Artemisia Gmelinii Research Articles

To Investigate the Impact of Land Use Change on the Potential Groundwater Recharge on Hillslope With Deep Loess Deposits

ABSTRACTAccurately estimating groundwater recharge in hilly areas with limited water and thick vadose zones is challenging. This study investigated the impact of land use changes on groundwater recharge at a hillslope scale of Yuanzegou Watershed in China's Loess Plateau. Three adjacent hillslopes were selected for three different land uses: arbor (jujube, Ziziphus jujuba Mill.), subshrub (native grass, Artemisia gmelinii), and crop (millet, Setaria italica). Soil cores (as deep as 10–16/18 m) were collected at each of the three landscape positions on a hillslope. Reported tritium profiles in the watershed were used to estimate the net chloride input into vadose zone on hillslope associated with inverse chloride mass balance (CMB) method/chloride accumulation method (CAM). Soil water content and chloride profiles in the study were measured to determine recharge rates at each landscape position beneath different vegetation types. For the first time, we evaluated the actual chloride input into vadose zone on hillslopes as 540.2 ± 23.8 mg m−2 yr.−1, excluding the impact of runoff. Then, estimated recharge rates ranged from 42.7 ± 3.5 to 62.4 ± 4.7 mm yr.−1, consistent with nearby studies. Results showed that groundwater recharge does not change with landscape position except for higher value on upslope beneath subshrub hillslope. In contrast, groundwater recharge did significantly reduce by 12.9% ± 5.4% and 26.5% ± 4.5% after conversion from cropland to subshrub/arbor on the hillslope, respectively. Our findings contribute to understanding the ecohydrological effects of land use changes on groundwater recharge on hillslope and help to select suitable afforested vegetation for greening efforts in water‐limited hilly areas, with a priority on groundwater safety.

The Combined Effect of Taproot and Fibrous Roots of Herbaceous Plants and Shrubs on the Distribution of Soil Water-Stable Aggregates

Soil aggregation, an important indicator of soil restoration in degraded ecosystems, is a fundamental unit of soil structure. However, research on the influence of grass–shrub composites on the distribution of >0.25 mm soil water-stable aggregates (macroaggregates) is scarce. Therefore, this study focuses on the hill and gully region of the Loess Plateau, where vegetation has been well restored since the return of farmland to forests and grasslands. The study investigated the root and macroaggregate distribution characteristics and interrelationships of three widely distributed mixed vegetation types of Caragana korshinskii and Agropyron cristatum (C-AC), C. korshinskii and Bothriochloa ischaemum (C-BI), and C. korshinskii and Artemisia gmelinii (C-AG) in this area. The results indicate that soil macroaggregates decrease with increasing depth. Due to the spatial differences in the distribution of shrub root, the content of macroaggregates at 50 cm from the shrub base was higher than that at the shrub base, with an increase of 25.98%–34.27% in different vegetation associations. In this study, the root length density and root diameter better reflected the influence of roots on the distribution of macroaggregates, and the product of the two had a good power function relationship with the content of macroaggregates (R2 ≥ 0.82, p < 0.01). Grey correlation analysis showed that the influence of root length density on the distribution of large aggregates was greater than that of root diameter. The content of macroaggregates in the vegetation association of taproot herbaceous plants and shrubs was higher than that of fibrous root herbaceous plants. The average soil macroaggregate content in the C-AG was 15.79%–248.6% higher than that in the C-BI and C-AC. In this study, the spatial distribution differences in root caused by shrub growth were the main reason for the spatial heterogeneity of soil macroaggregate content distribution. The improvement ability of soil macroaggregates was higher in the combination of taproot herbaceous plants and shrubs than in the combination of fibrous root herbaceous plants and shrubs. The results of this study can, to some extent, reveal the influence and mechanisms of plant roots on soil aggregates in grass–shrub vegetation association.

