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Purpose: Grasslands are an important ecosystem covering about a quarter of the earth's surface. Different management practices of grassland ecosystems can have a major impact on the sustainability of these ecosystems. The objective of this study was to determine the impact of different pasture management practices on soil properties and microbial communities in the semi-arid grassland ecosystem in Inner Mongolia. Materials and methods: Long-term experimental plots were established in the semi-arid grasslands of Inner Mongolia to study the effect of different grazing practices on soil properties and microbial communities. The treatments included (1) enclosure from grazing since 1983 (E83), (2) enclosure from grazing since 1996 (E96), and (3) continuous free grazing (FG). We collected the soil samples from these treatments to study soil properties and microbial biomass abundance and diversity. An incubation study was also conducted using soils from E96 and FG treatments to determine the growth responses of ammonia oxidizers to urea addition. Results and discussion: Soil organic matter and total N increased when the grassland was enclosed from grazing, but soil fertility did not increase further with continued enclosure extending from 1996 to 1983. Enclosure also increased microbial biomass but did not significantly affect the microbial diversity. Both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) grew when supplied with urea-N, but the growth rate was higher in the soil from FG than in the soils from enclosed areas. The phospholipid fatty acids (PLFAs) of bacteria i15:0, 16:1 ω7c, 16:1 ω5c, 16:0, 18:1 ω7c, and actinomycetes 10-Me-16:0 used the most of the C-urea in both the E83 and FG soils. There was higher incorporation of C in PLFA 16:0 in the E83 soil after 3 and 7 days incubation, compared with the FG soil, suggesting higher metabolic activity in the E83 soil than the soil from the FG treatment. Most of the effects by the different pasture management practices were confined to the surface soil (0-20 cm), and there was minimal effect in the subsoils (below 20 cm). Conclusions: These results suggest that enclosure of grassland from grazing not only affects soil fertility but also microbial biomass and ammonia-oxidizing populations. Microbial communities are sensitive to pasture management changes, and these have implications to nutrient cycling and management in these grassland ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: In order to identify the areas in the Xilingele grassland which are sensitive to wind erosion, a computational fluid dynamics model (CFD-WEM) was used to simulate the wind fields over a region of 37km2 which contains different topography and land use types. Previous studies revealed the important influences of topography and land use on wind erosion in the Xilingele grassland. Topography influences wind fields at large scale, and land use influences wind fields near the ground. Two steps were designed to implement the CFD wind simulation, and they were respectively to simulate the influence of topography and surface roughness on the wind. Digital elevation model (DEM) and surface roughness length were the key inputs for the CFD simulation. The wind simulation by CFD-WEM was validated by a wind data set which was measured simultaneously at six positions in the field. Three scenarios with different wind velocities were designed based on observed dust storm events, and wind fields were simulated according to these scenarios to predict the sensitive areas to wind erosion. General assumptions that cropland is the most sensitive area to wind erosion and heavily and moderately grazed grasslands are both sensitive etc. can be refined by the modelling of CFD-WEM. Aided by the results of this study, the land use planning and protection measures against wind erosion can be more efficient. Based on the case study in the Xilingele grassland, a method of regional wind erosion assessment aided by CFD wind simulation is summarized. The essence of this method is a combination of CFD wind simulation and determination of threshold wind velocity for wind erosion. Because of the physically-based simulation and the flexibility of the method, it can be generalised to other regions. [Copyright &y& Elsevier]

