奇台荒漠草地自然保护区典型植物群落物种多样性分析

以重要值为测度指标,选择反映群落物种多样性、丰富度、优势度和均匀度的7个测定指数对奇台荒漠草地自然保护区荒漠植物群落物种多样性进行了研究。结果表明:在整个研究区荒漠植物群落中,白梭梭、梭梭、碱蓬、琵琶柴、沙蓬、驼绒藜和沙漠娟蒿等物种有较高的重要值。依据群落外貌结构和植物种类组成等特征,按照样方中建群种和优势种的重要值,将研究区植物划分为14个典型群落,各群落类型的物种多样性指数(Shannon-wiener指数H′)的顺序为:梭梭+角果藜(2.0740)>白梭梭+驼绒藜(1.9037)>白梭梭+羽毛三芒草(1.8909)>梭梭+芦苇(1.8474)>梭梭+雾冰藜(1.7434)>芦苇+猪毛菜(1.7278)>梭梭+白茎娟蒿(1.6723)>白梭梭+琵琶柴(1.5410)>白梭梭+沙蓬(1.4886)>白梭梭+假木贼(1.4530)>梭梭+碱蓬(1.4437)>白梭梭+刺木蓼(1.4277)>白梭梭+角果藜(1.3637)>白梭梭+沙漠娟蒿(1.3362)。     

奇台荒漠草地自然保护区主要植物种生态位特征研究

采用Levins公式和王刚生态位计测方法,分析了奇台荒漠草地自然保护区16种植物在土壤pH值,土壤总盐含量和土壤有机质维上的生态位宽度和生态位重叠.结果表明,按照各资源维上生态位宽度的平均值大小可以把16种植物分成3类,第一类群的物种是该荒漠区植物群落中的建群种,对荒漠环境有很好的适应性,包括白梭梭(0.421)、沙拐枣(0.458)、角果藜(0.641)、琵琶柴(0.569)等;第二类群的物种对环境的适应能力较弱,物种有沙蓬(0.326)、对节刺(0.304)、旱麦草(0.221);第三类群的对沙漠的适应能力较弱,生态位平均值均小于0.2,包括盐穗木、梭梭、猪毛菜、假木贼和驼绒藜。优势种的生态位宽度越大相应的生态位重叠值也越大,存在一定的线性关系,表明优势种在对荒漠的环境适应上都趋于相似性。     

琵琶柴和沙拐枣茎的木质部结构的差异性及空间变异特征

木质部结构性状是植物适应不同水分条件的基础,也是植物响应环境条件变化的核心属性之一。以西北荒漠区的典型灌木琵琶柴(Reaumuria soongarica)和沙拐枣(Calligonum mongolicum)为研究对象,对其木质部结构和水力功能性状进行对比分析,以期了解同一生境中不同物种的差异性或相似性,以及同一物种在不同环境条件下的木质部结构性状的可塑性。结果表明：（1）琵琶柴和沙拐枣的木质部结构性状存在显著差异,沙拐枣平均导管直径、脆弱性指数显著高于琵琶柴,而导管密度、导管分组指数则相反。（2）琵琶柴和沙拐枣的木质部结构性状随气候变化的规律具有差异,随年均降水量和干旱指数的增加,沙拐枣的平均导管直径与导管厚跨比显著下降,而琵琶柴的平均导管直径与导管厚跨比与之无关,仅理论导水率与年均降水量和干旱指数呈显著正相关关系。（3）琵琶柴木质部导水系统存在效率与安全的权衡,而沙拐枣中没有表现出效率和安全的权衡关系。（4）性状网络分析结果表明,琵琶柴和沙拐枣的中心性状均为平均导管直径,平均导管直径的变化介导了性状网络的变化。琵琶柴和沙拐枣的木质部结构性状存在显著差异,相对于沙拐枣,琵琶柴水分利...     

