Vegetation traits and soil properties in response to utilization patterns of grassland in Hulun Buir City,Inner Mongolia,China

Numerous studies have focused on vegetation traits and soil properties in grassland, few of which concerned about effects of human utilization patterns on grassland yet. Thus, this study hypothesized that human disturbance （e.g., grazing, mowing and fencing） triggered significant variation of biomass partitioning and carbon reallocation. Besides, there existed some differences of species diversity and soil fertility. To address these hypotheses of grassland with diverse utilization patterns in Hulun Buir City, Inner Mongolia, China, we sampled in situ about aboveground biomass （AGB） and belowground biomass （BGB） to evaluate their biomass allocation. Species diversity and soil properties were also investigated. Subsequently, we discussed the relationship of species diversity with environmental conditions, using data collected from 23 sites during the ecological project period of Returning Grazing Lands to Grasslands （RGLG） program. The results were as follows： 1） both AGB and BGB were lower on grazing regime than those on fencing and mowing, but the ratio of root-to-shoot （R/S） was higher on grazing regime than the other two utilization patterns; 2） neither of evenness and Simpson Index was different significantly among all grassland utilization patterns in desert, typical, and meadow grassland at 0.05. In meadow grassland, species richness of fencing pattern was significantly higher than that of grazing pattern （p 〈 0.05）; 3） both of soil organic carbon content and soil available phosphorous content were increased significantly on fencing pattern than grazing pattern （p 〈 0.05） in desert grassland, and mowing patterns increased the soil nutrients （soil organic carbon, soil total phosphorous, soil available phosphorous, and soil total nitrogen） significantly compared with grazing patterns （p 〈 0.05） in typical grassland. However, there were no significant differences among utilization patterns in meadow grassland. In conclusion, both of AGB and BGB were increased s     

中街山水域虾类组成及其群落多样性

根据2010~2011年中街山列岛水域4个季节的渔业资源调查资料,分析了该水域虾类资源密度和群落多样性,并探讨了底层温度、底层盐度和水深对虾类数量分布和多样性的影响.结果表明:共有虾类20种,隶属于9科18属;广温广盐种无论在种类数还是尾数密度与生物量均占主导地位;虾类生物量和尾数密度在季节分布上,以冬季最高,冬季均与春、夏和秋三季呈显著差异(p值<0.05);平面分布上,生物量与密度指数总体上呈南北高、中间低,东部高西部低的特征;生物量与平均底温显著相关(P<0.05),与平均底盐和水深相关性较差(p值>0.05);葛氏长臂虾、细巧仿对虾、中国毛虾、日本鼓虾和中华管鞭虾为四季的优势种,且均属广温广盐种;虾类群落Margalef丰富度指数为0.61~1.09,Shannon-Wiener多样性指数为0.76~1.31,Pielou均匀度指数为0.50~0.70,其中丰富度指数和多样性指数春季与冬季均存在显著差异(P<0.05),均匀度指数秋季与冬季存在显著差异(p值<0.05).     

Higher species diversity occurs in more fertile habitats without fertilizer disturbance in an alpine natural grassland community

Are there some relationships among species diversity and soil chemical properties of high altitude natural grasslands？ Plant community composition and chemical properties of soil samples were compared to investigate the relationship between soil and species diversity, and the richness in Tibetan alpine grasslands. Results showed that species diversity was significantly positively related to soil organic matter （SOM）, total nitrogen （TN）, available nitrogen （AN）, total phosphorus （TP）, available phosphorus （AP）, and available potassium （AK） in the high alpine grasslands. Margalefs species richness index was also significantly positively related to SOM, TN, AN, and TP. Most soil chemical properties showed significantly positive correlation with species diversity and Margalef＇s richness index. Our results suggested that higher plant species richness index and diversity occurred in more fertile soil habitats in high altitude natural grassland community. In practice, fertilization management for the restoration of degraded grassland should be conducted with reference to the nutrient levels ofnatural grassland without the additional artificial fertilizer and with higher species-diversity and richness index.     

Biomass allocation patterns of alpine grassland species and functional groups along a precipitation gradient on the Northern Tibetan Plateau

Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups： forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation （MAP） gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes.     