Биотопическое распределение пауков-кругопрядов (Aranei: Araneidae) острова Аскольд (залив Петра Великого, Приморье)

The article presents the data on the species composition, abundance, spatial and biotopical distribution of orb-weaver spiders on Askold Island, located in Russia's Far East, in the Peter the Great Gulf (Primorsky Krai). The material was collected from 21 key sites of 3 x 25 m, by entomological sweeping and manually. A total of 507 spiders, belonging to 13 species from 8 genera, were captured. Of these, one species - Singa hamate - is indicated for the first time. On the island the most widespread spiders are of the genus Araneus, living in 11 out of 13 types of biotopes. For this genus, the most favorable are forest habitats, dominated by A. ishisawai and A. ventricosus. In open meadow biotopes, 8 species of spiders from 6 genera were recorded, with Neoscona adianta dominating: reaching the density of 29 specimens per 100 m2 in open plant communities with predominance of Artemisia gmelinii. In various parts of the island within linden and broad-leaved multi-species forests, the greatest diversity and abundance of orb-weaver spiders is recorded. There spiders from 3 genera (5 species of each) were caught. Their total density is 42.5 specimens per 100 m2. Stony beaches, stretching along the entire coast of the island, are characterized by the poorest faunal composition. One species encountered was Araneus ventricosus (4 specimens per 100 m2). For the Askold Island, a series of schematic distribution maps for the common species of orb-weaver spiders (A. ishisawai, A. ventricosus, A. macacus, Argiope bruennichi, Neoscona adianta, Plebs sachalinensis) has been compiled for the first time.

Distinct variations of soil infiltrability of contrasting root types in a temperate mosaic-pattern grassland in northern China

Soil infiltration capacity is an important factor affecting soil moisture, and is of great significance to plant growth and groundwater recharge in arid and semiarid areas. Patchiness of grasslands widely exist and have a crucial effect on hydrological processes in water-limited regions. This study investigated soil infiltrability under natural grasslands with patchy mosaic patterns based on a series of in-situ tests. Two dominated natural restoration vegetation communities (Bothriochloa ischaemum (B. ischaemum) with fibrous root systems and Artemisia gmelinii (A. gmelinii) with tap root systems) and abandoned land (as control) were selected in the loess hilly and gully region of the Loess Plateau, China. The results showed that natural restoration grasslands significantly improved soil infiltrability in both plant and bare patches, and the emergence of patchy mosaic patterns can result in infiltration heterogeneity to redistribute water on a hillslope scale. Compared to B. ischaemum, A. gmelinii are more likely to facilitate the formation of preferential flow, contributing to the increased soil infiltration rates. The initial, steady and average infiltration rates (IIR, SIR, and AIR, respectively) and soil infiltration capacity index (SIC) were all negatively correlated with both root length density (RLD) and root surface area density (RSAD) of fine roots (diameter < 2 mm) but positively correlated with those of coarse roots (diameter ≥ 2 mm). The main factors influencing the infiltration capacity were the mean weight diameter in the 10−20 cm layer and the RSAD of the fine roots in the 0−20 cm layer, which can explain 98.6 %, 81.7 %, 63.9 %, and 91.3 % of the total variance of IIR, SIR, AIR, and SIC, respectively. This work highlights the important roles of patchy mosaic patterns in affecting soil water redistribution and the stabilization of ecological systems, providing a scientific basis for vegetation selection in the process of vegetation restoration in water-limited regions.

Aboveground biomass determines canopy rainfall interception loss in Semiarid Grassland Communities