驼绒藜属植物蒸腾作用的某些特征

采用快速称重法测定了驼绒藜属 ( Ceratoides)植物 3个种 5个生态型蒸腾速率和失水率叶片离体 1 2分钟内的连续变化。结果发现 ,分段蒸腾速率 ( STR)和分段失水率 ( SDR)表现为无规则律动模式 ,其变幅和节奏具有不可预知性 ;平均蒸腾速率 ( ATR)表现为曲率较小的相对平滑的抛物线。ATR的线性分布较好地体现出植物间蒸腾速率调节能力的差异。华北驼绒藜的 2个生态型和驼绒藜宁夏生态型蒸腾作用的调节能力较强 ,而来自新疆的心叶驼绒藜和驼绒藜新疆生态型调节能力则较弱。不同植物 ATR的线性参数对温度、相对湿度和光照强度的敏感性差异很大。     

塔克拉玛干沙漠腹地10种灌木光合器官的滞尘能力评价

通过全株光合器官取样,利用质量差减法,对塔中植物园10种灌木的滞尘能力进行多指标比较。结果表明：① 植物光合器官滞尘量与所处环境条件有关,在沙漠地区同种植物光合器官滞尘量大于沙漠以外区域。② 梭梭和沙拐枣的光合器官退化为同化枝,形态类似针叶树种的针叶,但尚有极度退化的叶片,其滞尘量大于其他区域针叶树种;与沙拐枣相比,梭梭同化枝节间距较短,叶片数量相对较多,因此梭梭的滞尘能力大于沙拐枣。③ 柽柳属植物虽然叶片也极度退化,但具有数量众多、分布密集、被覆绒毛、分泌盐分等特性,而且树冠光合器官密度大,具有很强的滞尘能力,光合器官滞尘量大于梭梭和沙拐枣,也大于阔叶灌木和阔叶乔木;由于光合器官表面滞尘特性、叶片数量以及树冠光合器官密度的差异,柽柳属植物光合器官滞尘能力也存在种间差异。④ 全植株光合器官滞尘量、单位重量光合器官滞尘量、单位表面积光合器官滞尘量都只能从一个侧面反映植物光合器官的滞尘能力,而单位树冠体积的光合器官滞尘量则可较全面地反映植物光合器官的滞尘能力。以单位体积树冠空间光合器官滞尘量为评价指标,10种灌木光合器官滞尘能力的排序为：甘蒙柽柳>长穗柽柳>华北柽柳>紫杆柽柳>刚毛柽柳>多花柽柳>多枝柽柳>沙生柽柳>梭梭>头状沙拐枣。     

阿拉善荒漠几种典型灌木种子水分响应与繁殖对策研究

本文以阿拉善荒漠分布的沙冬青(Ammopiptanthus mongolicus)、梭梭(Halox-ylon ammodendron)、红砂(Reaumuria soonorica)、阿拉善沙拐枣(Calligonum alaschanicum)、膜果麻黄(Ephedra przewalsetina)、绵刺(Potaninia mongolica)和四合木(Tetreana mongol-ica)等灌木为研究对象,以种子吸胀过程中对水分的吸收速度和水分利用效率作为对水分的响应特性。研究结果表明:所供实验的各种灌木种子吸胀所需时间顺序依次为:梭梭<四合木<绵刺<膜果麻黄<红砂<阿拉善沙拐枣<沙冬青,与之相对应的种子千粒重为沙冬青>阿拉善沙拐枣>红砂>梭梭>四合木>膜果麻黄>绵刺,种子千粒重与吸胀时间呈极显著的正相关关系;吸胀过程中水分吸收速度和水分利用效率分别是阿拉善沙拐枣>沙冬青>四合木>红沙>梭梭>绵刺>膜果麻黄,梭梭>膜果麻黄>绵刺>四合木>阿拉善沙拐枣>沙冬青>红沙。响应于荒漠水分的变化,荒漠灌木可分为对水分敏感性植物和迟钝性植物。对水分敏感性植物,繁殖对策表现为典型的r-对策,千粒重较小,对水分利用效率较高,如绵刺、梭梭等,对水分迟钝性植物,繁殖对策为典型的k-对策,千粒重较大,水分利用效率较低,如阿拉善沙拐枣和沙冬青等。响应于荒漠环境为极度胁迫下的易变环境,水分敏感的植物对荒漠植被的稳定具有重要贡献,响应于相对稳定时间尺度内,水分迟钝植物对荒漠植被构建起着关键作用。这种r-对策和k-对策荒漠灌木对水分不同的利用方式和繁殖方式,既能在干旱多变的气候环境变化下保持一定的荒漠景观植被,又能在稳定气候环境下保持另一种荒漠景观植被,从而确保荒漠地表环境的稳定。     

