我国变革时期道德“沙化”现象之思考

2 0世纪八九十年代我国社会变革时期出现的道德严重“沙化”现象 ,是对五六十年代社会道德的辩证否定。它并不意味着我国社会道德的整体颓废与堕落 ,相反 ,这一客观现实背后却孕育着中国社会和中国人对道德建设的强烈愿望和要求 。

大学写作生态的“沙化”现象研究

当前大学写作教学日益成为受教者的包袱,也成为施教者的教学障碍,形成了"学生厌写,教师烦改"双向停滞局面,结果是教师以讲为主,写作理论有规可循,但最终双方倍感困惑;学生以学写作理论为主,无有效写作操作与写作训练,更无写作的最终规律,于是师生双方茫然失措,致使整个大学不同阶段写作教学恶性循环。教与学双方名副其实陷入"沙化"现象。本文试就目前大学写作教学中存在的现象,剖析并研究写作教育中的"沙化"现象。

阅读教学“沙化”现象的思考

在目前的阅读教学中，不少同志急功近利，他们一头扎进应试教学的大海，在阅读教材中刻意搜寻“知识点”，在阅读教学中憋足劲儿训练“能力点”，结果呢，阅读教材被肢解得“千疮百孔”，而阅读教学自然显得支离破碎。教学内容琐杂不能指向阅读理解，教学思路细碎缺少整体...

论人文生态“沙化”的原因与对策

自然生态被破坏会有什么后果 ,1 998年中国的洪水泛滥和近年持续不断出现的沙尘暴天气 ,已给人们上了很生动的一课 ;而人文生态“沙化”会有些什么 ?人们似乎还缺乏一种清醒的估价。

Seasonal Changes in Photosynthetic Characteristics of Ammopiptanthus mongolicus

Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.

Variations in tidal currents and suspended sediment concentration of the upper part of the North Channel of Changjiang Estuary over the past 10 years

The tidal current duration （TCD） and velocity （TCV） and suspended sediment concentration （SSC） were measured in the dry season in December, 2011 and in the flood season in June, 2012 at the upper part of the North Channel of Changjiang Estuary. They were assimilated with the measured data in 2003, 2004, 2006 and 2007, using the tidal range＇s proportion conversion. Variations in TCD and TCV, preferential flow and SSC have been calculated. Influences of typical engineering projects such as Qingcaosha fresh water reservoir, Yangtze River Bridge, and land reclamation on the ebb and flood TCD, TCV and SSC in the North Channel for the last 10 years are discussed. The results show that： （1） currently, in the upper part of North Channel, the ebb tide dominates; after the construction of the typical projects, ebb TCD and TCV tends to be larger and the vertical average ebb and flood SSC decrease during the flood season while SSC increases during the dry season; （2） changes in the vertical average TCV are mainly contributed by seasonal runoff variation during the flood season, which is larger in the flood season than that in the dry season; the controlling parameters of increasing ebb TCD and TCV are those large-scale engineering projects in the North Channel; variation in SSC may result mainly from the reduction of basin annual sediment loads, large-scale nearshore projects and so on.

Effects of peat and weathered coal on the growth of Pinus sylvestrisvar. mongolica seedlings on aeolian sandy soil

The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.

Effects of Vegetation Restoration in Different Types on Soil Nutrients in Southern Edge of Mu Us Sandy Land

In order to explore effects of vegetation on nutrients in soils, nutrients characters of soils under natural grass, closed grass, abandoned lands, forest lands returned from farmlands and fixed sandy areas in Mu Us Desert were researched. The results indicated that vegetations in varied types have different effects on organic matter, total N, available N and available P, among which the first three were all higher in soils under closed grass, forest lands returned from farmlands, and fixed sandy lands than those under natural grass and abandoned lands. This was totally contrary with contents of available P in soil. In addition, nutrients in soils at 0-20 cm were more influenced by vegetation, than those at 20-60 cm, and Caragana Korshinskii proved better in improving nutrients in soils.