AbstractCanopy rainfall interception is one key hydrological process, affecting rainwater redistribution and effectiveness in semiarid regions. Canopy rainfall interception loss is jointly influenced by meteorology, vegetation and topography. The canopy water storage capacity (S), rainfall interception depth (Im) and ratio (I%) and vegetation characteristics, together with topographic factors of three grassland communities (dominated by Bothriochloa ischaemum, Lespedeza davurica and Artemisia gmelinii, respectively) were investigated on the Loess Plateau of China during the main growing season (June to September). Results showed that Im ranged from 0.55 to 0.89 mm and I% ranged from 6.14% to 12.1%, with the maximum values occurring in August for three communities, and A. gmelinii community had the largest Im (0.89 mm) and I% (12.1%). The Im and I% were positively correlated with aboveground biomass (AGB), coverage (Cov), leaf area index (LAI), community‐weighted mean height (CWMH) and altitude (Alt), but negatively correlated with slope degree and rainfall intensity (RI). Hierarchical partitioning analysis (HPA) showed that AGB had the highest contribution for Im (20.3%), while Alt had the highest contribution for I% (18.2%). The regression models based on forward selection could effectively predict the values of Im (R2 = 0.802, RMSE = 0.049) and I% (R2 = 0.546, RMSE = 1.434). Topographic factors (altitude, slope degree and aspect) indirectly influenced both Im and I% by modulating vegetation characteristics (AGB, Cov, etc.). All these indicated that aboveground biomass mainly determines grassland community rainfall interception loss in the semiarid Loess Plateau.

Interplays between plants and environmental factors determine pullout resistance on different revegetated slopes in mining areas

Plant roots play a crucial role in enhancing soil stability and protecting slopes during ecological restoration, particularly in mining areas where external-soil spray seeding is employed. However, the relationship between plant root pullout resistance and environmental factors on different types of slopes remains unclear. In this study, we investigated the interactions between the pullout resistance of a dominant species, Artemisia gmelinii, and environmental factors on three slope types (rocky, geotechnical, and soil) using multi-group structural equation modeling. Our findings reveal that the pullout resistance of plant roots was strongly influenced by various factors, including but not limited to biological factors such as plant height and biomass. It showed a positive correlation between soil silt content and soil nutrient levels. Notably, the pullout resistance on soil slopes was significantly higher than on rocky slopes. Furthermore, the impact of soil nutrients and texture on pullout resistance was more pronounced on geotechnical and soil slopes compared to rocky slopes. Multi-group structural equation modeling highlighted that among all environmental factors, slope gradient and underground biomass had the most significant influence on pullout resistance across all slope types. Specifically, slope gradient had a greater effect on soil slopes, whereas underground biomass played a more prominent role on rocky and geotechnical slopes. Overall, our study suggests that when implementing external-soil spray seeding in mining areas, it is crucial to consider the interplay between plant roots and environmental factors, including slope properties. This holistic approach is crucial for maximizing the effectiveness of plants in slope protection during eco-engineering projects.

Artemisia gmelinii Extract Attenuates Particulate Matter-Induced Neutrophilic Inflammation in a Mouse Model of Lung Injury.

Particulate matter (PM) induces and augments oxidative stress and inflammation, leading to respiratory diseases. Although Artemisia gmelinii Weber ex Stechm has antioxidant and anti-inflammatory effects, there are no reports on whether Artemisia gmelinii extract (AGE) regulates lung inflammation in a PM-induced model. Thus, we investigated the protective effects of AGE using a PM-induced mouse lung inflammation model. AGE significantly decreased the expression of inflammatory chemokines, neutrophil extracellular trap formation, and the total number of inflammatory cells in the bronchoalveolar lavage fluid (BALF). Furthermore, AGE attenuated lung inflammation through the suppression of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathway, while promoting the nuclear factor erythroid-2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) signaling pathway in lung tissues. Concordant with these observations, AGE suppressed inflammatory cytokines, chemokines, reactive oxygen species, NETosis, myeloperoxidase, and neutrophil elastase by decreasing the mRNA expression of High mobility group box 1, Runt-related transcription factor 1, and Kruppel-like factor 6 in differentiated HL-60 cells. In summary, our data demonstrated that AGE suppresses PM-induced neutrophil infiltration, lung damage, and pulmonary inflammation by suppressing NF-κB/MAPK signaling pathways and enhancing the NRF2/HO-1 signaling pathway. These findings suggest that AGE administration is an effective approach for preventing and treating PM-induced respiratory inflammation.