腾格里沙漠红卫地区固定沙丘上固沙灌木种群空间分布格局与空间关联性研究

种群空间分布格局和关联性的研究对预测群落演替趋势和植被重建具有重要意义.基于腾格里沙漠天然植被区红卫地区固定沙丘上三种优势半灌木或灌木种群(油蒿(Artemisia ordosica)、柠条(Caragana korshinskii)和驼绒藜(Ceratoides latens))个体的位置和生长发育阶段信息,研究了三...     

克拉玛依植物群落结构和物种多样性研究

采用多样性指数,丰富度指数和均匀度指数对克拉玛依植物群落物种多样性进行了研究。结果表明:各群落类型的物种多样性指数的顺序为:梭梭+碱蓬>花花柴、胡杨>碱蓬+麻黄>柽柳>琵琶柴>猪毛菜>梭梭>芦苇>盐节木>白刺+柽柳;灌木和乔木群落多样性指数和丰富度指数大于草本群落,而均匀度指数在乔木,灌木和草本群落中则表现出多样化的趋势。     

古尔班通古特沙漠南缘优势物种的种间关联特征

基于古尔班通古特沙漠南缘植物多样性的调查,对22个优势物种间的关联性进行了分析。结果表明:231个种对中,正关联种对数(141对)多于负关联种对(90对),且前者达到显著关联的种对数(89对)也多于后者(27对)。乔灌木对草本植物分布具有显著影响,形成种对中正关联种对数(44对)多于负关联种对(28对),且前者达到显著关联的种对数(22对)也多于后者(10对)。其中白梭梭、白茎绢蒿和淡枝沙拐枣分别与18个优势草本中的11个、13个和13个呈正关联,且多为显著关联;但梭梭与这些草本均不存在显著正关联,表现出明显的生境趋异性。绝大部分(211对)种对的OI<0.6,处于中等偏弱联结强度,表明干旱环境胁迫使部分物种在资源利用趋同同时,而不同物种集团之间发生了空间分布的分离。DCA排序图的种间距离和分布位置在一定程度上印证了上述结果。研究认为本沙漠白梭梭、白茎绢蒿和淡枝沙拐枣等灌木不仅具有防风固沙效应,而且对草本具有重要的看护效应,需要重点保护。在人工植被恢复过程中,应重视不同乔灌木与草本植物间的合理搭配,以构成灌木-草本群落,形成立体防风固沙体系,更好地发挥生态效应。     

中国特有种-奇台沙拐枣(Calligonum klementzii)群落特征及其异地建植模式初探

对奇台沙拐枣(Calligonum klementzii)自然植物群落特征进行了调查分析,依据自然植物群落特征对异地重建模式进行了探讨。结果表明:(1)自然群落特征数量指标中,优势度、重要值、多度、频度、高度、生活型、生长型是决定重建群落特征的主要参考指标。(2)奇台沙拐枣重建植物群落理论最小种植面积为2286-2857m2;主要物种数为10种,其中小乔木2种,灌木3种,草本5种;重建群落优势种奇台沙拐枣、梭梭(Haloxylon mmodendron)、羽状三芒草(Aristida pennata)最小物种保存数分别为96-120株、40-80株、120-240株;种群年龄结构按自然群落模式配置。     

