Formation cause,composition analysis and comprehensive utilization of rare earth solid wastes

Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were comprehensively introduced.Besides,some suggestions on treatment and administration on rare earth solid wastes were put forward.

Short-term Effects of Nitrogen Deposition on Soil Physical and Chemical Properties of Tibetan Forest-Grassland Landscape Boundary

[Objective] The paper was to study the effects of nitrogen deposition on soil nutrients and soil dissolved organic carbon in forest-grass-land landscape in Linzhi, Tibet, and to provide scientific basis and basic data for understanding and assessing the effect of atmospheric nitrogen de-position on soil nutrients and soil dissolved organic carbon. [Method] From July 2014 to August 2015, in situ nitrogen deposition(CK 0 kg·hm^2/a, LN25 kg·hm^2/a, MN 50 kg·hm^2/a, HN 150 kg·hm^2/a) was simulated in the forest-grassland boundary of Zhuqudeng village, Bujiu Township, Linzhi County, Tibet. The soil samples were collected for analyzing nutrient and dissolved contents in the soil layer of 0-20 and 20-40 cm. The effects of different nitrogen deposition levels on soil nutrients and dissolved organic carbon(DOC) were studied. [Result] Nitrogen deposition had significant impacts on soil organic matter, total N, total P, total K, available N, available P, available K, exchangeable Ca, exchangeable Mg, p H, and DOC( P<0.05).(2) With the deepening of nitrogen deposition from CK, LN, MN to HN in the 0-20 cm boundary soil, the contents of organic matter, total N,total P, available P, exchangeable Ca, exchangeable Mg and DOC kept decreasing, and the content of total K and available N increased continuous-ly. The p H increased in LN treatment and decreased in HN treatment, while the available K content was decreased in LN and HN treatment, but increased in MN treatment.(3) The contents of organic matter, total N, total P, available N, available P, exchangeable Ca, exchangeable Mg and DOC all decreased at the soil layer of 20-40 cm under the same nitrogen deposition. The p H increased in LN treatment, but decreased in HN treat-ment; the content of total K decreased in LN treatment and increased in MN and HN treatments; the content of available K decreased in LN and HN treatments, but increased in MN treatment.(4) With the deepening of boundary soil layer(0-20 to 20-40 cm), the organic matter, total N, total P, available P, available K, exchangeable Ca, exchangeable Mg, DOC showed the same response to simulated nitrogen deposition, while the avail-able N and total K responded differently. [Conclusion] Different levels of N deposition had certain impact on soil nutrient, and the variation of soil nutrients was not the same at different levels.

Status and Protection of National Wetland Parks in the Tibet Autonomous Region

This paper summarized the status, the brief history of the construction and development of national wetland parks in the Tibet Autonomous Region, and proposed corresponding measures for their later protection and development, in order to realize the sustainable development of national wetland parks.

Effects of Different Afforestation Techniques on Soil Nutrients in Populus alba Woodland

[Objective] The research aimed to study the influence of different afforestation technology measures on soil nutrients of P. alba woodland in arid valley region of Rikaze,Tibet. It aimed to improve afforestation technology measure in arid valley region of Rikaze,Tibet,and provide theoretic basis for restoring the degraded ecosystem at upper reaches of the Yarlung Zangbo River. [Method] In arid valley region of Duojiao Village,Nanmulin County,Rikaze City,the planted land using rooting powder,egg shell,leaves,mud and water retention agent was taken as research object,while the land without any afforestation measures was taken as the control,to determine soil nutrients under different afforestation measures.[Result]Under different afforestation measures,the contents of various soil nutrients were all obviously higher than control,in which available potassium,available phosphorus,alkali hydrolysable nitrogen and organic matter in soil obviously increased than control,but there was no similar rule among different measures. [Conclusion]Vegetation restoration in dry valley belt of Rikaze by different afforestation measures is favorable for improving physical-chemical properties of soil and increasing soil fertility.

Effect of Acid and Alkali Stress on Seed Germination and Seedling Growth of Caragana versicolor

With seeds of Caragana versicolor in Purang County, Tibet as the materials, the seed germination and seedling growth of C. versicolor were measured under acid and alkali stress, and the soil acidity and alkalinity for normal growth and development of C. versicolor were determined, so as to provide the theoretical basis for cultivation of C. versicolor in acidified or alkaline soil. The results showed that the seed germination of C. versicolor was promoted when treated by strong acid (pH 3) and strong alkali (pH 11) solutions, and the seedling effect was good. The results also indicated that C. versicolor was a kind of plant with strong acid and alkali resistance, suitable for cultivation in acid and alkali soil areas.