Comparisons of phenolic compounds and antioxidant activities during different growth stages in Artemisia gmelinii Weber ex Stechm with UPLC-QTOF/MS based on a metabolomics approach

Metabolomics approaches are becoming popular for a rational and efficient approach to standardize research including optimal harvest time determination to improve the values of plant raw materials. In this study, multivariate statistical analysis of metabolites from Artemisia gmelinii Weber ex Stechm (AG) by growth stage according to harvest time (from June to October) was performed by ultra-performance liquid chromatography (UPLC) coupled with quadrupole time of flight mass spectrometry (Q-TOF/MS). Secondary metabolite analysis through PCA provided clearly distinguishable patterns and qualitative R2X values (93.7%) for the corresponding markers. From the OPLS-DA, ten phenolic compounds were found as biomarkers exhibiting distinct patterns according to the harvesting periods (June-Aug: five phenolic acids, Aug-Oct: five flavonoids), and the contents of these phenolic compounds, well-known antioxidants, were increased according to the growth period (Oct > Aug > June). In conclusion, the harvesting time of plant raw materials could be sufficiently determined through the metabolomics study of secondary metabolites.

How root and soil properties affect soil detachment capacity in different grass–shrub plots: A flume experiment

Grasses and shrubs play important roles in preventing soil erosion. However, the mechanism of their impact on soil detachment is still unclear. Therefore, this study examined the following combinations of typical grass–shrub sample plots on the Loess Plateau: Caragana korshinskii (JJ), C. korshinskii and Agropyron cristatum (JC), C. korshinskii and Bothriochloa ischaemum (JB), and C. korshinskii and Artemisia gmelinii (JH). The variation characteristics of the soil detachment rate with depth (0–30 cm) and at different locations (0 cm, 50 cm) from the base of shrubs under a fixed flow rate and slope were explored. The spatial heterogeneity of the detachment rate in the grass–shrub plots was strong. In different plots, the soil detachment rate at 50 cm from the base of the shrub was relatively low. The ability of root length to reduce the detachment rate varied. In the JJ sample plot, the root length at the shrub base had a relatively strong ability to reduce the detachment rate, while it showed the opposite trend in the other plots. The ability to reduce the detachment rate was higher in the JC and JB plots at 0–5 cm than in the JH plots. However, at 20–30 cm, the opposite trend was observed. Overall, with the exception of the JC plots, the soil detachment rate in the other mixed plots was lower than that in single-species plots. In this study, soil aggregates and root length density were the main factors affecting the soil detachment rate. The combination of the two could also better calculate the soil detachment rate (R2 = 0.80). Compared with traditional regression methods, the back propagation neural network model had a relatively high R2 (0.86) when predicting the soil detachment rate. This study revealed the mechanisms underlying differences in soil detachment capacity in different grass–shrub sample plots.

Effect of roots on the soil detachment process in grassland and shrubland

AbstractPlant roots play an important role in reducing soil detachment and increasing soil erosion resistance. Current studies have mainly focused on the quantification of the soil detachment rate (SDR). However, few studies have been conducted to explore the variation in the SDR and root effects during the soil detachment process. In this study, undisturbed soil samples were collected from four shrublands (with the main species Caragana korshinskii, C. korshinskii mixed with Agropyron cristatum, C. korshinskii mixed with Bothriochloa ischaemum, and C. korshinskii mixed with Artemisia gmelinii) and three grasslands (with the main species B. ischaemum, B. ischaemum mixed with A. cristatum, and B. ischaemum mixed with A. gmelinii) on the Loess Plateau, China. The samples were subjected to flow scouring through hydraulic flume experiments under six different shear stresses. The duration of this experiment was 6 min, and the SDR of each minute was estimated. The results showed that the SDR of shrubland was higher than that of grassland in each detachment process. The dominant factors affecting SDR gradually changed from the root–soil composite properties to the hydrodynamic parameters in this process. The effect of roots on the SDR was stronger than that of soil properties in the root–soil composite. In the early detachment stage, the 0–2 mm fine roots had the strongest effect on the SDR, while it was affected by the combined effect of fine roots and coarse roots in the later stage. When the fibrous roots were mixed with the tap roots, the fibrous roots had a significant negative effect on the SDR and mainly affected the early detachment stage. However, the tap roots had a weak effect in all stages. With the detachment process, the soil erosion resistance first increased and then stabilized, and the variations were mainly concentrated from 0 to 3 min. The roots mainly affected the SDR and soil erosion resistance by influencing rill erodibility parameters.