民勤绿洲人工梭梭林群落结构及种群生态特征

采用野外样方调查方法,分别对生长于民勤绿洲盆地不同立地类型的人工梭梭群落内的物种重要值、多样性等生态特征进行分析,将其划分为3个类型：梭梭-一年生植物群聚、梭梭-一年生植物-灌木群聚和梭梭-灌木群落;分别分布于流动沙丘、半固定沙丘和固定沙地上,随着沙地固定程度的增加,人工梭梭群落由梭梭-一年生植物群聚（先锋群落,盖度23%、多样性指数0.26）演替到梭梭-一年生植物-灌木群聚（盖度30%、多样性指数0.34）再演替到梭梭-灌木群落（盖度40%,多样性指数0.60）;在人工梭梭群落演替过程中,人工梭梭种群在不同沙地类型上生长状况不同,沿着流动沙地→半固定沙地→固定沙地为衰退型,这种衰退与土壤水分的含量有关。     

不同植被覆盖度沙垄土壤化学性质的空间分异

为了研究温带固定半固定沙漠土壤化学性质与地表植被的关系,本文以古尔班通古特沙漠西南缘莫索湾地区沙漠–绿洲过渡带为研究区,分别选取植被覆盖度为10%和15%的半固定沙垄及植被盖度为30%的固定沙垄。采集了各沙垄不同地貌部位的土壤样品,室内测试了土壤pH、电导率、有机质、全氮和全磷等指标。结果表明：① 随着植被覆盖度下降,沙垄西坡、坡顶和东坡,土壤pH、电导率、有机质、全氮和全磷呈逐渐降低趋势;② 不同地貌部位的分布格局各沙垄表现不一致,沙垄A和沙垄B的 pH、电导率、有机质、全氮和全磷含量最大值均出现在垄间地,其他部位之间没有明显的规律,沙垄C 的pH和电导率最大值出现在垄间地,而土壤养分含量于坡顶部位富集;③ 各沙垄不同土层土壤性质分布规律相对一致,土壤pH、电导率随着土层深度的增加呈上升的趋势,而土壤养分随着土层深度的增加而降低;④ 土壤化学性质空间分布异质性与植被的分布格局密切相关,相互影响,当植被覆盖度较高时,生物作用起主导作用,当植被覆盖度较低时,风蚀、地形等非生物因素作用加强,影响生物作用,植被对土壤颗粒和养分的拦截及富集作用逐渐减弱或消失。     

Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon mmodendron populations

Spatial heterogeneity is a ubiquitous feature in natural ecosystems,especially in arid regions.Different species and their discontinuous distribution,accompanied by varied topographic characteristics,result in soil resources distributed differently in different locations,and present significant spatial heterogeneity in desert ecosystems.In this study,conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations,Haloxylon persicum Bunge ex Boss.,which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C.A.Mey.) Bunge,which inhabits interdunes in the Gurbantunggut Desert of Xinjiang,China.The results showed that soil pH,electrical conductivity (EC),soil organic carbon (SOC),available nitrogen (AN) and available phosphorus (AP) were significantly higher in H.ammodendron populations than that in H.persicum.The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10%＜CV＜100%) except pH in both plots,(2) the variability of soil pH,EC and AP in H.ammodendron populations was higher than that in H.persicum populations,and (3) SOC and AN in H.ammodendron populations were lower than that in H.persicurn populations.Geostatistical analysis revealed a strong spatial dependence (Co/(Co+C)＜25%) within the distance of ranges for all tested parameters in both plots.The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution,individual size of plants,and the topographic features,especially with the plants nearest to sampling points and the topographic features.In each plot,soil EC,SOC,AN and AP presented similar distributions,and fertile islands and salt islands occurred in both plots but did not affect every individual plant,since the sampling distance was larger than the size of such fertile islands.The results of topographic effects on soil heterogeneity suggested significant differences between the interdunes and dune-tops.Different topographic characteristics (physical factors) between plots result in the differences in SOC,AN and AP,while the heterogeneity of soil pH and EC arise from plant species and their distribution (biotic factor).Such biotic and physical factors did not occur in isolation,but worked together on soil heterogeneity,and played important parts in improving the soil properties.Hence these factors were ecologically valuable in the highly resource-stressed arid study area.     

