沙拐枣幼苗生长规律及与其抗旱性关系研究

本文对典型的旱生植物沙拐枣当年新生幼苗在其自然干旱生境下地下部分与地上部分的生长量，水分和干物质含量及其变化和碳水化合物含量的变化进行了持续性研究，对其幼苗生长规律，地下部分与地上部分的关系及与植株整体旱性的关系进行了探讨。试验结果幼苗根的生长，尤其在发育初期对植株抗旱性的建立有重要作用。     

兰州市南北两山造林树种的生长过程解析

兰州市南北两山的绿化是为当地居民营造良好居住环境的重要工作,该地区造林树种生长规律更是植被恢复中树种选择和抚育管理的依据。以2005年在兰州市甲子坪1号和2号试验地以及2006年在皋兰山试验地栽植的侧柏和山杏为对象,通过树高和胸径调查以及树干解析,对其生长特性进行研究。结果表明:在2014年调查时,甲子坪1号和2号试验地以及皋兰山试验地的侧柏平均树高分别为3.0 m、3.7 m和3.0 m,平均胸径分别为3.5 cm、5.2 cm和3.0 cm,侧柏的存活率为80%~88%,山杏的存活率达到80%以上。2008—2014年的3次调查结果表明,侧柏的树高平均增长量为0.15~0.18 m·a~(-1),山杏的树高平均增长量为0.17~0.20 m·a~(-1)。对侧柏优势木(树高4.5 m)、平均木(树高3.5 m)和劣势木(树高2.8 m)的树干解析得出,侧柏苗期(栽植后3 a)的高生长速率为0.3~0.4 m·a~(-1),个体间没有显著差异,但造林3 a后优势木的高生长速率为0.2~0.4 m·a~(-1)、平均木为0.2 m·a~(-1)、劣势木为0.1~0.2 m·a~(-1),个体间差异显著。     

准噶尔盆地农田防护林树种青杨的生长规律研究

揭示杨树人工林在生长特性方面的变化规律对进一步挖掘杨树人工林的生产潜力和保证林木速生丰产具有十分重要的意义。以新疆准噶尔盆地农田防护林21a生青杨为研究对象,运用树干解析法对其树高、胸径、材积的生长规律进行调查研究。结果表明:青杨生长过程可以分为三个时期,第0～6a为幼树期,第7～15a为速生期,第16～21a为成熟期。树高速生阶段集中在第3～14a,胸径速生期为第6～16a,材积速生期为第7～15a。在胸径快速增长期间适当进行施肥管理,有利于培育优质大径材。青杨数量成熟年龄约为18a,初始防护成熟龄在第8a。建立的青杨树高、胸径和材积生长的六种模型:幂函数型、对数型、指数型、二/三次多项式回归型以及Logistic生长方程均取得较好的模拟效果(R2>0.809),三次多项式方程是模拟青杨树高和胸径生长进程的最佳模型,Logistic模型是模拟青杨材积生长进程的最佳模型。     

额济纳胡杨林生长规律及生物生产力的研究

本文利用34块胡杨林标准地获得的林分数量及质量指标,对额济纳胡杨林的生长规律和生物生产力及其与生态因子之间的关系进行了研究。结果表明胡杨生长具有明显的阶段性,不同的生态因子对胡杨的生物生产力具有不同的影响。     

小春作物田间杂草种类及生长规律调查研究

农村种植结构的调整、耕作制度的改变以及大面化学除草剂的使用,都使近年来农田杂草优势种群和群落结构发生了相应的变化.为掌握农田杂草种群结构和发生危害情况,给今后综合治理草害提供依据,我们于2000～2001年对本州大理、宾川、洱源和巍山等县的蚕豆、小麦、大蒜田杂草进行了调查,现将结果报道如下.     

