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1.
Urban soils, although crucial to defining urban vegetation types and strengthening the resilience of urban ecosystems, can be severely modified by human activities. Yet understanding of these modifications and their implications for soil properties is limited. This study examined the vertical and spatial variability of selected soil physicochemical properties (pH, SOM, OC, TN, and bulk density) in Kumasi, Ghana, using a stratified random sampling technique. Soil samples were collected at three depths (0–15, 15–30, and 30–60 cm) from 161 plots in eight green space types within two urban zones. Mean topsoil pH ranged between 5.0 in the natural forest and 6.5 in home gardens. Mean bulk density, nitrogen, and carbon concentrations differed among green space types and depths (p?<?0.0001). Soil nitrogen and carbon concentrations in the 0–15 cm depth were two times greater than those of the 30–60 cm depth. Soil pH and organic matter concentrations were higher in the core urban soils than in the peri-urban while the reverse was true for total soil N and bulk density. Canonical discriminant analysis showed considerable separation of green space types based on the soil physicochemical properties. Higher total nitrogen and C:N ratios separated natural forest and cemetery from the other UGS types, whereas higher pH and bulk densities separated plantations and home gardens from the rest of the UGS types. Furthermore, the subsoil layers were laden with undecomposed cloths, plastics, concrete, and metal parts which can obstruct root growth and water movement. Results generally demonstrate considerable variability in soil properties among urban green spaces and highlight the need for a better understanding of these patterns to ensure continued support for plant growth, green space sustenance and maintenance, and the ecosystem services derived from them.  相似文献   

2.
Soil moisture variability and controls are little known in large gullies of the Loess Plateau which represent complex topography with steep slopes. This study analyzed spatial–temporal variability of soil moisture at the 0–20, 20–40, 40–60, and 60–80 cm depths in a large gully of the Loess Plateau based on root-zone soil moisture measurements for 3 years (2009–2011). The result showed that mean soil moisture, standard deviation (SD), and coefficient of variation, were highly dependent on depth; the highest mean value was observed at the 20–40 cm depth, while the lowest one was at the 0–20 cm depth. The SD increased with mean soil moisture for various depths as soil moisture was relatively wet; however, a transition that SD decreased with mean soil moisture occurred when soil moisture was relatively dry. Positive correlations exist between moisture contents over different depths, and that the relationships of the neighboring layers are relatively high with R 2 from 0.70 to 0.76. Correlation analysis, principle component analysis, and stepwise multiple regression analysis showed that soil particle size distribution and topography (slope and elevation) were the main environmental factors controlling soil moisture variability in the large gully.  相似文献   

3.
Drastically disturbed soils caused by opencast mining can result in the severe loss of soil structure and increase in soil compactness. To assess the effects of mining activities on reconstructed soils and to track the changes in reclaimed soil properties, the variability of soil properties (soil particle distribution, penetration resistance (PR), pH, and total dissolved salt (TDS)) in the Shanxi Pingshuo Antaibao opencast coal-mine inner dump after dumping and before reclamation was analyzed using a geostatistics method, and the number of soil monitoring points after mined land reclamation was determined. Soil samples were equally collected at 78 sampling sites in the study area with an area of 0.44 km2. Soil particle distribution had moderate variability, except for silt content at the depth of 0–20 cm with a low variability and sand content at the depth of 20–40 cm with a high variability. The pH showed a low variability, and TDS had moderate variability at all depths. The variability of PR was high at the depth of 0–20 cm and moderate at the depth of 20–40 cm. There was no clear trend in the variance with increasing depth for the soil properties. Interpolation using kriging displayed a high heterogeneity of the reconstructed soil properties, and the spatial structure of the original landform was partially or completely destroyed. The root-mean-square error (RMSE) can be used to determine the number of sampling points for soil properties, and 40 is the ideal sampling number for the study site based on cross-validation.  相似文献   