Aims: The aims of this study were to identify areas of wind erosion and dust deposition and to quantify the effects of different grazing intensities on soil redistribution rates in grasslands based on the Cs technique. Because the method uses a reference inventory as threshold for erosion or deposition, the classification of any other site as source or sink for dust depends on the accurate selection of this reference site. Methods: Measurements of Cs inventories and depth distributions were carried out at pasture sites with predominant species of Stipa grandis and Leymus chinensis which are grazed with different intensities. Additional measurements were made at arable land, plant-covered sand dunes and alluvial plains. Wind-induced soil erosion and dust deposition rates were calculated from Cs inventories by means of the 'Profile-Distribution' and the 'Mass Balance II' models. Results: The selection of the reference site was based on fluid dynamical and process-determining parameters. The chosen site should meet the following four conditions: (i) located at a summit position with obviously low deposition rates, (ii) sufficient vegetation cover to prevent wind erosion, (iii) plane to exclude water erosion and (iv) in the wind/dust shadow of a higher elevation. The measured reference inventory of Cs was 1967(±102) Bqm located at a summit position of moderately grazed Leymus chinensis steppe. The Cs inventories at other sites ranged from 1330 Bqm at heavily grazed sites to 5119 Bqm at river deposits, representing annual average soil losses of up to 130 tkm and deposits of up to 540 tkm, respectively. The calculated annual averages of dust depositions at ungrazed Leymus chinensis sites were related to the dust storm frequencies of the last 50 years resulting in a description of the temporal variability of annual dust depositions from about 154 tkm in the 1960s to 26 tkm at recent times. Based on this quantification already 80% of the total dust depositions can be related to the 20 years between the 1960s and the end of the 1970s and only 20% to the time between 1980 and 2001. Conclusions: Cs technique is a promising method to assess the effect of grazing intensity and land use types on the spatial variability of wind-induced soil and dust redistribution processes in semi-arid grasslands. However, considerable efforts are needed to identify a reliable reference site, because erosion and deposition induced by wind may occur at the same places. The combination of the dust deposition rates derived from Cs profile data with the dust storm frequencies is helpful for a better reconstruction of the temporal variability of dust deposition and wind erosion in this region. The calculated recent deposition rates of about 20 tkm are in good agreement with data of other authors. [ABSTRACT FROM AUTHOR]

The objective of this study was to detect the fluoride level in the drinking water and the urine of habitants aged 16–55 years living in Inner Mongolia China. Furthermore, fluoride concentration of the brick tea infusion samples which were drunk by Mongolia herdsmen in everyday life living in SumuErga village of Ejin Horo Banner, Inner Mongolia China was also determined. A total of 117 participants (61 female and 56 male) were recruited from two counties for a cross-sectional study on health effects of chronic fluoride exposure from drinking water and drinking brick tea infusion. The fluoride concentration in drinking water, urine and brick tea infusion samples were determined using fluoride ion selective electrode method obtained from the Ministry of Health of the People''s Republic of China. The average fluoride concentration in drinking water samples was 0.32±0.01mg/L at AretengXire town of Ejin Horo Banner, 0.70±0.19mg/L at SumuErga village of Ejin Horo Banner, and 2.68±1.15mg/L at ZhalaiNuoer district of Manzhouli city. The average fluoride concentration in brick tea infusion samples which collected from Mongolia herdsmen at SumuErga village of Ejin Horo Banner was 1.81±1.09mg/L. The average urinary fluoride concentration at AretengXire town of Ejin Horo Banner was 0.59±0.48mg/L, at SumuErga village of Ejin Horo Banner was 1.45±0.93mg/L and at ZhalaiNuoer district of Manzhouli city was 3.06±1.53mg/L. The higher fluoride levels in the urine of participants may be associated to higher fluoride in drinking water at ZhalaiNuoer of Manzhouli city. However, drinking brick tea infusions with higher fluoride may be the cause of the higher fluoride contents in the Mongolia herdsmen''s urine. [Copyright &y& Elsevier]