科尔沁沙地榆树疏林草原植被研究

榆树疏林草原是温带典型草原地带、适应半干旱半湿润气候的隐域性沙地顶级植物群落 ,广泛分布于科尔沁沙地、浑善达克沙地 ,是防风固沙、保护沙区生态环境和周边土地资源的一种重要的植物群落类型 ,也是耐旱沙生植物的重要物种基因库和草原野生动物的重要避难所和栖息地。然而 ,由于人类的干扰 (如毁林开荒、过度放牧、甚至片面地建立人工林群落等 ) ,不同程度地破坏了榆树疏林的生态环境 ,影响了其特有的生态作用。遥感监测结果表明 ,分布在科尔沁沙地的榆树疏林草原总面积仅有 41 .4万 hm2 ,通常由乔木、草本或乔木、灌木、草本二个或三个层次构成 ,按疏林群落组成可分为白榆疏林草原、白榆疏林灌丛草原、大果榆疏林草原、大果榆疏林灌丛草原、白榆 +大果榆疏林草原和白榆 +大果榆疏林灌丛草原六种类型。榆树疏林草原的类型多样 ,结构复杂 ,具有多种经营利用方向 ,按照经营利用方向 ,可以划分为以下三种 : 型散生的榆树疏林草原 ,榆树稀疏地散生于沙地草原上 ,有效地保护着牧草的生长 ,同时也可以为放牧牲畜提供良好的庇护 ,属于放牧型疏林草地 ; 型团块状的榆树疏林草原 ,榆树多呈团块状分布 ,少则 3～ 5株 ,多则 1 0～ 2 0株构成一个团块 ,团块内榆树生长相对通直 ,可以成材利用 ,这种类型的草地具?     

梭梭生长对水分胁迫的响应规律研究

本研究旨在了解水分胁迫条件下准噶尔盆地梭梭的生长耗水规律,确定准噶尔盆地梭梭生态用水量.试验采用桶栽方法研究了梭梭在不同水分胁迫下的耗水规律、生长特性以及耗水和生长之间的关系.结果表明,水分胁迫程度越大,梭梭适应水分亏缺环境的过程越长.梭梭生长期最低耗水量为50 mm;当耗水量超过150mm时,其植株生长速度减慢;水分...     

科尔沁沙地的土地利用与沙漠化

根据1985年和2000年的土地利用数据和从相同时期的TM影像上提取的土地沙漠化数据,运用ARC/INFO软件和Access统计软件,分析科尔沁沙地近20年来土地利用和沙漠化土地的构成及变化特点、土地利用与土地沙漠化之间的关系。主要结论草地和耕地是土地利用的主要类型,未利用地面积较大,其它利用类型面积较小;15年来,耕地和林地增加幅度最大,草地减少幅度最大,土地利用转移的主要方向是草地变为耕地和林地。科尔沁沙地沙漠化土地比例大,占一半左右,以中度类型为主;变化趋势是沙化面积增加,程度减轻。在持续强度利用条件下,面积广大的草地和耕地发生退化,由潜在沙漠化土地发展为轻度和中度为主的沙漠化土地;而土地利用方式变化所形成的沙漠化土地面积较小,在新增沙漠化土地中的比例亦很小。所以,草地、耕地等土地利用强度的增大是沙漠化土地面积扩大的最主要原因,而土地利用方式的改变能加快土地沙漠化的进程。     

科尔沁沙地景观格局变化的研究

本文以1995年和2000年的遥感影像为信息源,利用GIS图像、数据处理功能,获取景观要素图斑,得出图斑的数量、周长、面积等特征,并根据景观生态学的原理和方法,计算研究地区的景观指数,通过对景观指数的分析,揭示该地区沙漠化现状及动态。结果表明,研究地区各种类型沙漠化土地总面积37.4万hm2,占总土地面积的39.1％;植被盖度小于30％的较严重沙漠化土地从1995年到2000年以61.0hm2/年的速度扩展;景观破碎度变大,反映出入类活动对景观的干预作用不断增强;沙漠化景观要素的形状指数变化表现出内、缘比变大,不利于沙漠化土地的自然恢复。研究地区沙漠化是一个发展的过程。     

盐池沙地主要灌木种的物候及生长规律研究

本文根据实验基地的实际现测数据,阐述了柠条、毛条、杨柴、花棒、沙柳、柽柳、沙木蓼等七种沙土灌木的物候及生长规律。     

Effects of rainfall patterns on annual plants in Horqin Sandy Land,Inner Mongolia of China

Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential responses of plants to the changes in rainfall regimes, such as rainfall intensity and duration, and length of dry intervals. In this study, we investigated the effects of different rainfall patterns(e.g. small rainfall event with high frequency and large rainfall event with low frequency) on biomass, growth characteristics and vertical distribution of root biomass of annual plants in Horqin Sandy Land, Inner Mongolia of China during the growing season(from May to August) of 2014. Our results showed that the rainfall patterns, independent of total rainfall amount, exerted strong effects on biomass, characteristics of plant growth and vertical distribution of root biomass. Under a constant amount of total rainfall, the aboveground biomass(AGB), belowground biomass(BGB), plant cover, plant height, and plant individual and species number increased with an increase in rainfall intensity. Changes in rainfall patterns also altered the percentage contribution of species biomass to the total AGB, and the percentage of BGB at different soil layers to the total BGB. Consequently, our results indicated that increased rainfall intensity in future may increase biomass significantly, and also affect the growth characteristics of annual plants.     

Land cover changes and the effects of cultivation on soil properties in Shelihu wetland,Horqin Sandy Land,Northern China

Land cover change plays an essential role in the alternation of soils properties.By field investigation and applying satellite images,land cover information in the Shelihu wetland was carried out in an area of 2,819 hm 2 in 1985,1995,2000,2005,2010 and 2011,respectively,in Horqin Sandy Land.A total of 57 soil sampling sites across Shelihu were chosen in wet meadow(CL0),cropland(CL) and sandy land(SL) according to the spatial characteristics of water body change.Soil texture,organic carbon(SOC),total nitrogen(TN) and total phosphorus(TP) contents,electrical conductivity(EC) and pH were measured at the soil depths of 0-10,10-20 and 20-40 cm to examine the influence of agricultural conversion and continuous cultivation on soil properties.The results showed that the study area was covered by water body in 1985,which gradually declined afterwards and then reclaimed rapidly at a mean annual rate of 132.1 hm 2 /a from wet meadow to cropland since 1995.In 2011,water body was drained and the area was occupied by 10.8% of CL0,76.9% of CL and 12.3% of SL.Large amounts of SOC,TN and TP were accumulated in the above depths in CL0.Soil in CL0 also had higher EC and silt and clay fractions,lower pH than in SL and CL.Soil in SL was seriously degraded with lower contents of SOC,TN and TP than in CL and CL0.SOC,TN content and EC in CL decreased with the increase of cultivation age,while pH showed a reverse trend with significance at plough horizon.The agricultural conversion in Shelihu was driven by the comprehensive factors of precipitation reduction,economic development and intense competitions for irrigation water.Continuous cultivation in this process is not sustainable because of SOC degradation and nutrient content reduction.The key point is that conventional tillage and removal of residuals induced further land degradation.Wetland reclamation for immediate economic interests led to greater costs in the long-term environmental restoration in Horqin Sandy Land.     

Plantations of native shrub species restore soil microbial diversity in the Horqin Sandy Land,northeastern China

Caragana microphylla Lam., a leguminous shrub species, plays an important role in revegetation in the degraded ecosystems of the Horqin Sandy Land, Northeastern China. Large areas planted with this shrub have been artificially established as sand binders for soil protection, which might change the composition of soil bacterial communities with the development of sand dune stabilization. In this paper, we investigated the diversity and composition of native soil bacterial communities in the C. microphylla plantation for sand fixation using polymerase chain reaction with denaturing gradient gel electrophoresis（PCR-DGGE） to understand the influence of this plantation on sandy soil ecosystem development. We collected soil samples from plantations with an age sequence of 0, 9, 16, and 26 years, as well as from the natural community, to identify the differences among soil bacterial communities. The result showed that bacterial abundance and community composition in the sandy land were affected by the age of the C. microphylla plantation. Moreover, bacterial diversity decreased with increasing plantation age, and the composition of the bacterial community in the 26-year plantation was similar to that in the natural community. Phylogenetic analysis of bands excised from the DGGE gels showed that members of alpha Proteobacterium, gamma Proteobacterium, Gemmatimonadetes and Chloroflexi were dominant in the sandy land. The stabilization of moving sand dune and development of sand-fixed plantation resulted in an increase of soil fertility, which could drive the structural evolvement of soil bacterial community, and it needs over 20 years for the soil bacterial community to form a stable structure, similar to the case for the natural vegetation.     