4.
Soil samples from 0 to 100 cm depth were collected in four sampling sites (Sites A, B, C and D) along a 250-m length of sampling zone from the Yellow River channel to a tidal creek in a seasonal flooding wetland of the Yellow River Delta of China in fall of 2007 and spring of 2008 to investigate spatial and seasonal distribution patterns of total phosphorous (TP) and available phosphorus (AP) and their influencing factors. Our results showed that TP contents in spring and AP contents in both seasons in surface soils increased with increasing distances away from the Yellow River channel. TP contents in surface soils (0–10 cm) followed the order Site A (698.6 mg/kg) > Site B (688.0 mg/kg) > Site C (638.8 mg/kg) > Site D (599.2 mg/kg) in fall, while Site C (699.6 mg/kg) > Site D (651.7 mg/kg) > Site B (593.6 mg/kg) > Site A (577.5 mg/kg) in spring. Generally, lower TP content (630.6 mg/kg) and higher AP level (6.2 mg/kg) in surface soils were observed in spring compared to fall (656.2 mg/kg for TP and 5.2 mg/kg for AP). Both TP and AP exhibited similar profile distribution patterns and decreased with depth along soil profiles with one or two accumulation peaks at the depth of 40–80 cm. Although the mean TP content in soil profiles was slightly higher in spring (635.7 mg/kg) than that in fall (628.0 mg/kg), the mean TP stock was obviously lower in spring (959.9 g/m2) with an obvious accumulation at the 60–80 cm soil depth compared to fall (1124.6 g/m2). Topsoil concentration factors also indicated that TP and AP had shallower distribution in soil profiles. Correlation analysis showed that AP had significant and positive correlation with these soil properties such as soil organic matter, salinity, total nitrogen and Al (p < 0.01), but TP was just significantly correlated with TN and Al (p < 0.05).  相似文献   

5.
Karst poljes in the Dinaric Mountains have a complex hydrological regime and high potential for crop production. Little information is available about soil organic carbon (SOC), total nitrogen (TN), carbon stocks (SOCS), and nitrogen stocks (TNS) in karst poljes located in the Dinaric area. The objective of this paper was to study the spatial distribution of SOC and TN in topsoil (ranged from 9 to 53 cm depth) and whole profile SOCS and TNS (ranged from 15 to 160 cm depth) in the Livno karst polje depression (Bosnia and Herzegovina) using kriging and co-kriging approaches. We used the following properties as co-variates: distance from hills (DFH), distance from the lake (DFL), sand, silt, and clay content, TN, SOC, SOCS, and TNS. We only used the properties that had a significant correlation with the estimated properties as co-variates. The results showed that soils in the study area had high average SOC (7.92%), TN (0.79%), SOCS (191.05 t ha?1), and TNS (17.91 t ha?1) values. Histosols had the highest SOCS and TNS and Arenosols the lowest. The experimental variogram of LogSOC and LogTN was best-fitted by the spherical model, while the exponential model was the most accurate for LogSOCS and LogTNS. The spatial dependence was moderate for all studied soil properties. The incorporation of auxiliary variables increased the precision of the estimations from 35.7% (SOC?×?TN) to 49.2% (TNS?×?SOCS).  相似文献   

6.
Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and inconsistent. Our aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0–100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C4) and from natural vegetation (C3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0–10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C4 above 30 cm soil depth increased by 4.5%–5% or 0.11–0.12 g·kg?1 on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation abandonment. The increase in the percentage of C4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment.  相似文献   

7.
Tillage, especially in semiarid Mediterranean environment, enhances the mineralization process of soil organic matter (SOM) and, in turn, decreases aggregate stability. Furthermore, continuous tillage leads to the formation of plough pan beneath the tilled layer. In the present study, we investigated the effect of an innovative self-propelled machine (spading machine, SM) for shallow tillage on SOM, water stable aggregates (WSA) and soil penetration resistance (PR). Such effects were compared to those of chisel plough (CP), rotary tiller (RT) and no tillage (NT). Each tilling method was applied up to a depth of 15 cm, whereas in NT only a brush cutter was used for weed control. Soil analyses were performed at the start of the experiment (March 2009, T0), in April 2010 (T1), May 2012 (T3), and June 2014 (T5) at both 0–15 and 15–30 cm. Compared to T0, soil PR increased with time in all the treatments and generally followed the order SM?<?RT?<?CP?<?NT. In soil tilled with the SM, soil PR never exceeded 2.5 MPa that was demonstrated to be a critical value for root elongation, and no evidence of the formation of plough pan beneath the tilled layer was observed. SOC as well as water content and WSA were higher in SM compared with CP and RT. In conclusion, the spading machine was proved to be more efficient in lowering the soil PR and in avoiding the formation of the plough pan. Furthermore, SM increased SOC and WSA.  相似文献   