Spatial distributions of soil nutrients affected by land use, topography and their interactions, in the Loess Plateau of China

Soil nutrient availability and their spatial distributions are strongly related to land use and landscape morphology. This study aims to address the knowledge gap regarding the interaction between these factors and the underlying mechanisms. We selected five land uses (grassland with Artemisia gmelinii, woodland with Robinia pseudoacacia, shrubland with Caragana korshinskii and Hippophae rhamnoides, and apple orchard with Malus pumila) and nine slope positions across hillslopes in the Loess Plateau, China, to investigate their combined effects on the contents and stocks of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP). Parametric and non-parametric statistical tests were conducted to determine the significant differences in the means or the medians of the soil nutrient variables. Results showed that the SOC and TN contents of shrubland with Caragana korshinskii were statistically significantly greater than those of the grassland (p < 0.05). SOC and TN contents generally decreased from the upper slope to the middle slope, and to the foot slope for the grassland, woodland and shrublands, and on the contrary, an increasing trend from the upper slope, to the middle slope, and to the foot slope was identified for the apple orchard. This study highlights that land use, slope position and their interaction have significant effects on the spatial distributions of soil nutrients. It provides essential empirical evidence for the identification of the optimal vegetation type and slope positions in land management and vegetation restoration activities.

Hydrological and erosion responses of steep spoil heaps to taproot and fibrous root grasses under simulated rainfalls

Spoil heaps, resulting from excavation and backfilling activities at construction sites, are one of the most important risk sources of soil erosion, threatening local ecosystems and even leading to geological disasters. However, after revegetation, spoil heaps can be transformed into available land resources such as cultivated land and forest land. Previous studies have reported the runoff and sediment reduction benefits of different vegetation measures on spoil heaps, while little information has been documented about what differences in the taproot and fibrous root grasses were transferred into the differences in hydrological and erosion processes. This study compared the effects of taproot (Artemisia gmelinii (A. gmelinii)) and fibrous root (Cynodon dactylon (C. dactylon)) grasses on soil erosion and runoff production processes and the reduction benefits of spoil heaps with silt loam soil. A series of rainfall events at three intensities (0.8, 1.2, and 1.8 mm min−1) were simulated on runoff plots (length of 3.0 m and width of 1.0 m) under treatments of A. gmelinii, C. dactylon, and bare soil (BS, as control) (each treatment was replicated), and the initial runoff time (IRT), saturated hydraulic conductivity, runoff rate (RR), flow velocity, and soil loss rate (SLR) were measured. The results showed that grasses delayed the IRTs on spoil heaps by 0.69–12.96 min compared BS, and the delay effects were more significant for fibrous root grass than for taproot grass. The soil loss reduction benefits (91.1 %) of the two kinds of grass were approximately 2.2 times greater than those of runoff volume reduction (42.1 %), and shear stress could be used to predict the soil loss rate following power functions (R2 = 0.72–0.85) for the grass-covered plots. The taproot grass exhibited a higher erosion reduction than fibrous root grass and is thus preferred to control the soil erosion of spoil heaps. Taproot grass has a greater stem diameter and can insert deeper into spoil heaps to consolidate the soil particles, which can improve roughness and hydraulic resistance, thereby producing a lower effective hydraulic shear stress that is directly exerted on soil particles. This study enhances the understanding of different grasses on the water erosion process and mechanism of spoil heaps and provides scientific guidance for selecting erosion control practices.

Artemisia gmelinii Extract Alleviates Allergic Airway Inflammation via Balancing TH1/TH2 Homeostasis and Inhibiting Mast Cell Degranulation.