Differences in tree species diversity and soil nutrient status in a tropical sacred forest ecosystem on Niyamgiri hill range, Eastern Ghats, India

We have quantitatively analyzed the tree species diversity with respect to soil nutrient status in three sites of a sacred forest ecosystem of Niyamgiri hill range,Eastern Ghats,India.Extensive field surveys and sampling were conducted in 3 sites of the hill range:Site 1 Pterocarpus dominated forest(PTF)(19°40’02.2" N and 83°21’23.1" E),Site 2 Mangifera dominated forest(MAF)(19°40’02.8" N and 83°21’40.8" E) and Site 3 Mixed forest(MIF)(19°36’47.1" N and 83°21’02.7" E).A total of 28 families,42 genera,46 tree species,and 286 individual trees were recorded on an area of 0.6 ha.Tree density varied between 470 and 490 individuals ha-1 and average basal area between 3.16 and 10.04 m2 ha-1.Shannon Index(H’) ranged from 2.34 to 4.53,Simpson’s Index ranged from 0.07 to 0.09,and equitability Index ranged from 0.7 to 1.34.The number of individuals was highest in the girth at breast height(GBH) class of 50-70 cm.The soil nutrient status of the three forest types was related to tree species diversity.The soil pH value of the three sites reflected the slightly acidic nature of the area.Species diversity was positively correlated with organic carbon and phosphorus and negatively with nitrogen,EC and pH.The results of the current study may be helpful to further develop a conservation planfor tree species in tropical sacred forest ecosystems.     

Influence of ginseng cultivation under larch plantations on plant diversity and soil properties in Liaoning Province,Northeast China

Currently, transforming the mode of forest management and developing multiple forest management practices are actively encouraged in China. As one forest management type, ginseng cultivation under larch plantations has been developed significantly in the east of Liaoning Province. However, research on the influence of the ecological environment for this mode of production is still deficient. Based on this, our study compares the plant diversity and soil properties in the ginseng cultivation under larch plantations (LG) with larch plantations (LP) and natural secondary forests (SF). First, we randomly selected three plots for each of the three stand types which have similar stand characteristics; then, we carried out a plant diversity survey and soil sampling in each of the nine plots. The results show that no significant difference was found in plant diversity between LG and LP, but the evenness of herbs was significantly lower in LG than LP. No obvious changes in soil physical properties were found in LG, but a significant decrease in most of the soil nutrient content was presented in LG. Furthermore, we found a correlation between plant diversity (H') and soil properties in the three kinds of stand types, especially between herbaceous plant diversity and soil properties. We conclude that ginseng cultivation under larch plantations has no obvious effect on plant diversity, except the herbaceous evenness. Soil fertility can be depleted significantly in LG, but physical structures are not affected. Moreover, maintaining the diversity of herbaceous plants and controlling the density of ginseng cultivation in LG by farmers are important for the ecological environment. Based on this study and its good comprehensive benefits and with the support of policy, we think this forest management type should be promoted moderately in the region.     

Variation in carbon,nitrogen and phosphorus partitioning between above- and belowground biomass along a precipitation gradient at Tibetan Plateau

Precipitation is a potential factor that significantly affects plant nutrient pools by influencing biomass sizes and nutrient concentrations. However, few studies have explicitly dissected carbon(C), nitrogen(N) and phosphorus(P) pools between above- and belowground biomass at the community level along a precipitation gradient. We conducted a transect(approx. 1300 km long) study of Stipa purpurea community in alpine steppe on the Tibet Plateau of China to test the variation of N pool of aboveground biomass/N pool of belowground biomass(AB/BB N) and P pool of aboveground biomass/P pool of belowground biomass(AB/BB P) along a precipitation gradient. The proportion of aboveground biomass decreased significantly from mesic to drier sites. Along the belt transect, the plant N concentration was relatively stable; thus, AB/BB N increased with moisture due to the major influences by above- and belowground biomass allocation. However, P concentration of aboveground biomass decreased significantly with increasing precipitation and AB/BB P did not vary with aridity because of the offset effect of the P concentration and biomass allocation. Precipitation gradients do decouple the N and P pool of a S. purpurea community along a precipitation gradient in alpine steppe. The decreasing of N:P in aboveground biomass in drier regions may indicate much stronger N limitation in more arid area.     