Relation of Wind-induced Sand Displacement to Plant Biomass and Plant Sand-binding Capacity

Desertification is a process in which vegetation cover degrades followed by increased wind and water erosion. Plants adapted to moving sand conditions are able to reverse this process. They can stabilize die substrate. Not much data is available on the soil stabilization capacity of plants. This study was conducted to investigate the wind-induced sand displacement around plants in relation to their biomass. Sand displacement is examined in relation to the biomass allocation pattern of three different plant species. A new method was developed to experimentally investigate plant sand-binding capacity. The relationship between sand displacement and plant biomass was not linear. Apart from the amount of biomass, species-specific plant characters like the biomass allocation pattern and plant structure may be very important in determining the sand-binding capacity.

Effects of Artificial Vegetation Restoration on Soil Physicochemical Properties in Southern Edge of Mu Us Sandy Land

[Objective] This study aimed to investigate the artificial vegetations on soil physicochemical properties of sandy land. [Method] The soil physicochemical proper- ties in five representative lands respectively covered by Artemisia ordosica, Salix cheilophila, Hedysarum scoparium, Populus simonii and Amorpha fruticosa, all of which were planted artificially at the same year were measured in the present study, using a bare soil as the control. [Result] Artificial vegetation improved the soil physicochemical properties by different extents in the lands covered by different plants. The soil physicochemical properties such as bulk density under A. Fruticosa and H. Scoparium were improved greatly. The frequency distribution of soil particle size under artificial vegetations exhibited a bimodal curve. The average soil particle size under A. fruticosa was the smallest, and the soil was very poorly sorted. The soil nutrients in the sandy land were not significantly improved by artificial vegeta- tion. [Conclusion] Artificial vegetation has a certain impact on soil properties in sandy land, as it greatly improves the soil physical properties but not the chemical properties.

Informational digital diagrams applied to predict spring wind,snow,and sandstorms

Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi＇an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.

土壤侵蚀及其治理途径

自然界的雨水落到地面,一部分渗透到土壤深层,一部分过剩的雨水则形成地表迳流,夹带泥沙,流入附近的江河、湖泊或海洋,这一自然过程,就是人们通常所说的“水土流失”作用。 水土流失是土壤遭受侵蚀的结果。由于土壤侵蚀所造成的农业土地资源的破坏,使整个农业生态系统失去平衡,给农业生产带来了非常不利的影响,因此防治土壤侵蚀已成为国内外农业工作者面临的一项紧迫而又带战略性的任务。

Study on the Water Balance in Three Dominant Plants with Simulated Precipitation Change in Maowusu Sandland

The distribution pattern and productivity of Maowusu sandland terrestrial ecosystem are greatly affected with the future severe global change, especially global precipitation change. Considering the predicative global precipitation change and the appropriate relevant strategy for the sustainable development of the China dry territory, the authors have investigated the response of water balance to global precipitation change by creating an artificial control of four levels of water supply treating 3 dominant plants in Mauwusu sandland. The results showed that the seasonal changes of water storage and moisture of different sandland layer depths were affected by different water supply treatments and different plants. The water storage of the three plant growing sandlands and the moisture of different sandland layer depths increased as water supply was increased. The moisture of different water supply treatments and plants increased with the increase of sandland layer depth. The water storage and moisture of the same layer depth of Hedysarum mongolicum Turcz. growing sandland were larger than that of Salix psammophila C. Wang et Ch. Y. Yang growing sandland, which were in turn higher than that of Artemisia ordosica Krasch. growing sandland in the same water supply treatment. Water supply significantly affected the seasonal changes of evaporation and transpiration of the three plant growing sandlands. With the increased levels of water supply, viz. 157.5 mm, 315.0 mm, 472.5 mm and 630.0 mm, the total evaporation was 123.66 mm, 258.68 mm, 376.30 mm, 458.57 mm, respectively, and the total transpiration of A. ordosica was 50.80 mm, 68.93 mm, 108.39 mm, 163.36 mm, respectively, and that of S. psammophila , 47.37 mm, 68.17 mm, 93.65 mm, 135.97 mm, respectively, and that of H. mongolicum 46.73 mm, 67.37 mm, 86.07 mm, 109.64 mm, respectively. Evaporation was significantly higher than transpiration in the experiment.