A new terminology "combined allergic rhinitis and asthma syndrome (CARAS)" was introduced to describe patients suffering from both allergic rhinitis (AR) and asthma. The pathogenesis of allergic airway inflammation has been well known, with the main contribution of TH1/TH2 imbalance and mast cell degranulation. Artemisia gmelinii has been used as an herbal medicine with its hepaprotective, anti-inflammatory, and antioxidant properties. In this study, the effect of A. gmelinii extracts (AGE) on the ovalbumin (OVA)-induced CARAS mouse model was investigated. AGE administration significantly alleviated the nasal rubbing and sneezing, markedly down-regulated both OVA-specific IgE, IgG1, and histamine levels, and up-regulated OVA-specific IgG2a in serum. The altered histology of nasal and lung tissues of CARAS mice was effectively ameliorated by AGE. The AGE treatment group showed markedly increased levels of the TH1 cytokine interleukin (IL)-12 and TH1 transcription factor T-bet. In contrast, the levels of the TH2 cytokines, including IL-4, IL-5, IL-13, and the TH2 transcription factor GATA-3, were notably suppressed by AGE. Moreover, AGE effectively prevented mast cell degranulation in vitro and mast cell infiltration in lung tissues in vivo. Based on these results, we suggest that AGE could be a potential therapeutic agent in OVA-induced CARAS by virtue of its role in balancing the TH1/TH2 homeostasis and inhibiting the mast cell degranulation.

Vegetation affects gully headcut erosion processes by regulating runoff hydrodynamics in the Loess tableland region

Vegetation plays an important role in gully headcut erosion processes. However, it is still unclear how vegetation in the upstream area affects gully headcut erosion processes by changing the hydraulics. A series of in situ inflow scouring experiments were conducted on bare land plots and vegetation plots (including the upstream area, headwall, and gully bed) planted with Bothriochloa ischaemum (BI), Agropyron cristatum (AC), and Medicago sativa (MS) with clustered stems and Artemisia gmelinii (AG) with erect stems to investigate the influence of vegetation on the hydrodynamic parameters involved in gully headcut erosion processes. The results showed that, compared with bare land, vegetation increased the Manning roughness coefficient (n) and Darcy–Weisbach friction factor (f) in the upstream area by 0.2–2.5 times and 0.9–9.6 times, respectively, but reduced the runoff velocity in the upstream area and gully brink. However, the jet flow velocity at entry into the plunge pool increased rapidly after passing through the gully head. The influence of vegetation with clustered stems on roughness and runoff velocity was greater than that of vegetation with branched stems. At 3.6 m3/h inflow discharge, vegetation can increase the runoff shear stress of the upstream area. The energy consumption of the gully head, upstream area, and gully bed accounted for 74 to 76 %, 19 to 21 %, and 4 to 7 % of the total energy consumption, respectively. The four vegetation treatments reduced the gully headcut soil loss by 31 to 81 %, among which MS exhibited the highest reduction. The soil loss rate was positively correlated with the jet flow velocity and its kinetic energy, and the correlation was the best (R2 of 0.934 and 0.935, respectively, P < 0.01), presenting a logarithmic trend. These results are helpful to deepen the understanding of the roles of vegetation in regulating runoff hydraulic action during gully headcut erosion.

Differential effects of soil texture and root traits on the spatial variability of soil infiltrability under natural revegetation in the Loess Plateau of China

Soil infiltrability controls precipitation input to soil and plays a crucial role in regulating soil eco-hydrological processes and ecosystem production in water-limited areas worldwide. The effects of root traits on soil infiltrability have been widely investigated at individual sites, but root-soil interactions and their effects on soil water infiltration over large spatial scales remain poorly understood. This study aimed to identify the unique characteristics of soil infiltration processes and different contributions of soil texture and root morphological traits to soil infiltrability. For this purpose, 153 plots of natural revegetated land with two contrasting plant species (Artemisia gmelinii Web. with tap root systems and Stipa bungeana Trin. with fibrous root systems) and bare land were selected in three regions along a texture gradient in the Loess Plateau of China. The results showed a distinct spatial variability of soil infiltration rates across the three regions with soil texture explaining the variability more strongly than plant species at several infiltration stages. Rooted soils had higher infiltration rates than bare soils, with nonsignificant inter-species difference under three soil texture types. Furthermore, soil texture and root morphological traits explained 92.03% and 74.75% of the total variance of soil properties (soil organic matter, aggregate stability, and soil porosity), and their interaction effects (73.09%), accounted for a considerable proportion. These findings suggest that soil texture and root morphological traits indirectly affect soil infiltrability by modulating soil properties, with soil texture having a higher contribution. In addition, the effects of root morphological traits on soil infiltrability were found to be dependent of soil texture on the regional scale. Therefore, the effects of soil texture and root-soil interaction deserves further attention in assessing soil hydrological processes on large spatial scales in the future.