8.
Spatial distributions of 0-20 cm soil carbon sources/sinks caused by land use changes from the year 1980 to 2000 in an area of 2.97 × 10~6 km~2 in eastern China were investigated using a land use dataset from a recent soil geochemical survey.A map of soil carbon sources/sinks has been prepared based on a spatial analysis scheme with GIS.Spatial statistics showed that land use changes had caused 30.7 ± 13.64 Tg of surface soil organic carbon loss,which accounts for 0.33%of the total carbon storage of 9.22 Pg.The net effect of the carbon source was estimated to be ~ 71.49 Tg soil carbon decrease and ~40.80 Tg increase.Land use changes in Northeast China(NE) have the largest impact on soil organic carbon storage compared with other regions.Paddy fields,which were mainly transformed into dry farmland in NE,and constructed land in other regions,were the largest carbon sources among the land use types.Swamp land in NE was also another large soil carbon source when it was transformed into dry farmland or paddy fields.Dry farmland in the NE region formed the largest soil organic carbon sink,as some were transformed into paddy fields,forested land,and other land use types with high SOCD.  相似文献   

9.
Phosphorus is an essential and common limiting element for plants. Phosphorus losses from agricultural production systems are known to contribute to accelerated eutrophication of natural waters. In this study, soil available phosphorus (SAP) content and SAP density were estimated based on a soil survey of a small watershed in the Dan River, China, and the spatial heterogeneity of SAP distribution and the impacts of land-use types, elevation, slope and aspect on SAP were assessed. Field sampling was carried out based on a 100 m × 100 m grid system overlaid on the topographic map of the study area, and samples were collected in three soil layers to a depth of 40 cm. A total of 190 sites were sampled, and 539 soil samples were collected. The results showed that classical kriging could successfully interpolate SAP content in the watershed. SAP content showed a downward trend with the increase in soil depth and the extent of SAP variability in the three soil layer is moderate. There were significant differences among the three soil layers (P < 0.01). The land use had a great impact on the SAP content. ANOVA indicated that the spatial variation of SAP contents under different land-use types was significant (P < 0.01). The SAP density of different land-use types followed the order of cropland > forestland > grassland. The mean SAP density of cropland, forestland and grassland at a depth of 0–40 cm was 4.28, 3.74 and 2.81 g/m2, respectively. SAP and topographic factors showed that SAP content increased with decreasing altitude and slope gradient. The soil bulk density played a very important role in the assessment of SAP density. In conclusion, the soils in the source area of the middle Dan River would reduce SAP with conversions from cropland to forest or grassland.  相似文献   

10.
With few available soil organic carbon (SOC) profiles and the heterogeneity of those that do exist, the estimation of SOC pools in karst areas is highly uncertain. Based on the spatial heterogeneity of SOC content of 23,536 samples in a karst watershed, a modified estimation method was determined for SOC storage that exclusively applies to karst areas. The method is a “soil-type method” based on revised calculation indexes for SOC storage. In the present study, the organic carbon contents of different soil types varied greatly, but generally decreased with increasing soil depth. The organic carbon content decreased nearly linearly to a depth of 0–50 cm and then varied at depths of 50–100 cm. Because of the large spatial variability in the karst area, we were able to determine that influences of the different indexes on the estimation of SOC storage decreased as follows: soil thickness > boulder content > rock fragment content > SOC content > bulk density. Using the modified formula, the SOC content in the Houzhai watershed in Puding was estimated to range from 3.53 to 5.44 kg m?2, with an average value of 1.24 kg m?2 to a depth of 20 cm, and from 4.44 to 14.50 kg m?2, with an average value of 12.12 kg m?2 to a depth of 100 cm. The total SOC content was estimated at 5.39 × 105 t.  相似文献   

