乌兰布和沙区的水资源条件与治理开发的节水措施

分析乌兰布和沙区的水资源现状和开发潜力，探讨沙区黄灌区和井灌区的节水措施，提出防止土壤盐渍化是沙区治理开发过程中应十分注意的问题。     

Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land, Northwest China

Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen (δ²H) and oxygen (δ¹⁸O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species (Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content (SWC), the soil water profile of the three species stands was divided into active (0.01 g g^-1 < SWC < 0.08 g g^-1, 20% < coefficient of variation (CV) < 45%), stable (0.02 g g^-1 < SWC < 0.05 g g^-1, CV < 20%), and moist (0.08 g g^-1 < SWC < 0.20 g g^-1, CV > 45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep (59.2% ±9.7%, moist layer and groundwater), intermediate (57.4% ±9.8%, stable and moist layers), and shallow (54.4% ±10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early (June) dry season; then, they switched to the active and stable layers in the rainy season (July–September) for water resources (50.1%–62.5%). In the late (October–November) dry season, P. sylvestris (54.5%–66.2%) and A. pedunculata (52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila (52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant phenology, root distribution, and water demand are the main factors affecting the seasonal water-use patterns of artificial sand-fixing plants. Our study addresses the issue of plant water uptake with knowledge of proportional source-water use and reveals important implications for future vegetation restoration and water management in the Mu Us sandy land and similar desert regions around the world.     

科尔沁沙地耐旱乡土灌木树种的选择及其生长比较

在干旱年份，从科尔沁沙地干燥沙丘选择特别耐旱的灌木树种进行育苗试验。通过对1、2年生苗木生长状况分析：叶底珠（Securinega suffruticosa）、鼠李（Rhamnus porflorus）、桃叶卫矛（Evonyms bungeanus）、驼绒蒿（Eurotia arborescens）和杠柳（Periplocasepium）等适应性强，1年生苗木高度为对照树种胡枝子的49．6％～101．8％，2年生苗木为对照树种胡枝子的89．0％～97．9％，可以进一步进行沙地造林试验；东北木蓼生长缓慢，不宜继续进行造林试验。     

内蒙古杭锦旗穿沙公路沿线水资源合理开发利用

内蒙古杭锦旗“穿沙公路”,穿越库布齐沙漠 ,沿线防沙治沙工程及生态工程的建设 ,均与水资源的合理开发利用有密切关系。本文根据已有资料和野外调查结果 ,对公路沿线水资源的基本特征进行了分析 ,提出了水资源合理开发利用的措施和建议 ,可为实践工作所参考。     

Population Studies of Limonium stocksii (Plumbaginacea) from a Salt Desert Near the Arabian Sea Coast

Abstract

A population of Limonium stocksii was studied for one year at the upper end of Manora Creek along the Arabian Sea coast, near Karachi, Pakistan. The community was divided into three zones. Soil pH varied from 8.1 to 8.5. Soil conductivity was highest (191 dS m^?1) in September and lowest (55 dS m^?1) in June. Soil water content was relatively low and varied from 1.6% in February to 9.5% in June. Limonium stocksii maintained a persistent seed bank, which peaked at 5,887 seeds m^?2 in May. Very slow growth was observed; however, plants in the intermediate zone showed better growth than the other two zones. Stem and leaf tissue water content were affected by salinity fluctuations, but root tissue water remained unaffected. Sodium (Na⁺) and chloride (Cl^?) accumulated in stems and leaves more than other ions. Leaves also accumulated a very high amount of magnesium (Mg⁺⁺) compared to roots and stems.     

荒漠草原植被覆盖对土壤水分的影响

以希拉穆仁草原为研究对象,通过对不同植被覆盖下土壤水分进行测定,研究了荒漠草原植被覆盖对土壤水分的影响,结果表明:植被覆盖度与土壤水分之间具有显著的相关关系,尤其是10 cm深度范围内土壤水分随植被盖度呈二次抛物线性趋势增加(R2=0.904 9);由于根系层分布的差异使得土壤剖面不同深度上对这种影响的水分响应不尽相同,灌丛植被覆盖的土壤水分含量在剖面0～40cm范围内明显大于其他植被类型,以坡顶土壤含水量最低;荒漠草原植被覆盖状况变化不仅影响土壤水分含量大小,而且显著影响土壤水分的空间分布,退化较轻的河滩草甸植被有利于维持相对均匀的土壤水分空间分布.     

Community structure and carbon and nitrogen storage of sagebrush desert under grazing exclusion in Northwest China

Overgrazing is regarded as one of the key factors of vegetation and soil degradation in the arid and semi-arid regions of Northwest China.Grazing exclusion(GE)is one of the most common pathways used to restore degraded grasslands and to improve their ecosystem services.Nevertheless,there are still significant controversies concerning GE’s effects on grassland diversity as well as carbon(C)and nitrogen(N)storage.It remains poorly understood in the arid desert regions,whilst being essential for the sustainable use of grassland resources.To assess the effects of GE on community characteristics and C and N storage of desert plant community in the arid desert regions,we investigated the community structure and plant biomass,as well as C and N storage of plants and soil(0-100 cm depth)in short-term GE(three years)plots and adjacent long-term freely grazing(FG)plots in the areas of sagebrush desert in Northwest China,which are important both for spring-autumn seasonal pasture and for ecological conservation.Our findings indicated that GE was beneficial to the average height,coverage and aboveground biomass(including stems,leaves and inflorescences,and litter)of desert plant community,to the species richness and importance values of subshrubs and perennial herbs,and to the biomass C and N storage of aboveground parts(P<0.05).However,GE was not beneficial to the importance values of annual herbs,root/shoot ratio and total N concentration in the 0-5 and 5-10 cm soil layers(P<0.05).Additionally,the plant density,belowground biomass,and soil organic C concentration and C storage in the 0-100 cm soil layer could not be significantly changed by short-term GE(three years).The results suggest that,although GE was not beneficial for C sequestration in the sagebrush desert ecosystem,it is an effective strategy for improving productivity,diversity,and C and N storage of plants.As a result,GE can be used to rehabilitate degraded grasslands in the arid desert regions of Northwest China.     

榆林沙漠休闲旅游开发初探

沙漠是一种特殊的旅游资源，沙漠旅游正成为一种新兴的旅游方式。积极开发榆林沙漠旅游资源，有利于全面推进榆林旅游经济的可持续发展。本文在分析榆林沙漠旅游资源现状的基础上，对榆林沙漠休闲旅游的可持续发展思路与对策进行了初步探讨。     

古尔班通古特沙漠南缘脊椎动物群落的摄食集团及其生态适应

本文依据实地观测资料，探讨了古尔班通古特沙漠南缘区脊椎动物群落各摄食集团的动种构成及其随物候期食物资料变化所产生的相应分化和转换，揭示出该区域脊椎动物食集团具有不稳定的特征，分析得出，少数生态适应性强的物种摄食量集团的分化是维系沙质荒漠生态系统完整性的重要生态过程，它介研究脊椎动物群落营养结构动态的关键摄食集团。