Search Results (214)

In plateau wetlands, the interactions of herbaceous roots with ectorhizosphere soil microorganisms represent an important way to realize their ecological functions. Global change-induced aridification of plateau wetlands has altered long-established functional synergistic relationships between plant roots and ectorhizosphere soil microbes, but we still know little about this phenomenon. In this context, nine typical wetlands with three different moisture statuses were selected from the eastern Tibetan Plateau in this study to analyze the relationships among herbaceous plant root traits and microbial communities and functions. The results revealed that drought significantly inhibited the accumulation of root biomass and surface area as well as the development of root volumes and diameters. Similarly, drought significantly reduced the diversity of ectorhizosphere soil microbial communities and the relative abundances of key phyla of archaea and bacteria. Redundancy analysis revealed that plant root traits and ectorhizosphere soil microbes were equally regulated by soil physicochemical properties. Functional genes related to carbohydrate metabolism were significantly associated with functional traits related to plant root elongation and nutrient uptake. Functional genes related to carbon and energy metabolism were significantly associated with traits related to plant root support and storage. Key genes such as CS,gltA, and G6PD,zwf help to improve the drought resistance and barrenness resistance of plant roots. This study helps to elucidate the synergistic mechanism of plant and soil microbial functions in plateau wetlands under drought stress, and provides a basis for evolutionary research and conservation of wetland ecosystems in the context of global change. Full article

Field bindweed (Convolvulus arvensis L.) is a competitive herbaceous perennial weed that reduces productivity in irrigated pastures. Grazing might reduce competition by field bindweed when it begins growth in the spring, thereby encouraging encroachment by desirable grass species during the summer. To test this hypothesis, a two-year study was conducted in two adjacent, privately owned, irrigated, warm-season perennial grass pastures (replicates) that were heavily infested with field bindweed. Study sites were near Tucumcari, NM, USA. The fields were grazed with exclosures to evaluate ungrazed management. Aboveground biomass of field bindweed, other weeds, and perennial grass were measured, and field bindweed plants were counted in May of 2018 and 2019. There was no difference between years for any variable. Other weed biomass and field bindweed biomass and plant numbers were reduced (p < 0.05) by grazing (61.68 vs. 41.67 g bindweed biomass m⁻² for ungrazed and grazed management, respectively, and 108.5 and 56.8 bindweed plants m⁻² for ungrazed and grazed management, respectively). Otherwise, perennial grass production was unaffected by either year or management. These results indicate that grazing can be an effective tool to reduce field bindweed competition in warm-season perennial grass pastures. Full article

Increasing soil carbon storage is an important strategy for achieving sustainable development. Enhancing soil carbon sequestration capacity can effectively reduce the concentration of atmospheric carbon dioxide, which not only contributes to the carbon neutrality goal but also helps maintain ecosystem stability. Based on 146 soil samples collected at plot locations selected across Beijing, we examined relationships between soil organic carbon (SOC) and key characteristics of urban forests, including their spatial structure and species complexity. The results showed that SOC in the topsoil with a depth of 20 cm was highest over forested plots (6.384 g/kg–20.349 g/kg) and lowest in soils without any vegetation cover (5.586 g/kg–6.783 g/kg). The plots with herbaceous/shrub vegetation but no tree cover had SOC values in between (5.586 g/kg–15.162 g/kg). The plot data revealed that SOC was better correlated with the physical structure than the species diversity of Beijing’s urban trees. The correlation coefficients (r) between SOC and five physical structure indicators, including average diameter at breast height (DBH), average tree height, basal area density, and the diversity of DBH and tree height, ranged from 0.32 to 0.52, whereas the r values for four species diversity indicators ranged from 0.10 to 0.25, two of which were not statistically different from 0. Stepwise linear regression analyses revealed that the species diversity indicators were not very sensitive to SOC variations among a large portion of the plots and were about half as effective as the physical structure indicators for explaining the total variance of SOC. These results suggest that urban planning and greenspace management policies could be tailored to maximize the carbon co-benefits of urban land. Specifically, trees should be planted in urban areas wherever possible, preferably as densely as what can be allowed given other urban planning considerations. Protection of large, old trees should be encouraged, as these trees will continue to sequester and store large quantities of carbon in above- and belowground biomass as well as in soil. Such policies will enhance the contribution of urban land, especially urban forests and other greenspaces, to nature-based solutions (NBS) to climate change. Full article