11.
A study was made to determine the influence of pasture degradation on soil quality indicators that included physical, chemical, biological and micromorphological attributes, along the hillslope positions in Chaharmahal and Bakhtiari province, western Iran. Soil samples from different slope positions were collected from 0 to 30 cm depth for physical and chemical properties and from 0 to 15 cm depth for biological properties at two adjacent sites in the two ecosystems: natural pasture and cultivated land. Soil quality indicators including bulk density, mean weight diameter, soil organic carbon (SOC), particulate organic material (POM) in aggregate fractions, total nitrogen, available potassium, available phosphorus, cation exchange capacity, soil microbial respiration (SMR) and microbial biomass C and N were determined. The results showed that SOC decreased cultivation from 1.09 to 0.77 % following pasture degradation. The POM decreased by about 19.35 % in cultivated soils when compared to natural pasture; also, SMR and microbial biomass C and N decreased significantly following pasture degradation. Furthermore, aggregate stability and pore spaces decreased, and bulk density increased in the cultivated soils. Overall, our results showed that long-term cultivation following pasture degradation led to a decline in soil quality in all selected slope positions at the site studied in the semiarid region.  相似文献   

12.
Preliminary geochemical mapping was carried out within urban areas in Tampere Central Region, Finland, to gain a better understanding of element concentrations in urban soil and to provide information on baselines in soil within urban centres for soil contamination assessment purposes. The soil samples were taken from central city parks, day-care centres and school yards, and residential areas. Various sampling depths have generally been used in urban geochemical surveys. The aim of this study was to compare the results from two commonly used sample types taken from the same sites in urban soil: single samples of minerogenic topsoil from the 0–25 cm layer and composite samples of minerogenic topsoil from a depth of 0–2 cm. The concentrations of most of the studied trace elements showed a significant correlation between samples from 0 to 2 and 0 to 25 cm, but element concentrations differed between the two studied sample depths. For most of the studied elements, the median concentrations were higher in the 0–25 cm samples, but anomalous concentrations were more often found in the 0–2 cm samples. Some elements had elevated concentrations when compared with the Finnish guideline values for soil contamination assessment. This study did not conclusively establish whether a sampling depth of 0–2 or 0–25 cm should be recommended for similar studies in the future. Selection of the sampling depth in geochemical studies greatly depends on the aim of the project. In order to determine the upper limits of geochemical baseline variation, the deeper sampling depth appears to be more feasible. However, for the preliminary health risk assessment of areas with sensitive land uses, e.g. children’s playgrounds, samples from 0–2 cm depth are considered informative. Such samples may also be used to indicate local sources of dusting creating site-specific hotspots of potentially harmful elements in urban topsoil.  相似文献   

13.
This study was carried out to determine the effects of different land-use types on the properties of an Alfisol on the Jos Plateau, Nigeria. Areas being used for nature conservation (forest), grazing and maize cultivation were chosen, and the three are contiguous within a nearly level, moderately well-drained site. Within each of the three land-use areas, a plot of 30 x 20 m was chosen. Each plot was divided into 6 grids of 100 m2 size. Within each of these grids, four sampling sites were chosen by throwing up a coin four times. The four surface soil (0–5 cm depth) samples taken at the points where the coin landed, were mixed to form the composite sample, out of which sizeable portion was taken. This means that six soil samples were taken for each land use area (forest, grass, and cultivated). Same procedure was repeated for each of the following soil depths 5–15, 15–30 and 30–50 cm. Laboratory soil analyses were carried out while analysis of variance was used to test the significance of mean difference. The results show that forest clearing for grazing and maize cultivation has lead to significant decreases in most soil fertility variables. Organic matter levels of the grassland and cultivated soils are just about 28% and 13%, respectively, of that of the forest soil in the 0–5 cm depth, while they are 36% and 19%, respectively, in the 5–15 cm depth. Exchangeable cations and effective cation exchange capacity are also significantly higher in the forest soils. The effects are attributable to soil organic matter decomposition and nutrient removal resulting from forest clearance, maize cultivation and grazing. Hence, for sustained agricultural productivity, the soils require adequate inorganic and organic fertilizer additions together with appropriate cultural practices such as agroforestry, crop rotation and mixed cropping involving legumes.  相似文献   