科尔沁沙质草地封育过程中的植被变化及其机制

对科尔沁沙地乌兰敖都地区的沙质草地封育后的植被变化及其机制进行分析研究。结果表明：① 围栏封育使植被物种丰富度、密度显著提高,群落的优势种发生明显变化;围封地的Simpson多样性指数和Shannon-Wiener多样性指数均表现为随封育时间增加而下降,而Pielou均匀度指数随围封时间增加表现出先增加后下降的趋势。② 围栏封育可以增加土壤表层（0~10 cm）的养分含量,但电导率随围封时间表现出先降低后增加的趋势,同时围栏封育使土壤水分含量下降。③ 土壤表层（0~10 cm）各因子对多样性的影响不同,全氮和pH与Pielou指数呈显著(P<0.05)负相关;全氮对于丰富度指数呈显著(P<0.05)正相关;其他土壤环境因子与多样性指数间关系均不显著,表明在沙质草地封育不利于植物多样性的维持,但有利于土壤养分的积累。     

近60年科尔沁沙地的气候变化

处于季风边缘带的科尔沁沙地气候变化具有复杂性和敏感性特征,文中采用线性倾向估计、非参数检验等方法探讨了其变化规律。结果表明:近60年研究区的年均气温呈上升趋势,变化速率为0.37℃/10a,尤其是20世纪80年代中后期以来增温趋势更为明显。且年际极端最高、最低气温也呈上升趋势。在季节变化中,春、冬季增温明显,夏季和秋季变化略小。而年降水量呈稳中有降的总趋势,变化速率为-13.54mm/10a。且年际、季节的降水日数也出现减少趋势。在季节变化中,除了春季以外其它季节均有减少趋势,与SPI变化一致。气温与降水量总体上呈负相关关系,即气温上升与降水的减少相对应,因而该区气候变化呈暖干化总趋势。夏季气候变化与东亚夏季风强弱有一定联系。     

Effects of vegetation cover on recruitment of Ulmus pumila L. in Horqin Sandy Land,northeastern China

Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Horqin Sandy Land, Inner Mongolia, northeastern China. We hyphothesized that(1) seed density(i.e., number/m2) increases as vegetation cover increases, and(2) there will be more surviving seedlings in locations with higher vegetation covers. Total vegetation cover and initial densities of seeds, germinated seeds and surviving seedlings of Ulmus pumilia were evaluated under various vegetation covers in trying to clarify the effects of vegetation cover on the early stages of the plant life history. In agreement with the first hypothesis, initial seed densities were greater(P<0.05) under higher vegetation covers. The relationship between vegetation cover and initial seed density was represented by a quadratic regression, where a threshold occurred with a vegetation cover of 36%(P<0.05). The higher total vegetation covers, however, did not result in increased densities of germinated seeds(P>0.05), which on average represented 16.7% of initial seed densities. Even more, three months after the study initiation, total vegetation covers were similar(P>0.05) at all positions in the dunes, and they determined a similar number(P>0.05) of surviving seedlings at those positions(i.e. the second hypothesis had to be rejected). The mean number of seed- lings that survived at all positions was only 4.5% of germinated seeds. The number of surviving elm seedlings(0 to 1.7 seedlings/m2) under various vegetations covers(12.2% to 20.8%) at all dune positions by late summer would most likely not contribute to vegetation restoration in the study area.     

沙地植物幼苗生长对降水和风速变化的响应

为研究沙地植物幼苗生长对降水和风速变化的响应过程,于2016年4月中旬利用40个2m×2m×2m的混凝土样方池,通过人工增雨及遮风网降低风速的方法开展模拟控制实验。结果表明:①风速、降水以及两者的协同作用对萌发物种数无显著影响(P> 0. 05)。风速降低20%和降水增加60%使种子萌发物种数与对照相比分别增加4.9%和1.3%;风速降低20%条件下,自然降水和降水增加60%均可使种子萌发物种数增加7. 2%。②不同降水处理会使植物幼苗密度大幅度降低、高度波动变化;风速降低可以较显著地促进沙地植物幼苗生长高度,特别是优势植物猪毛菜(Salsola collina)、大果虫实(Corispermum macrocarpum)的生长高度(P <0.01)。在自然风速条件下,降水增加30%明显促进猪毛菜幼苗高度生长,降水增加60%则相反;风速降低20%条件下,降水增加60%可以大幅度的促进雾冰黎(Bassia dasyphylla)幼苗的生长高度;风速降低40%与降水增加30%和60%的协同作用使雾冰黎、猪毛菜和大果虫实幼苗的生长高度均明显降低。③不同风速和降水处理对植被的Simpson优势度指数(D)、香浓–威纳多样性指数(H)、Pielou均匀度指数(J)无显著影响(P>0.05)。以上研究结果表明:降水增加30%对种子萌发阶段物种丰富度的抑制作用较大;与降水相比,风速是沙地植物幼苗生长高度的主要影响因素,并且自然降水条件下,风速降低40%可以使沙地植物幼苗生长高度最大限度地增加;沙地植被物种多样性指数对降水及风速的变化不敏感,这说明科尔沁沙地生态系统群落结构相对较为稳定。     