不同植被覆盖度沙垄土壤化学性质的空间分异

为了研究温带固定半固定沙漠土壤化学性质与地表植被的关系,本文以古尔班通古特沙漠西南缘莫索湾地区沙漠-绿洲过渡带为研究区,分别选取植被覆盖度为10%和15%的半固定沙垄及植被覆盖度为30%的固定沙垄。采集了各沙垄不同地貌部位的土壤样品,室内测试了土壤pH、电导率、有机质、全氮和全磷等指标。结果表明:①随着植被覆盖度下降,沙垄西坡、坡顶和东坡,土壤pH、电导率、有机质、全氮和全磷呈逐渐降低趋势;②不同地貌部位的分布格局各沙垄表现不一致,沙垄A和沙垄B的pH、电导率、有机质、全氮和全磷含量最大值均出现在垄间地,其他部位之间没有明显的规律,沙垄C的pH和电导率最大值出现在垄间地,而土壤养分含量在坡顶部位富集;③各沙垄不同土层土壤性质分布规律相对一致,土壤pH、电导率随着土层深度的增加呈上升的趋势,而土壤养分随着土层深度的增加而降低;④土壤化学性质空间分布异质性与植被的分布格局密切相关,相互影响,当植被覆盖度较高时,生物作用起主导作用,当植被覆盖度较低时,风蚀、地形等非生物因素作用加强,影响生物作用,植被对土壤颗粒和养分的拦截及富集作用逐渐减弱或消失。     

Species composition and diversity,and carbon stock in a dune ecosystem in the Horqin Sandy Land of northern China

In this study, we determined carbon allocation and carbon stocks in the plant-soil system of different dune ecosystems in northeastern China. We quantified the species composition, above- and below-ground biomasses, and carbon stocks of three dune types(i.e. active dunes, semi-stabilized dunes and stabilized dunes) and their corresponding inter-dune lowlands(i.e. interdune lowlands of active dunes, interdune lowlands of semi-stabilized dunes and interdune lowlands of stabilized dunes) in the Horqin Sandy Land. The results showed that the succession series on interdune lowlands of the Horqin Sandy Land confirmed differences in species composition of the various dune types. Aboveground carbon(AGC) on the interdune lowlands of semi-stabilized dunes(33.04 g C/m2) was greater(P<0.05) than that on the interdune lowlands of active dunes(10.73 g C/m2). At the same time, the different dune types did not show any significant differences(P>0.05) in belowground plant carbon(BGC). However, the percentage of plant BGC in interdune lowlands of active dunes(81.5%) was significantly higher(P<0.05) than that in the interdune lowlands of semi-stabilized dunes(58.9%). The predominant carbon pool in the study dune ecosystem was in the soil. It accounted for 95% to 99% of total carbon storage. Soil organic carbon(SOC) was at least 55% greater(P<0.05) in the interdunes than in the dunes. Stabilized dunes showed at least a 37% greater(P<0.05) SOC content than active dunes up to a 1-m soil depth. Meanwhile, SOC content of interdune lowlands of semi-stabilized dunes was greater(P<0.05) than that of interdune lowlands of active dunes only up to a 20-cm soil depth. The dune ecosystem showed a great potential to store carbon when interdune lowlands of active dunes were conversed to interdune lowlands of semi-stabilized dunes, which stored up to twice as much carbon per unit volume as interdune lowlands of active dunes.     

