灌木植物量测定技术的研究   总被引：13，自引：0，他引：13  

刘存琦 《草业学报》1994,3(4):61-65

本文对梭梭，柠条，毛条和花棒四种树冠具有代表性的旱生灌木植物量的测定技术进行了系统的分析和研究，结果表明：用传统的样方收获法测定这类灌木的植物量不具备实际的可行性，而数量化处理法，相对生长法和标准木法是测定这类植被植物量的理想方法，其中以数量化处理法效果最佳，相对生长法次之。  相似文献   

小叶锦鸡儿灌丛化对退化沙质草地土壤孔隙特征的影响   总被引：3，自引：0，他引：3  

李宗超  胡霞 《土壤学报》2015,52(1):242-248

以内蒙古太卜寺旗地区退化沙质草地为研究对象,对该地区的小叶锦鸡儿灌丛化草地中的灌丛斑块和草地斑块分别取原状土柱各三个进行CT扫描,利用Fiji软件分析土壤孔隙结构特征的差异。研究结果表明,小叶锦鸡儿灌丛化对土壤的孔隙结构有较大影响,灌丛斑块土壤的总孔隙数、大孔隙数、总孔隙度、大孔隙度和孔隙等效直径均大于草地斑块土壤,灌丛斑块土壤的平均大孔隙度是草地斑块土壤的3倍。草地斑块土壤的大孔隙主要分布在0~50 mm土层深度,而灌丛斑块土壤的大孔隙在0~400 mm深度都有分布,这与土壤中灌丛的丰富根系分布有关。  相似文献   

Storage of biomass and net primary productivity in desert shrubland of Artemisia ordosica on Ordos Plateau of Inner Mongolia, China     

Jin Zhao  Qi Yu-chun  Dong Yun-she 《林业研究》2007,18(4):298-300

Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.  相似文献   

Characterizing rangeland vegetation using Landsat and 1-mm VLSA data in central Wyoming (USA)     

Ramesh Sivanpillai  D. Terrance Booth 《Agroforestry Systems》2008,73(1):55-64

As an alternative to ground-cover data collection by conventional and expensive sampling techniques, we compared measurements obtained from very large scale aerial (VLSA) imagery for calibrating moderate resolution Landsat data. Using a grid-based sampling scheme, 162 VLSA images were acquired at 100 m above ground level. The percent vegetation cover in each photo was derived using SamplePoint (a manual inventory method) and VegMeasure (a reflectance based, automated method). Approximately two-thirds of the VLSA images were used for calibrating Landsat data while the remainder was used for validation. Regression models with Landsat bands accounted for 55% of the VegMeasure-based measurements of vegetation, whereas models that included both Landsat bands and elevation data accounted for 67%. The relationship between the Landsat bands and the percent vegetation cover measured by SamplePoint was lower (R ² = 20%), highlighting the differences between the inventory and reflectance based protocols. Results from the model validation indicated that the model’s predictive power was lower when the vegetation cover was either <20% or >55%. Additional work is needed in these ecosystems to improve the calibration techniques for sites with low and high vegetation cover; however, these results demonstrate the VLSA imagery could be used for calibrating Landsat data and deriving rangeland vegetation cover. By adopting such methodologies the US Federal land management agencies can increase the efficiency of the monitoring programs in Wyoming and in other western states of the US. Mention of trade names is for information only and does not imply endorsement by USDA over comparable products or services.  相似文献   

白羊草灌丛草地种群生态位的研究   总被引：2，自引：0，他引：2  

许庆方董宽虎  魏来翠张瑞红柴娅红  杜新平韩河平 《四川草原》2006,(2):1-5

运用以Shannon-Wieren指数为基础的生态位宽度计测公式和Pianka的生态位重叠计测公式,在土壤水分、土壤pH值、土壤全氮含量3个资源维上研究白羊草灌丛草地主要植物种群生态位宽度和生态位重叠关系。建群种白羊草的平均生态位最高,为0．905;达乌里胡枝子的生态位宽度仅次于白羊草。表明白羊草、达乌里胡枝子具有最强的耐受北方寒冷干燥及家畜放牧利用的能力。白羊草在3个资源维上同其他种群的生态住重叠值都较高,表明其在群落中具有较强的占据资源优势能力。因此,在对退化白羊草灌丛草地植被恢复时,白羊草和达乌里胡枝子是首选草种。  相似文献   

Estimation of above-ground biomass and carbon stock of an invasive woody shrub in the subtropical deciduous forests of Doon Valley,western Himalaya,India   总被引：1，自引：0，他引：1  