To investigate the remediation efficiency of different plant species on cadmium (Cd)-contaminated soil, this study conducted a pot experiment with two woody species (Populu adenopoda and Salix babylonica) and two herbaceous species (Artemisia argyi and Amaranthus hypochondriacus). Soils were collected from an abandoned coal mine and adjacent pristine natural areas within the dam-adjacent section of the Three Gorges Reservoir Area to establish three soil treatment groups: unpolluted soil (T1, 0.18 mg·kg⁻¹ Cd), a 1:1 mixture of contaminated and unpolluted soil (T2, 0.35 mg·kg⁻¹ Cd), and contaminated coal mine soil (T3, 0.54 mg·kg⁻¹ Cd). This study aimed to investigate the growth status of plants, Cd accumulation and translocation characteristics, and the relationship between them and soil environmental factors. Woody plants exhibited significant advantages in aboveground biomass accumulation. Under T3 treatment, the Cd extraction amount of S. babylonica (224.93 mg) increased by about 36 times compared to T1, and the extraction efficiency (6.42%) was significantly higher than other species. Among the herbaceous species, A. argyi showed the maximum Cd extraction amount (66.26 mg) and extraction efficiency (3.11%) during T2 treatment. While A. hypochondriacus exhibited a trend of increasing extraction amount but decreasing extraction efficiency with increasing concentration. With the exception of S. babylonica under T1 treatment (BCF = 0.78), the bioconcentration factor was greater than 1 in both woody (BCF = 1.39–6.42) and herbaceous species (BCF = 1.39–3.11). However, herbaceous plants demonstrated significantly higher translocation factors (TF = 1.58–3.43) compared to woody species (TF = 0.31–0.87). There was a significant negative correlation between aboveground phosphorus (P) content and root Cd (p < 0.05), while underground nitrogen (N) content was positively correlated to aboveground Cd content (p < 0.05). Soil total N and available P were significantly positively correlated with plant Cd absorption, whereas total potassium (K) showed a negative correlation. This study demonstrated that woody plants can achieve long-term remediation through biomass advantages, while herbaceous plants, with their high transfer efficiency, are suitable for short-term rotation. In the future, it is suggested to conduct a mixed planting model of woody and herbaceous plants to remediate Cd-contaminated soils in the tailing areas of reservoir areas. This would synergistically leverage the dual advantages of root retention and aboveground removal, enhancing remediation efficiency. Concurrent optimization of soil nutrient management would further improve the Cd remediation efficiency of plants. Full article

This study provides novel insight into herbaceous-layer dynamics across three distinct South African savanna bioregions (Central Bushveld, Lowveld, and Mopane) using a Total Count Quadrat approach to investigate species densities, community composition, diversity, and spatial patterns. A total of 196 unique herbaceous species were recorded across all bioregions. Contrary to typical expectations, our findings reveal no statistically significant differences in overall herbaceous density (ranging from 24.3 ± 2.31 to 32.0 ± 1.28 individuals/m²; F_2,6 = 1.89, p = 0.23), species richness (F_2,6 = 1.91, p = 0.23), or Shannon diversity (F_2,6 = 3.23, p = 0.11) among bioregions, suggesting a more complex interplay of environmental drivers beyond broad climatic gradients. However, there was significant within-bioregion spatial heterogeneity in density, notably in the Central Bushveld (F_2,87 = 4.96, p = 0.009) and Mopane (F_2,87 = 7.54, p < 0.001) regions, indicating important fine-scale variation, unlike in the Lowveld region (F_2,87 = 1.25, p = 0.292). Growth form analysis revealed that forbs consistently dominated species richness across all three bioregions (Central Bushveld: ~64%; Lowveld: ~70%; and Mopane: ~67%) and were also the dominant growth form by density in the Lowveld (54.3%) and Mopane (63.8%) regions. While numerical differences in grass density were observed, no statistically significant difference was found across bioregions (F_2,6 = 4.15, p = 0.07). Sedges consistently contributed a small proportion to both species richness and total density. Non-metric multidimensional scaling further revealed patterns of dispersion in herbaceous community compositions between the Lowveld and Mopane regions, with Central Bushveld communities exhibiting greater variability. These findings underscore the critical ecological importance of forbs in South African savannas, not only for biomass but also for driving herbaceous diversity and highlighting the necessity of considering fine-scale spatial variation in future ecological research and conservation strategies. Full article