策勒绿洲-沙漠过渡带不同植被沙丘表面风沙沉积物粒度特征分析研究

通过对策勒绿洲-沙漠过渡带不同植被类型下沙丘表层风沙沉积物粒度分布特征进行研究,探讨不同荒漠植被类型下风沙沉积物的沉积规律。结果表明:胡杨、骆驼刺、柽柳、花花柴灌丛沙堆表层沉积物粒级组成均以极细砂(57.20%-60.37%)为主,其次为极粗粉砂(18.47%-21.34%)和细砂(16.56%-19.03%),骆驼刺灌丛沙堆表面整体风沙沉积物平均粒径最细(84.06μm),胡杨沙堆表面整体沙物质平均粒径最粗(88.88μm)。四种植被沙堆表面沙物质的分选性总体上在中等-较好水平,分选系数介于1.44-2.02之间,胡杨沙堆表层沙物质的偏度值在顶部附近属于极负偏,骆驼刺、柽柳、花花柴灌丛沙堆表面沙物质均为负偏。峰度值介于0.95-1.51之间,胡杨沙堆顶部附近及骆驼刺沙堆表层沙物质主要属于窄峰态,柽柳、花花柴沙堆表面沙物质属于中等峰态。沙物质平均粒径与偏度值呈极显著正相关性(p<0.01),沙物质的分选系数与峰度值呈极显著正相关性,沉积物粒度特征空间差异主要受物源、植被高度、冠型、疏透度等因素影响。     

沙漠油田基地路生物防沙试验段林木生长状况

对沙漠油田基地路生物防沙技术示范工程中不同立地条件下所种植的梭梭、柽柳、沙拐枣三类灌木的生长状况进行了调查，对盐水灌溉后各种立地类型的沙地土壤水盐状况进行了取样分析。研究结果表明：在塔中沙漠油田基地路生物防护体系建设的过程中，在沙丘和平沙地上应选用沙拐枣和梭梭，如种植柽柳则需采取适当的土壤保水措施（如在种植坑内加施草碳、固水剂、粘土等）。在含有下伏亚粘土层的沙地上应选用柽柳和梭梭，在丘间板结沙地上要想营造防护林，必需采取适当的技术措施，使土壤疏松（如深开沟、回填流沙等）。     

Grain size distribution at four developmental stages of crescent dunes in the hinterland of the Taklimakan Desert,China

Although scientists have performed many studies on crescent (barchan) dunes in the Taklimakan Desert,few studies reported the changes in grain size at different development stages of crescent dunes.In order to evaluate the changing trends of surface sediment grain size with dune development,we investigated the grain size characteristics at four developmental stages (oval sand pile,shield dune,incipient crescent dune and mature crescent dune) of crescent dunes by measuring the morphology of sand dune and observing the near-surface wind regime.The dunes have developed in a wide inter-dune corridor between high compound longitudinal ridges in China's Taklimakan Desert.The surface sediments at four developmental stages of the crescent dunes were primarily composed of fine sands,followed by very fine and medium sands.Mean grain sizes ranged from 2.8 to 3.1 φ,with a unimodal distribution.The sands were moderately well-sorted,their distribution varied from platykurtic to very platykurtic,and symmetrical or skewed towards the fine particles.From oval sand piles through shield and incipient crescent dunes to mature crescent dunes,incipient grain size gradually increased,particles became finer,sorting became better,kurtosis and skewness increased.Grain sizes on the surface layer became coarser upwards from the toe of the windward slope and then became finer towards the bottom of the leeward slope.We found that the coarsest particles at different positions at the four developmental stages were different.The coarsest particles were distributed at the top of the oval sand piles and shield dunes,versus at the middle of the windward slope of the incipient and mature crescent dunes.Correlations between the mean grain size and other grain size parameters showed that as mean grain size became finer,sorting became better and kurtosis became wider,but skewness changed only slightly.In addition,grain size variation in the surface sediments correlated with the movement speed of the dunes in the study area.In the open ground among tall-complex longitudinal ridges in the hinterland of the Taklimakan Desert where aeolian environment is characterized by comparatively strong wind and unsaturated sand flow,faster dune movement corresponded to coarser grain size.     

Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon ammodendron populations

Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% < CV < 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) < 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested s     

两种梭梭出苗对生境土壤基质互换与沙埋深度的响应

以梭梭（Haloxylon ammodendron）、白梭梭（Haloxylon persicum）两种植物为研究对象,采用生境土壤基质互换种植和盆栽控制沙埋深度方法,对其萌发出苗和幼苗建成进行对比研究。结果表明：丘间低地土壤pH、电导率和养分含量均显著高于沙丘顶部,其中电导率（可溶盐含量）相差达5倍;土壤含水量差别不...