Degradation stage effects on vegetation and soil properties interactions in alpine steppe

In recent decades,overgrazing and the warming and drying climate have resulted in significant degradation of alpine grasslands in the source region of the Yellow River.However,research into the relationships between vegetation and soil properties has mainly focused on an overall degradation stage,and few studies have investigated which soil properties can impact vegetation change at different stages of degradation.Vegetation and soil properties were observed in the field and measured in the laboratory for different predefined stages of degradation for alpine grassland in Maduo County in the source region of the Yellow River.Results show that:1)the aboveground and belowground biomass,soil organic carbon,total nitrogen,nitrate,and ammonia content did not decrease significantly from the intact to moderate degradation stage,but decreased significantly at severe and very severe stages of degradation;2)dominant plant species shifted from gramineaes and sedges to forbs;3)the species richness and Pielou evenness indices decreased significantly at the very severe degradation stage,the Shannon-Wiener diversity index increased at the slight and moderate degradation,but decreased at the severe and very severe degradation stages;4)soil bulk density was the strongest soil driver for changes in the plant biomass and community diversity at the intact,slight and moderate degradation stages,whereas soil organic carbon and nitrate nitrogen content were the main driving factors for changes in plant biomass and diversity at the severe and very severe degradation stages.Our results suggest that there may be different interactions between soil properties and plants before and after moderate stages of degradation.     

Effects of grazing exclusion on plant productivity and soil carbon,nitrogen storage in alpine meadows in northern Tibet,China

Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon （SOC） and soil total nitrogen （STN） storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass （AGB）, belowground biomass （BGB）, SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation （MAP）. Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer （10 cm） after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversitv conservation.     

Soil nutrients in relation to vertical roots distribution in the riparian zone of Three Gorges Reservoir,China

Since the impoundment of the Three Gorges Reservoir (TGR), the riparian zone has been subjected to numerous environmental changes. This study was conducted to recognize the distribution of grass roots and its impacts on soil nutrients in the water level fluctuation zone of TGR. Roots of four predominant herbaceous plants in the study area, specifically, Cynodon dactylon, Hemarthria altissima, Hemarthria compressa, and Paspalum paspaloides, and their corresponding relation with soil nutrient contents were investigated. Root surface area density was determined with WinRHIZO, and the relationships of root distribution with soil depths and soil nutrient contents were studied. The results indicates that most roots are distributed in the top soil layer of 0–10 cm. Estimated root surface area density for the selected grass species ranges from 0.16 to 13.44 cm2/cm3, and decreases exponentially with an increase in soil depth. Soil organic matter and total nitrogen contents are significantly lower on bare control area than the corresponding values on the grasslands. Total nutrient contents on grasslands of C. dactylon and H. compressa are higher than those of other grass areas. Root length density and root surface area density are significantly correlated with soil organic matter and total nitrogen content for the four grasslands. The present results suggests that plant roots have significant effects on the distribution of soil nutrients in soil profiles in the riparian zone along the TGR. Nevertheless, additional investigations are needed to reveal the specific interactions between plant roots distribution, soil nutrients and water level fluctuations.     

虾池浮游微藻的种类组成、数量和多样性变动

报道了在集约化养虾中应用有益微生物制剂对虾池浮游微藻的影响,分析了整个养虾周期浮游微藻的种类组成、生物量、优势种及多样性指数的周期变化情况。结果表明,早期虾池浮游微藻细胞数量维持在1×103~3×103mL-1的水平,养殖中期开始呈指数增长状态,后期达到顶峰,并维持在70×103~160×103mL-1的水平,生物量比自然海区高。优势种类明显,前期为中肋骨条藻和伏氏海毛藻等硅藻类,后期则为绿球藻和栅列藻等绿藻类,水色及藻相呈良好状态,而不施加芽孢杆菌制剂的对照池则在后期出现较大比例的有害的蓝藻。虾池藻类多样性指数、均匀度指数和种类丰度均呈现前期高后期低的趋势,而优势度指数则相反,呈现前期低后期高的趋势。浮游植物的多样性指数为0.60~3.80,平均为1.88,均匀度指数为0.14~0.83,平均为0.45;种类丰度为0.80~2.46,平均为1.38;优势度指数在0.17~0.85,平均为0.41。多样性指数和均匀度均比粤东海域低,但优势度则甚高。     

