from adjacent communal grazing lands. All exclosures showed higher total soil nitrogen (N), available phosphorus (P), and cation exchange capacity than the communal grazing lands. The differences varied between 2·4 (±0·61) and 6·9 (±1·85) Mg ha−1 for the total N stock and from 17 (±3) to 39 (±7) kg ha−1 for the available P stock. The differences in N and P increased with exclosure age. In exclosures, much of the variability in soil N (R2 = 0·64) and P (R2 = 0·71) stocks were explained by a combination of annual average precipitation, woody biomass, and exclosure age. Precipitation and vegetation canopy cover also explained much of the variability in soil N (R2 = 0·74) and P (R2 = 0·52) stocks in communal grazing lands. Converting degraded communal grazing lands into exclosures is a viable option to restore degraded soils. Our results also confirm that the possibility to predict the changes in soil nutrient content after exclosure establishment using regression models is based on field measurements. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
14.
Livestock grazing is one of the most important factors influencing the soil nutrients, soil surface, vegetation diversity, and the above-ground biomass production in a natural rangeland ecosystem. An experiment was conducted to evaluate the influence of the long-term grazing on soil pH, electrical conductivity (EC), total organic carbon (TOC), total nitrogen (TN), available phosphorus (Available P), exchangeable potassium (Exchangeable K), diversity and the above-ground biomass production. This study was conducted in Maraveh Tapeh hilly rangelands of Golestan province, Iran. Soil and vegetation samplings were conducted based on the randomized systematic method. Three 150 m transects were positioned randomly within each grazing management practice. Soil samples were systematically taken every 3 m along each transect. Thirty (30) randomly chosen quadrats were sampled in each transect for vegetation diversity and biomass assessment. The effects of grazing management practices and aspect on soil nutrients, vegetation diversity, and biomass production were detected by analysis of variance (ANOVA) (at α = 0.05). Results of this study indicated, Exclosure north aspects had the maximum soil pH. There were significant differences found between soil electrical conductivity values in the grazed south aspect and the other treatments. Soil TOC, TN, available P and exchangeable K values increased significantly in the exclosure north aspects. Shannon diversity index and the above-ground biomass production had highest values in the exclosure north aspects. 相似文献
15.
黄土丘陵区深层干化土壤中节水型修剪枣树生长及耗水 总被引：4，自引：1，他引：3
黄土丘陵区人工林地深层土壤干层是否影响后续植物的生长是众多学者关心的热点。该文在砍伐23 a生旱作山地苹果园地后休闲4 a又栽植枣树,连续3 a观测干化土壤中枣树的生长及土壤水分变化,研究采用节水型修剪的再植枣林的生长及耗水情况。结果表明,前期23 a生苹果园地已使0~1 000 cm深土壤干化,休闲4 a后0~300 cm土层水分得到恢复,300~500 cm范围为中度偏重亏缺,500~700 cm为中度亏缺,700~1 000 cm为轻度亏缺;3龄枣树时开始采取节水型修剪,0~300 cm土层有效水分被消耗34.97%,至4龄时0~300 cm范围内前期恢复的土壤水分已消耗殆尽;在此情况下采取节水型修剪的枣树仍可保持良好生长,产量及其水分利用效率均高于相同水分条件下的常规修剪枣树,产量可达正常水分条件下枣树的1.39倍以上,产量水分利用效率可达1.52倍以上。研究结果证明节水型修剪是半干旱区深层干化土壤中枣树克服雨量不足和土壤水分亏缺的一条有效途径。 相似文献
16.
Grazing and over-grazing may drive changes in the diversity and functioning of below-ground meadow ecosystems.A field soil survey was conducted to compare microbial biomass carbon (Cmin) and soil fauna communities in the two main grassland management systems in subalpine regions of Yunnan Province,China:perennial grazing currently practiced due to increasing herd sizes and traditional seasonal grazing.A three-year exclosure experiment was then conducted to further compare the effects of different grazing practices,including treatments of no mowing,perennial grazing (NM + G),mowing followed by seasonal grazing (M + G),mowing and no grazing (M + NG),and no mowing or grazing (NM + NG).The comparative survey result revealed that Cmin and total density of soil fauna were significantly lower at a perennially grazed site than at a seasonally grazed site.The experiment results showed that in comparison to non-grazing treatments (M + NG and NM + NG),grazing (NM + G and M + G) reduced total fauna density (by 150 individuals m-2) and the number of taxonomic groups present (by 0.32 taxa m-2).Mowing decreased Cmin (by 0.31 mg g-1).Furthermore,the NM + G treatment (perennial grazing) had the lowest density of Collembola (16.24 individuals m-2),one of the two most common taxonomic groups,although other taxonomic groups responded differently to the treatments.Treatment effects on soil fauna were consistent with those on above-ground grasses,in which C:N ratios were greatly reduced by grazing,with this effect being the greatest for the NM + G treatment.In contrast,different grazing treatments had little effect on C:N ratio of soil.Furthermore,the traditional grazing method (mowing followed by seasonal grazing) may have less severe effects on some taxonomic groups than perennial grazing.Therefore,an appropriate management should aim to protect soil fauna and microbes in this area from over-grazing and against further degradation. 相似文献
17.
