云南西洋参产区生态物候分析

滇西北的丽江县1984年开始从美国引进西洋参试种,1987年取得初步成功,并通过省级鉴定。1988年栽种面积扩大到2000平方米。在推广种植过程叶中,因生产者栽培管理经验不足,完全参照外地的资料和经验,对西洋参生长期间遮萌、土壤水份调节不当,使光照偏大、参棚漏雨、土壤潮湿。

疏叶骆驼刺〔Alhagi sparsifolia(B.Keller et Shap.)Shap.〕的物候学分析

对吐鲁番沙漠植物园中自然分布的疏叶骆驼刺〔Alhagisparsifolia (B .KelleretShap .)Shap .〕的物候进行了 5a连续的观测 ,编绘了物候图谱。运用主成分分析方法 ,对影响疏叶骆驼刺物候的温度和光照因子进行了分析 ,揭示出与其主要物候期关系最为密切的气象因子 ,表明不同的物候期 ,诱导物候表现的主导因子不同 :诱导疏叶骆驼刺萌动期的主要气象因子为旬均最高温、旬均最低温和累计日照时数 ;诱导开花期的主要气象因子为≥ 5℃积温、花期平均日照长度和盛期旬均温 ;诱导果熟期最主要的环境因子有始熟旬均温、累积日照时数和全熟旬均温。

应用乡土树种的物候学及生理学解析——以沈阳城市绿化树种为例

树木是城市植被最主要的组成部分,树种选择是城市绿化是否成功的关键,直接影响到城市生态建设的可持续发展。文中通过对沈阳市城市绿化外来树种和乡土树种物候期及生长情况的调查,结合国内外树木物候学和生理学研究进展,揭示城市绿化应用乡土树种的物候学和生理学原理,以期对我国的城市绿化树种选择起到借鉴和指导作用。

基于植被光学厚度的全球植被动态监测进展

植被光学厚度(vegetation optical depth,VOD)为一种基于微波的植被含水量和生物量估算方法。与光学遥感相比,卫星VOD对大气扰动的敏感性较低,可测量植被不同方面的特征和信息,为全球植被监测提供了一个独立和互补的数据源,已经被广泛用于研究全球气候和环境变化对植被的影响。了解目前VOD在全球植被动态监测的应用研究进展,对其进一步发展和深入应用非常重要。鉴于此,文章首先重点介绍了被动微波和主动微波反演VOD的主要方法,对比分析不同传感器VOD产品的主要特点;然后,从植被特征监测(如植被含水量、生物量)、碳平衡分析、干旱监测、物候分析等方面总结当前VOD在植被动态监测应用方面的研究进展;最后,探讨了VOD产品的优缺点和改进方法,进一步展望了VOD技术在植被动态监测中的应用前景。

Study on Phenological Character in Seedling Period of Introduced Populus deltoids Clones

In order to provide directionally genetically improved breeding materials of poplar by exploring the phenological traits genetic variation level and its develop- ment potential of Populus deltoides and the resource evaluation was carried out; 8 phenological phases in seedling period were observed and analyzed of 60 Populus deltoids clones introduced from America. The results showed that： （1） there was obvious difference in phonological character among clones, especially in leaf-spread- ing peak stage and the end term of leaf-falling stage, with the largest variation co- efficient of 14.97% and the minimum of 3.83% respectively. （2） Leaf-spreading peak stage scattered but the end term of leaf-falling stage concentrated the most. The phonological character in early stage of seedling growth was the main factor influ- encing the length of growing season. （3） By principal component analysis, pheno- logical phases were classified into 3 typical periods, including germination stage, leaf-spreading peak stage and leaf-falling stage. （4） Totaling 60 clones were classi- fied into 4 types by using clustering analysis in phenological time variables of clones.