Responses of Dodonaea viscosa growth and soil biological properties to nitrogen and phosphorus additions in Yuanmou dry-hot valley

Nitrogen(N) and phosphorus(P) are limited nutrients in terrestrial ecosystems, and their limitation patterns are being changed by the increase in N deposition. However, little information concerns the plant growth and the soil biological responses to N and P additions among different soils simultaneously, and these responses may contribute to understand plant-soil interaction and predict plant performance under global change. Thus, this study aimed to explore how N and P limitation changes in different soil types, and reveal the relationship between plant and soil biological responses to nutrient additions. We planted Dodonaea viscosa, a globally distributed species in three soil types(Lixisols, Regosols and Luvisols) in Yuanmou dry-hot valley in Southwest China and fertilized them factorially with N and P. The growth and biomass characters of D. viscosa, soil organic matter, available N, P contents and soil carbon(C), N, P-related enzyme activities were quantified. N addition promoted the growth and leaf N concentration of D. viscosa in Lixisols; N limitation in Lixisols was demonstrated by lower soil available N with higher urease activity. P addition promoted the growth and leaf P concentration of D. viscosa in Luvisols; severe P limitation in Luvisols was demonstrated by a higher soil available N: P ratio with higher phosphatase activity. Urease activity was negatively correlated with soil available N in Nlimited Lixisols, and phosphatase activity was negatively correlated with soil available P in P-limited Luvisols. Besides, the aboveground biomass and leaf N concentration of D. viscosa were positively correlated with soil available N in Lixisols, but the aboveground biomass was negatively correlated with soil available P. Our results show similar nutrient limitation patterns between plant and soil microorganism in the condition of enough C, and the nutrient limitations differ across soil types. With the continued N deposition, N limitation of the Lixisols in dry hot valleys is expected to be alleviated, while P limitation of the Luvisols in the mountaintop may be worse in the future, which should be considered when restoring vegetation.     

Impact of grazing on soil,vegetation and ewe production performances in a semi-arid rangeland

Controlled grazing is considered a good management strategy to maintain or increase the live weight of livestock and to reduce vegetation degradation of rangelands. The present study investigated soil characteristics, aboveground vegetation biomass dynamics and controlled grazinginduced changes in the live weight of local ewes in the semi-arid rangeland of Ahmadun, Ziarat, Balochistan province of Pakistan. An area of 115 ha was protected from livestock grazing in April 2014. In June 2015, soil characteristics within 0-30 cm depth i.e. soil organic matter (SOM), mineral nitrogen, pH and texture in controlled and uncontrolled grazing sites were assessed. Aboveground vegetation biomass measured in early (June) and late summer (August) in 2015 and 2016. The nutritional value i.e. crude protein, phosphorus (P), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca), magnesium (Mg) and potassium (K) of dominant plant species were assessed at the beginning of experiment in 2015. Vegetation cover of controlled and uncontrolled grazing sites was also measured during the two years of the study period using the VegMeasure software. From June to November in 2015 and 2016, controlled and uncontrolled livestock grazing sites were grazed on a daily basis by local ewes with a stocking rate of 2 and 1 head ha-1 respectively. Results reveal that the organic matter contents of coarse-textured, slightly alkaline soil of the study site were in the range of 9.4 - 17.6 g kg-1 soil and showed a strong positive correlation with aboveground vegetation biomass. The biomass of plants was 56.5% and 33% greater at controlled than uncontrolled grazing site in 2015 and 2016 respectively and plant cover was also higher at controlled than uncontrolled grazing site in both years. The nutrient contents were significantly (P<0.05) lower in grasses than shrubs. In both years, the controlled grazing increased the weight gain of ewes about two folds compared to the uncontrolled grazing. The results indicate that controlled grazing improved the vegetation biomass production and small ruminant productivity.     

Soil and vegetation seasonal changes in the grazing Andean Mountain grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna（Vicugna vicugna） and alpaca（Lama pacos）. The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined： total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.     