The contribution of understory and Compositae species to canopy storage capacity of semiarid grassland communities on the Loess Plateau

AbstractCanopy rainfall interception reduces the effectiveness of limited rainfall resources in arid and semiarid regions. To clarify the effects of species composition and community vertical structure on canopy storage capacity, the artificial wetting and simulated rainfall methods were used to determine the species (C) and community (Cmax) water storage, respectively, in three typical grassland communities on the semiarid Loess Plateau. Results indicated that water storage capacity of 31 grassland species ranged from 0.47 to 3.73 g g−1, with an average of 1.60 g g−1, and leaf storage capacity was significantly higher than the stem. Plant storage capacity was correlated with leaf traits (including leaf fresh weight, length and area). Canopy storage capacity of three grassland communities (Bothriochloa ischaemum, Artemisia gmelinii and Lespedeza davurica) ranged from 0.77 to 1.09 mm and were positively correlated with community leaf area index (LAI), coverage and leaf dry biomass. Leaf and stem water storage accounted for 57.6% and 42.4% of the total community, respectively. The water storage of Compositae, Gramineae, Leguminosae and other species accounted for 35.5%, 27.0%, 23.4% and 14.1%, respectively. The plants in the community with heights of &gt;40, 20–40 and 0–20 cm contributed 5.8%, 30.3% and 63.9% of the water storage, respectively. The field observed canopy storage capacity was significantly higher than the estimated value through scaling up the individual storage data to the community, revealing complex community structure and species composition may increase actual rainfall interception. These results highlighted the species at 0–20 cm height was the key component affecting canopy water storage, and Compositae species may intercept more rainfall within the community, which imply that reducing the understory or Compositae species composition of grassland community would be helpful for increasing limited rainfall partitioning to soil in the drought area.

Content of some heavy metals in plants of Artemisia gmelinii Web. et Stechm (Transbaikal Territory)

The paper presents research data on the content of chemical elements (Fe, Mn, Ti, Zn, Cu, Pb, Cr, Ni) in a plant Artemisia gmelinii Web. eх Stechm, growing on the territory of the Transbaikal Territory. It has been established that most of the studied elements are concentrated in the aboveground phytomass of the plant. The maximum average concentrations are recorded for iron, manganese and titanium. Only zinc accumulates in the leaves of the studied species. Nutrients chemical elements as copper and nickel are evenly distributed throughout the plant. For copper, zinc and lead, exceed-ances of the maximum permissible concentrations were recorded (for dry vegetables).

Variations in Plant Water Use Efficiency Response to Manipulated Precipitation in a Temperate Grassland

Water use efficiency (WUE) plays important role in understanding the interaction between carbon and water cycles in the plant-soil-atmosphere system. However, little is known regarding the impact of altered precipitation on plant WUE in arid and semi-arid regions. The study examined the effects of altered precipitation [i.e., ambient precipitation (100% of natural precipitation), decreased precipitation (DP, −50%) and increased precipitation (IP, +50%)] on the WUE of grass species (Stipa grandis and Stipa bungeana) and forb species (Artemisia gmelinii) in a temperate grassland. The results found that WUE was significantly affected by growth stages, precipitation and plant species. DP increased the WUE of S. grandis and S. bungeana generally, but IP decreased WUE especially in A. gmelinii. And the grasses had the higher WUE than forbs. For different growth stages, the WUE in the initial growth stage was lower than that in the middle and late growth stages. Soil temperature, available nutrients (i.e., NO3–, NH4+, and AP) and microorganisms under the altered precipitations were the main factors affecting plant WUE. These findings highlighted that the grasses have higher WUE than forbs, which can be given priority to vegetation restoration in arid and semi-arid areas.