科尔沁沙地青贮玉米蒸散量的估算与分析

为准确估算科尔沁沙地青贮玉米实际蒸散量的变化规律,选用ASCE Penman-Monteith(ASCE-PM)模型计算参考作物蒸散发(ET0);利用双作物系数模型模拟土壤含水率与对应实测值进行统计分析,根据均方根误差、一致性指数、平均绝对误差和Nash-Sutcliffe效率指数4个指标以及回归系数和决定性系数对双作物系数模型进行率定和验证,然后模拟青贮玉米的作物系数,与ASCE-PM模型结合后模拟青贮玉米的蒸散发、棵间土壤蒸发和作物蒸腾规律,并分析其影响因素。结果表明:双作物系数模型准确地模拟土壤含水率和棵间土壤蒸发的变化过程,率定各阶段基础作物系数为0.25、0.9和0.5。棵间土壤蒸发先由播种时峰值下降到较低水平,于收割前有所回升;蒸腾速率除刚出苗和收割前呈单峰变化外大部分时段呈双峰变化,日内变化规律大体为中午高,早晚低,自出苗之日起生长中期后半段处于较高水平,之后逐渐减弱。青贮玉米蒸散量与太阳辐射线性关系最为显著(R=0.643),与气温、空气湿度和风速的相关性依次次之。ASCE-PM模型空气动力项5 d尺度贡献率为27.94%~77.66%,且随风速同增减。综上所述,ASCE-PM模型结合双作物系数可较好估算科尔沁沙地青贮玉米的实际蒸散量,以及棵间土壤蒸发和作物蒸腾量。     

科尔沁城镇化过程对沙地景观的影响

城镇空间扩展所表征的城镇化过程及其对区域景观的影响,是景观生态学研究中的重要方向之一,也是景观生态学中格局-过程研究的重要组成部分。以1985—2013年遥感数据为基础,GIS技术与景观格局分析方法为手段,采用主要指标构建的城镇化指数定量分析了城镇化过程对科尔沁沙地景观的影响。结果表明:近28 a来,区域城镇化发展较快,年均提高0.64%,并呈现阶段性特征,研究区景观变化明显。在斑块水平上,农田、固定沙丘、林地、居工地的面积增加,其余景观类型的面积减少;农田、居工地与林地的破碎化程度增加;农田、固定沙丘最大斑块面积增加最显著,在区域中的优势作用增强。在景观水平上,区域景观破碎化程度减轻,空间集聚程度增加,景观类型组成趋于简单。区域内城镇化过程对不同类型景观的影响存在差异性,其特征表现为城镇化对农田、居工地的影响最大,对其他类型景观的影响较小。城镇化指数与斑块数量、散布与并列指数、香农多样性指数之间存在显著的负相关关系,城镇化指数与蔓延度指数为显著的正相关关系,表现为研究区景观破碎化程度、空间散布程度、异质性均随城镇化水平提高而减小,反映出城镇化与景观变化存在一定的内在联系,选取的景观指数能够反映城镇化过程对区域景观的影响。     

科尔沁沙地不同植物群落土壤呼吸及环境因素分析

对科尔沁沙地固定、半固定和流动沙丘土壤呼吸的日进程、季节变化及其环境因素进行了测定分析.结果表明:1)土壤呼吸速率与植物群落生物量、土壤有机碳、全氮及粘粉粒含量之间存在显著的正相关关系;固定沙丘日平均土壤呼吸速率分别是半固定和流动沙丘的1.18和2.02倍.2)从固定、半固定到流动沙丘,土壤温度及近地表空气温度呈现增加...