DYNAMICS OF SANDY DESERTIFICATION AND ITS DRIVING FORCES IN WESTERN JILIN PROVINCE

By establishing the interpreting elements, and applying supervised classification, the sandy desertific- ation was interpreted and the desertified land areas of the counties in the western Jilin Province in 1986 and in 2000 were obtained. Taking Tongyu and Qian’an as examples, the natural driving forces and man-made driving forces were analyzed. The paper comes the conclusions that the material sources and the warming and dry climate are the internal causes of potential land desertification; the irrational human activities, such as destroying forest and reclaiming the grassland, are the external causes of potential land desertification; while more rational human activities, such as planting trees and restoring grassland can reverse the land desertification. Furthermore, the countermeasures and suggestions for the development of agriculture and animal husbandry in the western Jilin Province are put forward.

Integrated controlling technique of ecological environment in Shendong Mining Area

To enclose the interactive relation between the underground mining with suitable protection for surface ecological environments and surface prevention of ecological environments adapting to mining disturbing was researched and developed core of this technique. There are three aspects of controlling ecological environments, to dispose and renew before exploitation, to protect surface ecological environments in the exploitative process and to repair and build up after exploitation. Based on the moving law of overburden strata in shallow seam, the surface subsidence law and the growth law of vegetation in subsidence mine area, the integrated controlling technique has been developed synthetically by methods of theoretic analysis, laboratory simulation, numerical calculation, commercial test etc.. It includes the key techniques of aquifer-protective mining, filtering and purging of mine water through goaf, preventing and extinguishing fire in shallow seam no-rock roadway layout and waste disposal in underground, frame-building ecological functional sphere before exploitation, frame-building the ecological cycle using system after mining and so on.

IMPROVEMENT OF SANDY SOIL WITH WATER-CONSERVING MEMBRANE AND ITS EFFECT ON CROP GROWTH

Water-conserving membrane is a new material of improving sandy soil. It is based on the rule that a compound with organic and inorganic components can produce colloid after its integrating with Ca2+ in soil. The water-conserving membrane will obstruct capillary and increase viscidity of sandy soil, so as to decrease leakage and evaporation in sandy soil. The water-conserving membrane contains polyacrylic acid (PAA) and bentonite. When PAA concentration and pH of solution are different, water-conserving membrane can be made in different depth of soil. This experiment shows that the solution with 0.2% PAA does not harm and poison the crops, on the contrary, promotes crop germination. The solution with 0.2% or 0.4% PAA can accelerate corn growth. Accordingly, different crops need the application of the different PAA concentrations in the cultivation. Therefore, on the basis of different vadose coefficient in sandy soil, the solution with different PAA concentration can improve sandy soil and increase its water-conserving competence very well. The solution can be used to improve sandy soil and control desert enlargement in arid, semi-arid and semi-humid areas.

Analysis and assessment of land desertification in Xinjiang based on RS and GIS

The land desertification in Xinjiang was monitored and analyzed based on RS and GIS techniques. Satellite data interpretation was adopted to obtain the general situation of Xinjiang’s land desertification in assistance with the sampling method and on-the-spot investigations. Related monitoring and investigations showed that Xinjiang was facing with severe wide range land desertification, and its desertified area made up 77.08% of the total monitoring area. As for land types, the desertified farmland accounted for 1.92% of the total monitoring area, desertified woodland 4%, desertified grassland 45%, and unused land 49%. Accordingly, as for desertification degrees, non-desertified land occupied 22.92%, weak desertified land 5.69%, medium-degree desertified land 16.58%, severe desertified land 33.19% and super severe desertified land 21.61%. Finally, as for inducing factors, wind-eroded desertification made up 58.23%, water-eroded desertification 8.69%, salinization desertification 6.52% and frozen-melt eroded desertification 3.64%. Xinjiang’s land desertification tended to get worse and the harnessing mission remained hard.