Photoresponse Process and Model Comparison of Paeonia ludlowii under Saline-alkali Stress

The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress, and annual seedlings of P. ludlowii were taken as the materials. Photoresponse process of P. ludlowii leaves under saline-alkali stress was simulated, and different models were used to fit photoresponse curve. The results showed that P n of P. ludlowii leaves showed the trend of first rising and then declining with PAR increased under saline-alkali stress;both G s and T r showed a rising trend with PAR increased;C i showed the trend of first declining and then rising with PAR increased. Photoresponse curve fitted by modified rectangular hyperbolic model had the best effect, and it was the optimal fitting model. P. ludlowii could adapt to saline-alkali stress in lower concentration, showing that P. ludlowii could be introduced and cultivated in saline-alkali land at a lower level.

Phenotypic Diversity of Different Populations of Paeonia ludlowii in Nyingchi of Tibet

[Objectives] To study the differences in fruit traits of different populations of Paeonia ludlowii , and to provide basic data for the identification, protection and utilization of germplasm resources of P. ludlowii .[Methods] Nine fruit traits of three different populations of P. ludlowii in Tibet were tested and analyzed.[Results] The mean values of 9 fruit traits of P. ludlowii were different in different populations;the coefficients of variation of different traits of different populations were also different;there were morphological differences of different sizes among individuals in each population;there were significant differences in 8 traits (pod length, pod width, pod thickness, pod weight, seeds per pod, seed length, seed width, and seed weight) among different populations. Among the 9 traits of the three P. ludlowii populations, the variability of the five traits was higher in the fruit pods, the variation degree of five traits including pod weight, pod thickness, seeds per pod, and seed weight was higher. It is of great significance for the screening and preservation of the germplasm resources of P. ludlowii . According to the principal component analysis (PCA), the seed weight, seed width, and seed length, i.e. the seed traits, were the main factors causing differences in fruit traits among populations. There was a certain correlation between different traits of P. ludlowii . Among the 36 Pearson- related combinations of 9 fruit traits, 11 combinations had extremely significant correlations, and 8 combinations had significant correlations, indicating that there was a certain correlation between fruit traits in the growth and development. Through cluster analysis, three populations of P. ludlowii can be divided into two categories. The BV population was a category, which is characterized by long pods, long seeds, wide seeds, thick seeds and large seed weight. Therefore, the BV population is suitable material for breeding excellent varieties.[Conclusions] This study provides basic data for the identification, protection and utilization of germplasm resources of P. ludlowii .

2000-2011年可可西里地区主要湖泊冰情时空变化（英文）

Lake ice phenology,i.e.the timing of freeze-up and break-up and the duration of the ice cover,is regarded as an important indicator of changes in regional climate.Based on the boundary data of lakes,some moderate-high resolution remote sensing datasets including MODIS and Landsat TM/ETM+ images and the meteorological data,the spatial-temporal variations of lake ice phenology in the Hoh Xil region during the period 2000–2011 were analyzed by using RS and GIS technology.And the factors affecting the lake ice phenology were also identified.Some conclusions can be drawn as follows.(1) The time of freeze-up start(FUS) and freeze-up end(FUE) of lake ice appeared in the late October–early November,mid-November – early December,respectively.The duration of lake ice freeze-up was about half a month.The time of break-up start(BUS) and break-up end(BUE) of lake ice were relatively dispersed,and appeared in the early February – early June,early May – early June,respectively.The average ice duration(ID) and the complete ice duration(CID) of lakes were 196 days and 181 days,respectively.(2) The phenology of lake ice in the Hoh Xil region changed dramatically in the last 10 years.Specifically,the FUS and FUE time of lake ice showed an increasingly delaying trend.In contrast,the BUS and BUE time of lake ice presented an advance.This led to the reduction of the ID and CID of lake.The average rates of ID and CID were –2.21 d/a and –1.91 d/a,respectively.(3) The variations of phenology and evolution of lake ice were a result of local and climatic factors.The temperature,lake area,salinity and shape of the shoreline were the main factors affecting the phenology of lake ice.However,the other factors such as the thermal capacity and the geological structure of lake should not be ignored as well.(4) The spatial process of lake ice freeze-up was contrary to its break-up process.The type of lake ice extending from one side of lakeshore to the opposite side was the most in the Hoh Xil region.