Khatab Abdalla Macdex Mutema Pauline Chivenge Colin Everson Vincent Chaplot 《Soil Use and Management》2022,38(2):1250-1265
Restoration of degraded grasslands through improved management is among the possible sustainable solutions to compensate for anthropogenic soil carbon (C) emissions. While several studies have shown a positive effect of rehabilitation on soil C, the impact on soil CO2 emissions is still uncertain. Therefore, this study aimed at quantifying the impact of grassland rehabilitation on soil CO2 emissions in a degraded grassland, South Africa. Commonly used rehabilitation practices were considered, that is rotational grazing (RG), livestock exclosure with fertilizer application (EF) and annual burning (AB), all being compared with traditional free grazing (FG). A total of 2880 in situ measurements of CO2 emissions were performed over 2.5 years under field conditions simultaneously with aboveground biomass, soil temperature, water content and soil organic C (SOC) to understand the changes in C fluxes. The RG performed the best under degraded grasslands by decreasing net CO2 emissions (per g of C) by 17% compared to FG, while EF increased emissions by 76% and AB had similar emissions to FG. The lower net emission under RG is associated with an increase in SOC stocks by 50% and aboveground biomass by 93%, after three years of implementation. Soil CO2 emissions were correlated positively to aboveground biomass and topsoil temperature (r = 0.91 and 0.60, respectively), implying a high effect of grass cover on soil microclimate and microbial activity. These results suggested RG as a potential cost-effective nature-based soil management strategy to increase SOC stocks into degraded grassland. However, long-term trials replicated in different environments are still required. 相似文献
18.
中国中亚热带荒漠化及其防治 总被引：3，自引：0，他引：3
我国中亚热带在自然条件下不会荒漠化。毁林开荒引起的严重水土流失是荒漠化产生、发展的罪魁祸首。荒漠化治理的根本途径是迅速恢复植被。对岩溶区行之有效的方法是进行长期的封禁治理,同时辅以人工补播、补植,且初期只能是灌草;对紫色土,应在水保造林基础上全面封禁;对丘陵红壤区,须通过人工种植重建植被并辅以封禁治理,首选树种是油茶;对低山红壤区,人工造林与封禁治理并举,有望5～10年取得成效;对岷江上游干旱河谷区,应在封禁基础上人工直播灌草,退耕地上也只能栽培灌丛保土。 相似文献
19.
Human‐caused trampling that results from excessive recreational use has caused damage to soil and vegetation in forest ecosystems in the Belgrad Forest of Istanbul. The objectives of this study were to examine effects of exclosure on selected soil properties and to determine the recovery time required for soil characteristics in a broadleaf forest recreation site. Litter biomass and topsoil (0–15 cm) were sampled in the forest, exclosure and recreational sites, and soil samples were analysed for saturation capacity, permeability, bulk density, total porosity, organic matter, root biomass, electrical conductivity and soil pH. Results showed that saturation capacity, permeability, total porosity and organic matter increased whereas bulk density decreased significantly in the topsoil under the exclosure, and all these soil properties in the topsoil of the exclosure were greater than those of recreational site. When effects of main factors were compared, averaging over sampling year and soil sampling depth, soils from the exclosure had significantly greater saturation capacity, permeability, total porosity, organic matter and litter biomass and lower bulk density values than the soils from recreational site. Six years of exclosure was effective in improving most of the soil properties in the topsoil. When topsoil and subsoil are considered together, it is obvious that a longer time period is needed for soil recovery in the forest recreational sites. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
20.
Influences of continuous grazing and livestock exclusion on soil properties in a degraded sandy grassland, Inner Mongolia, northern China 总被引：10，自引：0，他引：10
Overgrazing is one of the main causes of desertification in the semiarid Horqin sandy grassland of northern China. Excluding grazing livestock is considered as an alternative to restore vegetation in degraded sandy grassland in this region. However, few data are available concerning the impacts of continuous grazing and livestock exclusion on soil properties. In this paper, characteristics of vegetation and soil properties under continuous grazing and exclusion of livestock for 5 and 10 years were examined in representative degraded sandy grassland. Continuous grazing resulted in a considerable decrease in ground cover, which accelerates soil erosion by wind, leading to a further coarseness in surface soil, loss of soil organic C and N, and a decrease in soil biological properties. The grassland under continuous grazing is in the stage of very strong degradation. Excluding livestock grazing enhances vegetation recovery, litter accumulation, and development of annual and perennial grasses. Soil organic C and total N concentrations, soil biological properties including some enzyme activities and basal soil respiration improved following 10-year exclusion of livestock, suggesting that degradation of the grassland is being reversed. The results suggest that excluding grazing livestock on the desertified sandy grassland in the erosion-prone Horqin region has a great potential to restore soil fertility, sequester soil organic carbon and improve biological activity. Soil restoration is a slow process although the vegetation can recover rapidly after removal of livestock. A viable option for sandy grassland management should be to adopt proper exclosure in a rotation grazing system in the initial stage of grassland degradation. 相似文献