This paper aims to fill a gap in relation to herbaceous biomass, which is the second most important source of biomass used for the production of solid biofuels in the form of pellets. Our research focuses on the final stage of compacted fuel production, specifically on the pressure densification of biomass into pellets. This review was conducted using bibliometric techniques. This analysis included searching indexed publications in the Web of Science—Core Collection and Scopus databases. The time range of the searched data was 1991–2024. First, bibliometric data were collected and quantitative analyses were performed. The next stage consisted of analyzing keywords from the authors’ publications using the VOSviewer program. The generated term maps allowed for the analysis of the frequency of keywords in different years and the most frequently cited ones, which enabled the identification of current research topics and the evolution of trends. Based on the collected data, applications, process parameters and raw materials used in the biomass densification process were determined. Following the bibliometric analysis, detailed analyses were carried out on the factors influencing the pressure compaction process. Full article

In recent decades, a significant decline in arthropods’ abundance and biodiversity, as a consequence of intensive agricultural practices and reductions in their natural environments, has been observed. While landscape-scale biodiversity studies are well documented in the literature, the impact of field-level agricultural management remains less understood. To address this gap, a sampling of diversity was carried out through Malaise traps on five agricultural surfaces with different management schemes: two characterized by the presence of trees (Populus L. spp. and Eucalyptus spp.), two herbaceous fields in different development stages (flowering Carthamus tinctorius L. and stubble of Triticum aestivum), and one mixed system (an agroforestry plantation composed of Populus L. spp. and Carthamus tinctorius L.). Data collection focused on evaluating the total animal biomass (weight and number) and the richness and evenness components of diversity using Shannon and Simpson indices at the Order level. The sampled arthropods belonged to six Orders of Insecta and one Order of Arachnida. The agroforestry system had a higher total animal biomass, in terms of weight, than the other treatments (61.24% higher than in the eucalyptus system, 58.91% higher than in the wheat stubble, 42.63% higher than in the flowering safflower system, and 11.63% higher than in the poplar plantation), with the number of total arthropods following a similar trend. The results demonstrated that the biomass, richness, and evenness of the collected arthropods varied according to the management practices applied, and higher values were recorded in the agroforestry system. Although preliminary, the findings suggest the suitability of mixed systems for sustaining higher diversity than traditional monoculture management schemes. Full article

The objectives were to evaluate the energy potential of biomass and pellets produced from five underutilized herbaceous and woody plant species in México and Colombia; characterize pellet quality parameters; and calculate the preliminary production costs and energy requirement during the densification process. Harvest and sawmill residues were obtained for five non-timber and woody plant species. The volatile compounds, ash, and fixed carbon were evaluated, as well as the higher heating value (HHV) and pellet impact resistance (PIR); in addition, lignin, hemicellulose, and cellulose were quantified. The data were analyzed using descriptive statistics, including mean and standard deviation. The volatile compounds ranged from 65.9–77.5%, ash 2.5–17.2%, fixed carbon 5.4–19.9%, HHV 16.4–21.9 MJ kg⁻¹, and PIR (0.6–99.1%). Considerable intra- and inter-specific differences were observed for all the variables, which expanded the options for the selection of biomass sources used in bioenergy production. Biomass processing costs ranged from 675.9 to 679.3 EUR t⁻¹. Optimization of these processes is required to implement more efficient technologies that significantly reduce operating costs in biomass use in biofuel industry. The systematic study of different plant species, both introduced and native, will provide new sources of biomass to produce bioenergy, fertilizers, and other organic inputs. Full article

Grapevine root distribution and density influence mineral and water absorption and are affected by soil management and the use of cover crops. This study, conducted in a ten-year-old commercial Mediterranean vineyard with desiccant-managed inter-rows, compares the effects of three different soil management practices—minimum tillage (MT), spontaneous natural covering (NC), and a commercial grass mixture (GM)—on root development in Montepulciano vines grafted onto Kober 5BB rootstocks. Root length, diameter, and weight across different soil layers were analyzed by digging trenches. The results show that thin roots, primarily responsible for water and nutrient absorption, ensure greater soil volume exploration, while medium-to-large roots contribute mainly to root biomass. The presence of cover crops reduces root development in the upper soil layers due to competition with herbaceous species; however, this promotes deeper root exploration and increases the total root length per plant. In the deeper soil layers, root growth is limited by higher soil compaction. Tillage enhances the development of medium-to-large roots and increases the total root biomass per plant. In conclusion, soil management influences vine root development, and competition from cover crops stimulates the growth of absorbing roots in deeper soil layers. Full article