14.
The concentration and distribution characteristics of toxic elements in soil and plant were investigated in the coal refuse reclaimed areas of Huainan, China. Ninety soil samples from different depth (0–20, 20–40, 40–60 cm) and 120 plant samples were collected based on grid sampling method. The concentrations of the selected toxic elements (As, Cd, Cu, Ni, Pb and Zn) in the soil and plant samples were determined by using inductively coupled plasma mass spectrometry. The elevated concentrations of toxic elements in the soils at the depth of 20–40 and 40–60 cm suggested that the coal refuse reclamation may lead to potential environmental impacts. The toxic element tolerance could be observed in all the selected plant samples. The concentrations of toxic elements in the underground tissues were higher than that of aboveground tissues. Conclusively, the present study provided a comprehensive evaluation of soil and plant toxic element implications from coal refuse reclaimed areas in China and was also helpful for environmental protection and monitoring the safety of plant.  相似文献   

15.
Soil crust and slope angle are of important factors affecting runoff production and sediment yield. In the hilly areas of the Loess Plateau, North China, slope lands are distributed extensively and subjected to soil crusting; therefore, the research on the responses of runoff and soil loss to soil crust and slope angle is essential to soil and water conservation. In the study, five pairs of 1 m × 5 m plots with slope angles of 5°, 10°, 15°, 20° and 25° respectively, were established in Wangjiagou watershed, which was located at the Loess Plateau, China. Based on the two simulated rainfall events, uncrusted surface prior to the first simulated rainfall event, and crusted surface prior to the second rainfall event were distinguished. The runoff production and soil loss were measured at intervals of 5 min during the simulated events. It indicated that both soil crust and slope angle played an important role in runoff production and soil loss. With the reference slope angle of 5°, the relative importance of soil crust and slope angle in runoff production was calculated. It showed that soil crust effect on the total runoff volume decreased from 100 to ～40%, while slope angle effect increased from 0 to ～60% with increasing slope angle because soil crust less developed on the steeper slopes. Furthermore, soil crust effect was associated with rainfall duration. At the same slope angle, the relative importance of soil crust decreased with rainfall duration because new crust was formed on the uncrusted surface. The critical slope of erosion was also discussed. Soil loss increased with slope angle when the slope angle was less than 20°. Generally speaking, soil crust effect decreased with slope angle and/or rainfall duration.  相似文献   

16.
Haloxylon ammodendron Bge (C.A. Mey.) is a dominant shrub species in the Gurbantonggut Desert and plays an important role in preventing wind erosion and combating desertification, typically by developing fertile islands in desert ecosystems; however, such islands often depend on the scales. An experiment was conducted to determine the scale dependence for the soil spatial heterogeneity of H. ammodendron in the Gurbantonggut Desert using the soil pH, electrical conductivity (EC), soil organic carbon (SOC), and total nitrogen (TN). The results showed that the soil EC, SOC and TN were significantly higher at the individual scale than the population scale. Moreover, the coefficients of variation (CV %) of the soil parameters at the individual scale were greater than they were at the population scale, with all except for pH (CV = 4.35 % for individual scale and CV = 2.87 % for population scale) presenting a moderate degree of variability (10 % < CV < 100 %). A geostatistical analysis revealed a strong spatial dependence [C 0 /(C 0 + C) < 25 %] within the distance of ranges for the tested parameters at both scales. The kriging interpolation results presented significant accumulation of soil SOC and TN around the shrub center and formed a significant “fertile island” at the individual scale, whereas the soil EC was much lower at the shrub center. At the population scale, patch fragments of the soil chemical properties were observed; however, not all individuals presented significant fertile islands or salt islands, and the soil EC presented a similar distribution as SOC and TN. These differences suggested that different mechanisms controlled the spatial distribution of soil minerals at the two scales and that the spatial heterogeneities are scale-dependent in a desert ecosystem.  相似文献   

17.
The potential mineralization and immobilization of soil nitrogen (N), phosphorus (P) and sulfur (S) are relatively high in natural ecosystems. This study was conducted to investigate the changes in essential plant macronutrients; N, P, and S status in response to different soil depth in rangeland ecosystems in vitro. The net nutrient mineralization was measured during 90 days at different depths (0–15, 15–30, 30–45 and 45–60 cm), using kinetic models to estimate the release rate. The net ammonification and mineralization of P and S were described using parabolic diffusion equation, while the power function equation was used to describe the net nitrification. The results indicated that the amount of released ammonium (NH4 +) decreased with time and depth and the rates of net ammonification were negative in all samples. Conversely, nitrification increased with time and depth and the rates were all positive. The net mineralization for both P and S reduced with time. The concentration of mineralized SO4 2? increased with depth like nitrate (NO3 ?). Accumulation of SO4 2? and NO3 ? in subsurface soils and NH4 + and P at surface horizons can increase the potential of their loss by leaching or volatilization.  相似文献   