Changes in SOC and nutrients under intensive tillage in two types of slope landscapes

The net effect of tillage erosion on soil properties would be associated with the spatial variation in soil constituents,and therefore plays an important role in ecological agriculture.We conducted a consecutive tillage by hoeing 15 times during a period with no rainfall in the two slope landscapes(a linear slope and complex slope) of the Yangtze Three Gorges reservoir areas,to examine the relationship between soil erosion rates and the variations in soil chemical properties and compare the effects of soil redistribution on SOC and nutrients between the linear and complex slopes.After the simulated tillage,notable changes in 137 Cs inventories of the soil occurred in the summit and toeslope positions on the linear slope,while there were significant changes in 137 Cs inventories at convex and concave positions on the complex slope.Soil profile disappeared at the summit slope boundary,with the exposure area of 16.0% and 7.6% of the experimental plot,respectively,for the linear and complex slopes due to no soil replacement.Soil organic C and nutrients were completely depleted with the disappearance of soil profiles at soil eroding zones,whereas a remarkable increase in SOC,total N and available nutrient concentrations of the post-tillage surface soil and a decrease in total nutrient concentrations(P and K) were found at depositional zones on the linear slope.For the complex slope,however,changes in SOC and nutrient concentrations of the post-tillage surface soil exhibited a patterndifferent from that on the linear slope,which showed a remarkable decrease in SOC and total nutrient concentrations but a slight increase in available nutrient concentrations after tillage in the toeslope position.Due to the gradual increase in soil depth from top to bottom of the slope,SOC and nutrient inventories in the soil profiles were significantly correlated with soil redistribution rates on both the linear and complex slopes.Tillage causes remarkable changes of soil chemical properties in the surface soil layer and soil profile,and increases SOC and nutrient inventories for the soil profile downslope in steeply sloping landscapes.     

Responses of <Emphasis Type="Italic">Dodonaea viscosa</Emphasis> growth and soil biological properties to nitrogen and phosphorus additions in Yuanmou dry-hot valley

Nitrogen (N) and phosphorus (P) are limited nutrients in terrestrial ecosystems, and their limitation patterns are being changed by the increase in N deposition. However, little information concerns the plant growth and the soil biological responses to N and P additions among different soils simultaneously, and these responses may contribute to understand plant-soil interaction and predict plant performance under global change. Thus, this study aimed to explore how N and P limitation changes in different soil types, and reveal the relationship between plant and soil biological responses to nutrient additions. We planted Dodonaea viscosa, a globally distributed species in three soil types (Lixisols, Regosols and Luvisols) in Yuanmou dry-hot valley in Southwest China and fertilized them factorially with N and P. The growth and biomass characters of D. viscosa, soil organic matter, available N, P contents and soil carbon (C), N, P-related enzyme activities were quantified. N addition promoted the growth and leaf N concentration of D. viscosa in Lixisols; N limitation in Lixisols was demonstrated by lower soil available N with higher urease activity. P addition promoted the growth and leaf P concentration of D. viscosa in Luvisols; severe P limitation in Luvisols was demonstrated by a higher soil available N: P ratio with higher phosphatase activity. Urease activity was negatively correlated with soil available N in Nlimited Lixisols, and phosphatase activity was negatively correlated with soil available P in P-limited Luvisols. Besides, the aboveground biomass and leaf N concentration of D. viscosa were positively correlated with soil available N in Lixisols, but the aboveground biomass was negatively correlated with soil available P. Our results show similar nutrient limitation patterns between plant and soil microorganism in the condition of enough C, and the nutrient limitations differ across soil types. With the continued N deposition, N limitation of the Lixisols in dry hot valleys is expected to be alleviated, while P limitation of the Luvisols in the mountaintop may be worse in the future, which should be considered when restoring vegetation.     