The densities of carbon, nitrogen, and phosphorus (C-N-P) reflect the adaptation and response of desert plants to hyper-arid environments. However, the allocation strategies for biomass and C-N-P densities among various plant life forms remain poorly understood. This study involved the collection of samples representing both aboveground and belowground biomass (to depths of 200 cm) from three desert plant species—both herbaceous and shrubby—and evaluating their C-N-P densities. The investigation focused on the distribution strategies and drivers influencing total C-N-P densities within the plant–soil system. The results indicated that the biomass of the shrub Tamarix ramosissima (8.88 ± 1.22 kg m⁻²) was significantly greater than that of the herbaceous plants Alhagi sparsifolia (0.96 ± 0.15 kg m⁻²) and Karelinia caspia (0.72 ± 0.09 kg m⁻²). The total C density among the three species was observed as follows: T. ramosissima (9.26 ± 0.99 kg m⁻²) > A. sparsifolia (6.21 ± 0.85 kg m⁻²) > K. caspia (6.18 ± 1.12 kg m⁻²). Notably, no significant differences were detected in the total N and P densities across the species. Additionally, for A. sparsifolia and K. caspia, the roots exhibited greater biomass and C-N-P densities. Further analysis revealed that soil pools accounted for 56.34–95.10% of total C density, 90.39–98.63% of total N density, and 99.86–99.97% of total P density in the plant–soil system. The order of total C-N-P densities was established as C > P > N, decoupling total P density from other environmental factors. Total C and N densities in the three plant species were predominantly influenced by soil physicochemical properties, with biotic factors and microbial biomass playing secondary roles. This study improves the understanding of C-N-P densities strategies of dominant vegetation for restoration and sustainable management in hyper-arid deserts. Full article

Retention forestry creates anthropogenic ecotones that diversify forest landscapes in terms of age and biomass. Such diversification can have ambiguous ecological impacts, raising uncertainties, particularly for black alder swamp woodlands, which are considered sensitive and are prioritized in EU conservation policy. This study aimed to examine the effects of adjacent clear-cutting on ground cover vegetation in 12 black alder stands in the hemiboreal zone in Latvia 11 to 120 years since the harvest. Ground cover vegetation was recorded by species along 40 m transects. The effects of the time since adjacent stand harvesting and exposure to the edge on species richness and Shannon diversity were assessed using linear mixed-effects models. A detrended correspondence analysis was used to explore the main environmental gradients. A total of 103 species were recorded: 15 in the tree and shrub layer, 66 in the herbaceous layer, and 22 in the moss and lichen layer. The exposure to the adjacent stand had a moderate positive effect on species diversity, while the effects of edge age were complex and varied by stand type. The scale of disturbance (the absolute length of the analyzed edge), rather than edge age or exposure, had the most pronounced effect on ground cover vegetation composition, suggesting persistent secondary edge effects that should be considered in forest management and conservation planning. Full article

Tall fescue (Festuca arundinacea Schreb.) is a herbaceous species that is commonly used for ecological slope restoration in China. However, water scarcity often constrains its growth due to the unique site conditions of steep slopes and climate-induced drought stress. This study aims to compare the ameliorative effects of silicon nanoparticles (Si NPs) and cellulose nanocrystals (CNCs) on drought stress in tall fescue and to elucidate their underlying mechanisms of action. The results indicated that drought stress impaired photosynthesis, restricted nutrient absorption, and increased oxidative stress, ultimately reducing biomass. However, Si NPs and CNCs enhanced drought tolerance and promoted biomass accumulation by improving photosynthesis, osmotic regulation, and antioxidant defense mechanisms. Specifically, Si NP treatment increased biomass by 48.71% compared to drought-stressed control plants, while CNCs resulted in a 33.41% increase. Transcriptome sequencing further revealed that both nanomaterials enhanced drought tolerance by upregulating genes associated with photosynthesis and antioxidant defense. Additionally, Si NPs improved drought tolerance by stimulating root growth, enhancing nutrient uptake, and improving leaf structure. In contrast, CNCs play a distinct role by regulating the expression of genes related to cell wall synthesis and metabolism. These findings highlight the crucial roles of these two nanomaterials in plant stress protection and offer a sustainable strategy for the maintenance and management of slope vegetation. Full article