The role of roots traits of climax community species to shear strength in the Loess Hilly Region, China

the climax community species, especially their roots, have been found very helpful to increase slope stability and reinforce the soil on the Loess Plateau of China. However, the effect of root-soil shear resistance is poorly understood on plant roots mechanical traits and chemical compositions on the Loess Plateau. Thus, this study evaluated the correlations among root mechanical properties, root chemical compositions and root parameters traits, and effects of root traits on soil shear resistance. In this study, the roots of climax community species (Bothriochloa ischaemum (L.) Keng. (B. ischaemum), Carex tristachya Thunb. (C. tristachya), Artemisia gmelinii Web. (A. gmelinii), and Artemisia giraldii Pamp. (A. giraldii)) were subjected to be a series of laboratory tests of biochemical, biomechanical and direct shear strength with different soil layers. The findings of the study revealed that (1) Over 65% of the total measured root parameter traits were distributed in the upper 20 cm of the soil, and they decreased with increasing soil layer. There was the highest Tr by B. ischaemum as a failure (386.5 MPa), followed by C. tristachya (30.97 MPa), A. gmelinii (24.67 MPa), A. giraldii (8.95 MPa). The tensile properties (Tr (root tensile strength) and Tf (tensile force)) were significantly correlated with root diameter. The contents of root lignin were significantly correlated with root diameter while cellulose and hemicellulose showed no obvious trend with root diameter. Tr was significantly positive correlation from cellulose and lignin. (2) The presence of plant roots enhanced the soil cohesion by 13.34～115.05%. The soil cohesion is negatively correlated with the soil layers whether the root-soil composites or the soil without roots. (3) The root-soil composite cohesion can be explained by RSAD (root surface area density), followed by RLD (root length density) and D (root diameter), and the internal friction angle can be explained by Tr, followed by cellulose and lignin. These conclusions were provided theoretical guidance and data accumulation for the mechanical traits, soil reinforcement and slope stability of climax community species roots in the Loess Plateau of China.

Effects of soil surface electrochemical properties on soil detachment regulated by soil types and plants

Soil surface electrochemical properties play an important role in soil detachment. However, the effects of soil surface electrochemical properties on soil detachment have received little attention. This study selected three typical soil types (sandy loam, silt loam and silt clay loam) and two typical herbaceous plants (Stipa bungeana Trin. and Artemisia gmelinii Web. ex Stechm., with an abandoned cropland) to quantify the effects of varied soil surface electrochemical properties caused by soil types and plants on soil detachment on the Loess Plateau, China. A hydraulic flume test was conducted under five flow discharges (0.1, 0.2, 0.3, 0.4 and 0.6 L s−1) on a 15° slope. The results showed that large differences in soil surface electrochemical properties occurred among different soil types and plant species. The exchangeable sodium percentage (ESP), cation exchange capacity (CEC), specific surface area (S), surface charge density (σ0), surface potential (φ0) and surface electric field strength (E0) ranged from 1.02% to 2.26%, from 7.26 to 24.34 cmolc kg−1, from 8.32 to 147.38 m2 g−1, from 0.09 to 2.02C m−2, from −81.33 to −149.92 mV and from 1.23 × 108 to 28.46 × 108 V m−1, respectively. The soil detachment capacity (Dc) was significantly correlated with ESP (P < 0.01), E0 (P < 0.01) and |φ0| (the absolute value) (P < 0.05). Moreover, Dc exponentially increased with |φ0| (R2 = 0.99) and linearly increased with ESP (R2 = 0.85) and E0 (R2 = 0.95). Therefore, soil surface electrochemical properties greatly varied with soil types and plants and had a significant effect on soil detachment.