Effect of snow-cover duration on plant species diversity of alpine meadows on the eastern Qinghai-Tibetan Plateau

Although snow cover plays an important role in structuring plant diversity in the alpine zone, there are few studies on the relationship between snow cover and species diversity of alpine meadows on the eastern Qinghai-Tibetan Plateau. To assess the effect of snow cover on plant species diversity of alpine meadows, we used ten parallel transects of 60 m × 1 m for this study and described the changes in species diversity and composition associated with snow depth. With the division of snow depth into six classes, the highest species richness （S） and species diversity （H′） occurred with an intermediate snow depth, i.e., class Ⅲ and class Ⅳ, showing a unimodal curve with the increase in snow depth. The relationship between snow depth and plant diversity （both richness and Shannon index） could be depicted by quadratic equations. There was no evident relationship between diversity （both S and H′） and soil water content, which implied that other more important factors influenced species diversity. The patterns of diversity found in our study were largely attributed to freeze-thaw alteration, length of growing season and disturbances of livestock grazing. Furthermore, snow depth affected species composition, as evaluated by the Sorensen＇s index of similarity. In addition, almost all species limited to one snow depth class were found only in class Ⅲand class Ⅳ, indicating that intermediate snow depth was suitable for the survival and growth of many alpine species.     

Rangeland degradation assessment in Kyrgyzstan: vegetation and soils as indicators of grazing pressure in Naryn Oblast

Rangelands occupy more than 80% of the agricultural land in Kyrgyzstan. At least 30% of Kyrgyz pasture areas are considered to be subject to vegetation and soil degradation. Since animal husbandry is the economic basis to sustain people’s livelihoods, rangeland degradation presents a threat for the majority of the population. We present for the first time an ecological assessment of different pasture types in a remote area of the Naryn Oblast, using vegetation and soils as indicators of rangeland conditions. We analysed the current degree of utilization (grazing pressure), the amount of biomass, soil samples, and vegetation data, using cluster analysis as well as ordination techniques. Winter pastures (kyshtoo) are characterized by higher pH values (average of 7.27) and lower organic matter contents (average of 12.83%) compared to summer pastures (dzailoo) with average pH values of 6.03 and average organic matter contents of 21.05%. Additionally, summer pastures show higher above-ground biomass, and higher species richness and diversity. Our results support the hypothesis that winter pastures, which are located near settlements, suffer from over-utilisation, while the more distant summer pastures are subjected to much lower grazing pressure.     

章丘大葱特征元素农业地球化学研究

以章丘大葱产区生态地球化学调查为基础,采集了表层土壤、大葱、根系土及出露的代表性岩石样品,实测了大量和微量营养元素的含量,查明了研究区土壤地球化学背景。通过计算大葱对土壤营养元素的吸收率及大葱品质与营养元素的相关性分析,查明了大葱生长的特征营养元素为N,K2O,Zn,B,P,Cu,Mn。在岩石-土壤-大葱这一生态体系中,营养元素在土壤中保持一定的储备和积累,为大葱的生长提供了有利的农业地球化学环境。     

Composition,diversity and distribution of tree species in response to changing soil properties with increasing distance from water source – a case study of Gobind Sagar Reservoir in India

Construction of big dams on rivers develops artificial lakes or water reservoirs which conceive alterations in soil properties of the upstream catchment area. An undulating topography and freckly soil properties cause ups and downs in tree diversity, composition and distribution. The study aimed to evaluate the effect of Gobind Sagar reservoir on soil properties relative to the distance from it and assess its effect on tree diversity, evenness and their distribution in tropical and subtropical forests. Based on data analysis it was found that the soil moisture and organic carbon decreased along with increasing distance from the reservoir. It played a significant role in varying tree diversity. The sites distributed within0-2 km showed significantly higher α and β-diversity indices. Tree species richness and diversity indices showed a strong correlation(p 0.05) with soil moisture and organic carbon content. Simpson's and Mc Intosh evenness indices showed a strong negative correlation with soil bulk density. Indirect Detrended Correspondence Analysis(DCA) identified soil moisture and soil organic carbon as two major environmental gradients that influenced tree diversity and their distribution in five tropical and four subtropical forests in an upstream catchment of the reservoir. Mixed forests inhabited moist sites andAcacia-Pinus forests showed an inclination to dry areas. Canonical Correspondence Analysis(CCA)revealed that the tree species in tropical forests were mainly affected by driving forces such as soil moisture,organic carbon and bulk density whereas, in subtropical forest tree species were influenced by elevation, soil p H, EC and clay content.