Paleoclimate Study of Mountain Ecosystems by Multiple Group Biological Analysis

Methodological problems of climatic reconstruction for different periods of Holocene are discussed on the basis of a multiple group biological analysis on peat-sapropel sediments. The possibility of biological analysis is exemplified by the paleoclimatic reconstruction for Carpathian and Altai Mountain ranges. For the ＂Skolevsky Beskidy＂ national park of Carpaty the paleoclimatic scenarios have been drown up aiming at the more precise definition of climatic conditions for the period of mass mountain slope terracing. The stability of terrace systems of various designs in the current climatic conditions has been assessed. It is shown that during periods of humid climate the terraces, whose designs have been focused on drainage, were built. In periods of dry and warm climate the terrace systems capable of accumulating water were built. Both these types of terrace systems are destroyed in nowadays. Only those terrace systems are stable which were adjusted by their builders to contrast variations of precipitation. For Western Altais the paleoclimatic scenario has been done to forecast the safety of the Bronze Age kurgans （burial earth mounds） with permafrost inside the construction. In the Altay region during the Holocene it has revealed two periods of sharp cooling, the peaks of which occurred in the intervals 4500- 4300 and 2500-2300 years pronounced climatic drying ago, and two periods of 4900-4700 and 130-70 years ago. Depletion of the algae composition in the layer corresponding to the last period of drying climate indicates a very sharp change in the parameters of moisture and turning the lake into a dry swamp. Periods of cold weather may have contributed to the formation of special ritual traditions of the Sakan tribes that require the frozen ground to bury the dead. The later climate fluctuations identified have not affected the safety of permafrost in burial mounds constructed in the V-III cc BC.

The Role of Harmattan in the Edaphic Processes in the Extreme-North-Cameroon

In the Cameroonian sudano-sahelian and sahelian zone, karal soils i.e., vertisoils and soils with vertic similarities largely spread on tropical black clay in depressions and fiat sectors. Those black cotton soils are out of season＇s sorghum loft, locally called as muskwari. As the staple diet in the Cameroonian dry areas, this crop becomes more and more an alternative to drying or better to climate changes. Till now, those soils are considered to be lacustrine or they are resulting just from weathering, according to pedologic researchs. The purpose of this communication, therefore, is to show the effects of Harmattan on the basis of our field＇s observations, investigations and superficial deposits＇ analysis： granulometry and diffractometry in the laboratory. Harmattan is a dry and stable air mass which originates from the saharian anticyclone. Its participation in edaphics process is very relevant. Indeed, dust storms take place throughout the dry season and vertisoil spreads out on various topographic locations bringing about homogeneity of texture and similarity of mineralogic spectrum. Their high kaolinite content, thin granulometric component （fine sand, silt and clay） are indicative of Aeolian loessial dust deposits. It could not be something else in this area of the most southern saharian blow of the great Saharo-Sahelian GWAS （global wind action system） in sub-equatorial latitudes, in line with the venturi formed by Ennedi and Tibesti mountains.

Spatio-temporal Characteristics of the Extreme Climate Events and Their Potential Effects on Crop Yield in Ethiopia

Extreme climate events exhibit an increasing spatio-temporal trend globally, and the increasing intensity and frequency may have severe impacts on the human society and natural ecosystems. This study analyzed the extreme temperature and precipitation variability from 1956 to 2016, and evaluated their potential effects on crop yield in Ethiopia. Relative extreme temperature indices exhibited a decreasing trend with low-temperature events, but a significantly upward trend with extreme high temperature events. The frequency of annual warm nights increased to a greater degree than that of cold days. The total annual wet-day precipitation decreased significantly at a rate of-46 mm/decade. Further, the succession of dry days gradually increased by 5.6 day/decade, while an opposite trend of wet days was found with a decline of 1.4 day/decade. The correlation between annual precipitation and crop production was 0.422, indicating that extreme precipitation indices may have higher explanatory power than extreme temperature indices in the crop yield variations. Moreover, the extreme climate changes have induced significant adverse impacts on crops yield particularly in Ethiopia where no proper adaptation measures have been implemented.