The intra-plant plasticity of leaves plays a vital role in enabling plants to adapt to changing climatic conditions. However, limited research has investigated the extent of intra-plant leaf trait variation and leaf biomass allocation strategies in herbaceous plants. To address this gap, we collected a total of 1746 leaves from 217 Lamium barbatum Siebold and Zucc. plants and measured their leaf dry mass (M) and leaf area (A). Leaves were categorized by vertical position (upper vs. lower canopy layer) and leaf–shoot orientation (east, south, west, north). ANOVA with Tukey’s HSD test was used to compare differences in M, A, and leaf dry mass per unit area (LMA). Reduced major axis regression was employed to evaluate the scaling relationship between M and A, and the bootstrap percentile method was used to determine differences in scaling exponents. The data indicated that: (i) M, A, LMA, and the scaling exponents of M versus A did not differ significantly among leaf–shoot orientations, and (ii) lower layer leaves exhibited significantly greater M, A, and LMA than upper layer leaves, but their scaling exponents were significantly smaller. These findings highlight that plant vertical growth brings significant intra-plant plasticity in leaf traits and their scaling relationships in herbaceous plants. This plasticity differs from that observed in trees, but is also critical for balancing weight load and optimizing light-use efficiency, potentially enhancing stress resilience in herbaceous plants. Full article

Soil active nitrogen (N) fractions are essential for plant growth and nutrient cycling in terrestrial ecosystems. While previous studies have primarily focused on the impact of vegetation restoration on soil active nitrogen in karst ecosystems, the role of microclimate variation in rocky desertification areas has not been well explored. This study investigates soil active nitrogen fractions and key biotic and abiotic factors across four grades of rocky desertification—non-rocky desertification (NRD), light rocky desertification (LRD), moderate rocky desertification (MRD), and intense rocky desertification (IRD)—within two distinct microclimates: a dry-hot valley and a humid monsoon zone in the karst region of Guizhou Province, China. We evaluate soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), soil nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), microbial biomass nitrogen (MBN), soluble organic nitrogen (SON), and plant diversity. Results showed that SOC, TN, and TP were significantly higher in IRD areas. Soil NO₃⁻-N, MBN, and SON initially decreased before increasing, with consistent MBN growth in the dry-hot valley. NH₄⁺-N did not differ significantly under NRD but was higher in the dry-hot valley under LRD, MRD, and IRD. The dry-hot valley had higher MBN and SON across most desertification grades. Microclimate significantly influenced soil active N, with higher levels in the dry-hot valley under LRD and MRD conditions. Plant diversity and regeneration varied markedly between the microclimates. In the dry-hot valley, Artemisia dominated herbaceous regeneration, especially in MRD areas. Conversely, the humid monsoon zone showed more diverse regeneration, with Artemisia and Bidens prevalent in MRD and NRD grades. Despite declining plant diversity with desertification, the humid monsoon zone displayed greater resilience. These findings highlight the role of microclimate in influencing soil nitrogen dynamics and plant regeneration across rocky desertification gradients, offering insights for restoration strategies in karst ecosystems. Full article

Afforestation is regarded as a crucial approach to enhancing terrestrial carbon sinks. Nevertheless, in ecologically fragile regions, the impacts of afforestation on carbon in biomass and soil remain highly uncertain. This study employed field investigations to explore the effects of forestry ecological projects on carbon stocks in biomass and soil within the Qinghai–Tibet Plateau, and to deeply analyze its key influencing factors. The key findings are summarized as follows: (1) The total vegetation carbon stocks of arbor forests and shrub forests (ranging from 7.7 to 24.0 Mg/ha) are 1.3–6.8 times that of grasslands (ranging from 3.5 to 6.1 Mg/ha). Afforestation-induced changes in biomass carbon are primarily attributed to the increase in carbon storage within the arbor-shrub layer, while exhibiting negligible effects on herbaceous layer carbon. (2) The soil organic carbon (SOC) stocks (0–100 cm depth) of forestland, shrubland, and grassland are 39.6–64.5 Mg/ha, 40.7–100.2 Mg/ha, and 43.1–121.9 Mg/ha, respectively. There are no significant differences in SOC stocks among shrubland, forestland, and grassland at either the 10- or 25-year development stage. The SOC stocks of 40-year-old shrubland and forestland are 1.5 and 2.3 times that of grassland, respectively. (3) For 10-year-old and 25-year-old arbor and shrub afforestation, biomass carbon increased while SOC decreased, showing a trade-off. In the case of 40- year-old afforestation, both biomass carbon and SOC increased synergistically. (4) Results from the random forest analysis indicate that the understory herbaceous diversity in this region has a significant impact on biomass carbon sequestration, and that soil total nitrogen, ammonium nitrogen, and nitrate nitrogen determine SOC sequestration. (5) Partial least squares analysis further demonstrates that afforestation promotes the retention of SOC stocks by increasing soil nutrients (especially nitrogen and nitrogen availability). Afforestation in alpine and arid regions, especially 40-year shrub afforestation, holds great carbon sequestration potential. The supplementation of soil nitrogen and phosphorus can enhance the carbon sequestration of this system. Full article