Abstract: A diverse fossil conifer wood assemblage was described from the Late Paleozoic Angaran deposits in Inner Mongolia (=Nei Mongol) of northeastern China. The fossil wood materials were collected from the Upper Carboniferous Baoligemiao Formation in Sunitezuo Qi and the Middle Permian Zhesi Formation in Xi Ujimgin Qi, northeastern Inner Mongolia, including four species. Among them, Sinopalaeospiroxylon baoligemiaoense gen. et sp. nov. represents a new taxon of secondary xylem with Araucarioid-type and transitional type of radial wall pitting, and tertiary taxoid spiral thickenings. It is characterized by the pinioid pitting and nodular thickening on the end wall on the horizontal wall of rays. Sclerospiroxylon neimongolense sp. nov. is represented by a xylem cylinder containing the secondary and primary xylem and pith. The tracheids on the radial wall yield Araucarioid-type pitting as well as a taxoid tertiary spiral thickening. The primary xylem is of endarch, and the pith consists of heterogenous cells. The sclerochyma cells are scattered among the parenchymatous tissues. Zalesskioxylon zhesiense sp. nov. is a wood species with very similar anatomical features to those of the genus Araucarioxylon. It differs, however, in having simple and no-bordered cross-filed pitting in Z. zhesiense. Chapmanoxylon xiugiense (Zhang and Zheng) comb. nov. is recognized based upon wood xylems containing Araucarioxylon-type secondary xylem, endarch primary xylem and a pith yielding homogenous parenchyma cells. These conifer wood taxa show more or less growth rings in the secondary xylem. Such fossil woods from the Late Paleozoic deposits of northeastern Inner Mongolia imply a warm moderate vegetation type. It is a composition part of the Northern Biogeographic Realm in China showing seasonal variation of the palaeoclimate. [Copyright &y& Elsevier]

Renin is a rate-limiting enzyme of the renin-angiotensin system and plays a crucial role in the regulation of blood pressure (BP). Angiotensinogen (AGT) is the precursor of potent vasoactive hormone angiotensin II and the AGT gene has been incriminated as a marker for genetic predisposition to essential hypertension (EH) in some ethnic groups. The purpose of the study is to explore the association of a new genetic marker of renin gene, and AGT gene M235T, A-6G, and A-20C polymorphisms and their haplotypes with EH in the Mongolian population. On the basis of the prevalence survey, 243 hypertensives and 258 normotensives who had no blood relationship with each other were selected as subjects. All the subjects were interviewed with questionnaires and their blood specimens were collected. Renin gene insertion/ deletion (I/D) polymorphism was genotyped by PCR-polyacrylamide gel electrophoresis. AGT gene M235T, A-6G, and A-20C polymorphisms were genotyped by a PCR-restriction fragment length polymorphism and single-strand conformation polymorphism. The frequencies of renin genotype DD and allele D in hypertensives (36.21%, 63.79%, respectively) were significantly higher than those in normotensives (29.84%, 57.17%, respectively, P < 0.05). The odds ratios (OR) of renin genotype ID, DD to renin genotype II on hypertension were 1.98 (OR 95% CI 1.08-3.72) and 2.51 (OR 95% CI 1.33-4.88), respectively. There were no significant differences in the distributions of genotypes and alleles for AGT gene M235T, A-6G, and A-20C polymorphisms and all different haplotypes between the two groups. Renin gene I/D polymorphism is associated with EH, whereas AGT gene M235T, A-6G, and A-20C polymorphisms and the haplotypes are not associated with EH in the Mongolian population.

Objective: To investigate the association of specific functional gene ACE (I/D) variants of the renin-angiotensin system with essential hypertension (EH) and interaction between ACE (I/D) gene and risk factors for EH in a genetically homogenous Mongolia rural population of China., Methods: Individuals (n=1099) were recruited from general population of Kezuohouqi Banner in Inner Mongolian Autonomous Region., Results: The association was found between ACE genotype DD plus ID and EH, with an interaction between ACE genotype DD plus ID and cigarette smoking in an additive model. Cigarette smoking index and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 7.10 to 1.16. Interaction between ACE genotype DD plus ID and alcohol drinking on EH appeared an additive model. Alcohol drinking index and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 1.66 to 1.09. BMI and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 6.15 to 2.49. Interactions between ACE genotype and WHR on EH showed a multiplicative model. In a short,there was an interaction between ACE gene and cigarette smoking, alcohol drinking and BMI on EH, especially in a low dose-exposure effect, Conclusion: It is important for individuals who carry ACE D allele gene to prevent EH, and furthermore, to prevent and control coronary heart disease, in a view of population-based prevention.