18.
Information on soil water storage (SWS) within soil profiles is essential in order to characterize hydrological and biological processes. One of the challenges is to develop low cost and efficient sampling strategies for area estimation of profile SWS. To test the existence of certain sample locations which consistently represent mean behavior irrespective of soil profile wetness, temporal stability of SWS in ten soil layers from 0 to 400 cm was analyzed in two land uses (grassland and shrub land), on the Chinese Loess Plateau. Temporal stability analyses were conducted using two methods viz. Spearman rank correlation coefficient (r s) and mean relative differences. The results showed that both spatial variability and time stability of SWS increased with increasing soil depth, and this trend was mainly observed at above 200 cm depth. High r s (p?<?0.01) indicated a strong temporal stability of spatial patterns for all soil layers. Temporal stability increased with increasing soil depth, based on either r s or standard deviation of relative difference index. The boundary between the temporal unstable and stable layer of SWS for shrub land and grassland uses was 280 and 160 cm depth, respectively. No single location could represent the mean SWS for all ten soil layers. For temporal stable layers, however, some sampling locations could represent the mean SWS at different layers. With increasing soil depth, more locations were able to estimate the mean SWS of the area, and the accuracy of prediction for the representative locations also increased.  相似文献   

19.
The present study examines the spatial dependency of soil organic matter and nutrients in paddy fields at three different scales using geostatistics and geographic information system techniques (GIS). The spatial variability of soil organic matter (SOM), total nitrogen (TN) and available phosphorus (AP) has been characterized using a total of 460, 131 and 64 samples that were, respectively, collected from the Hangzhou–Jiaxing–Huzhou (HJH) Plain (10 km), Pinghu county (1,000 m) and a test plot area (100 m) within the Pinghu county, Zhejiang province of the southeast China. Semivariograms showed that the SOM and TN had moderate spatial dependency on the large scale of HJH plain and moderate scale of Pinghu county with long spatial correlation distances. At the moderate scale of Pinghu county and the small scale of a test plot area, the AP data did not show any spatial correlation, but had moderate spatial dependency in HJH plain. Spherical and exponential variogram models were best fitted to all these soil properties. Maps of SOM and TN were generated through interpolation of measured values by ordinary kriging, and AP by lognormal kriging. This study suggests that precision management of SOM and TN is feasible at all scales, and precision management of AP is feasible at large scales.  相似文献   

20.
The objective of this study was to examine the variation of time and space and the effects of alpine meadow desertification, and the study area was selected at the Qinghai–Tibet Plateau of China. The sampling locations were categorized as the top, middle, bottom of the slope and flat in front of the slope, and the sites were classified as alpine meadow, light desertified land, moderate desertified land, serious desertified land, and very serious desertified land according to the level of alpine meadow desertification. This study examined spatial and temporal variability in soil organic carbon (SOC), total nitrogen (TN), pH, and soil bulk density due to wind erosion and documents the relationship between soil properties and desertification of alpine meadows. Desertification caused decreases to soil organic carbon and total nitrogen and increases to pH and soil bulk density. Soil properties were greatly affected by the level of alpine meadow desertification with the changes being attributed to overgrazing. The middle portion of slopes was identified as being the most susceptible to desertification. Carbon and nitrogen stocks were found to decrease as desertification progressed, the SOC stocks were 274.70, 273.81, 285.26, 196.20, and 144.36 g m?2 in the alpine meadow, light desertified land, moderate desertified land, serious desertified land and very serious desertified land, respectively; and the TN stocks were 27.23, 27.11, 28.35, 20.97, and 17.09 g m?2 at the top 30 cm soil layer, respectively. To alleviate desertification of alpine meadow, conservative grazing practices should be implemented.  相似文献   

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