Gautam Mandal  S.P.Joshi 《林业研究》2015,26(2)

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盐胁迫对2个灌木柳无性系光响应特征的影响     

隋德宗  王保松  王伟伟 《江苏林业科技》2014,41(5):10-13

以2个灌木柳无性系(盐敏感型JW9-6和耐盐型JW2372)为试验材料,在温室水培条件下研究不同质量浓度盐(0,3,6 g/L)处理3 d对其光响应特征的影响。结果表明:2个无性系的最大净光合速率、饱和光强、表观量子效率和气孔导度均随盐质量浓度的升高而逐渐降低;根据气孔导度随光照度变化趋势的研究结果,认为6 g/L盐质量浓度处理引起JW2372和JW9-6光合速率下降的原因分别是气孔因素和非气孔因素;相同盐质量浓度处理条件下JW2372光响应特征参数受影响比JW9-6小,对光照强的利用能力更高。  相似文献   

基于TDT原理的灌木水分传感器探头设计与实验   总被引：1，自引：0，他引：1  

王海兰  张新  盛文溢  赵燕东 《农业机械学报》2014,45(5):259-264

根据时域传输TDT法,设计了灌木茎体含水率测量装置。装置由高频信号源、同轴传输线、缠绕式探头及相位比较电路4部分组成。高频电磁波在不同介质中的传播速度不同,表现为在不同介质中的传播相位不同,而含水灌木介电常数的大小主要取决于其含水率的大小,因此通过测量电磁波在同轴电缆上A和缠绕于灌木茎体上探头B的相位差来获取灌木的含水率。选择吸水棉棒来模拟不同含水率的灌木,研究高频信号源工作频率、探头结构对相位差的影响。实验表明,当探针长度为60 cm,信号源频率为50 MHz和100 MHz时,A、B两路电磁波信号的相位差与棉棒吸水率变化呈单调性,且具有良好的相关性。  相似文献   

盐池沙地主要饲料灌木树种特性的观测   总被引：3，自引：0，他引：3  

李生宝  王北  白永强  王力 《林业科学》2000,36(4):119-125

为了更好地提高灌木饲料林的经营管理水平,提高其利用率,在过去研究的基础上(李生宝等,1993,王　北等,1992),对饲料灌木树种的特性进行了研究。1　研究地区自然及社会经济概况研究地位于北纬37°47′～38°40′,东径106°42′～107°45′,为宁夏盐池县北部毛乌素沙地西南边缘。干旱少雨,风多沙大,光热资源丰富,年均气温77℃,1月平均气温-89℃,7月平均气温223℃,年温差312℃,≥10℃的积温29449℃,年日照时数28679ｈ,无霜期145ｄ,年降水量250～300ｍｍ,且主要集中在7、8、9几个月,约占全年降水量的60%以上,年变率大于30%,蒸发量是降水量的72倍…  相似文献   

Moderate sheep grazing in semiarid shrubland alters small-scale soil surface structure and patch properties     

Carly Golodets  Bertrand Boeken   《CATENA》2006,65(3):351

We investigated whether long-term moderate livestock grazing by sheep (ca. 10 animal unit days/ha) in a semiarid shrubland with a long-term average annual rainfall of 200 mm causes changes in soil surface structure and dimensions of shrub and intershrub patches. We examined grazing-induced changes in landscape patchiness, patch structure, and soil moisture in three grazed and three ungrazed plots of 4 m × 4 m on a south-facing slope and the opposite, more productive north-facing slope. The measurements were done in early spring 2001 and 2002 before grazing started, in two surveys, one using two parallel transects and one using sample quadrats of 20 cm × 30 cm under three shrubs per plot and on an adjacent part of the intershrub matrix. On the north-facing slope, the sheep reduced shrub patch size as they trampled the soil mounds under the shrubs and browsed the shrub canopy. Reduced shrub patch size decreases the area and resources available for plant production. On the south-facing slope, the sheep mainly disrupted the soil crust in the intershrub area. This may increase soil erosion, but also seedling establishment. The contrast in impacts on the two slopes is due to the interaction between environment (productivity, exposure and vegetation) and sheep behavior (herbivory and trampling). On both slopes, the changes due to grazing are significant, though small. Changes in patch size and properties induced by moderate grazing can have positive and negative effects on productivity and diversity, but may also be viewed as early signs of landscape degradation as is often caused by heavy grazing.  相似文献