Belowground Biomass Research Articles

Bacterial and fungal root endophytes alter survival, growth, and resistance to grazing in a foundation plant species.

Plants host an array of microbial symbionts, including both bacterial and fungal endophytes located within their roots. While bacterial and fungal endophytes independently alter host plant growth, response to stress and susceptibility to disease, their combined effects on host plants are poorly studied. To tease apart interactions between co-occurring endophytes on plant growth, morphology, physiology, and survival we conducted a greenhouse experiment. Different genotypes of Spartina alterniflora, a foundational salt marsh species, were inoculated with one bacterial endophyte, Kosakonia oryzae, one fungal endophyte, Magnaporthales sp., or co-inoculated. Within the greenhouse, an unplanned herbivory event occurred which allowed insight into the ways bacteria, fungi, and co-inoculation of both endophytic microbes alters plant defense chemicals and changes herbivory. Broadly, the individual inoculation of the bacterial endophyte increased survival, whereas the fungal endophyte increased plant growth traits. Following the herbivory event, the proportion of stems grazed was reduced when plants were inoculated with the individual endophytes and further reduced when both endophytes were present. Across genotypes, anti-herbivore defense chemicals varied by individual and co-inoculation of endophytes. Bacterial inoculation and genotype interactively affected above:below-ground biomass and S. alterniflora survival of ungrazed plants. Overall, our results highlight the variable outcomes of endophyte inoculation on Spartina growth, morphology, phenolics, and survival. This study furthers our understanding of the combined effects of symbionts and plant multitrophic interactions. Further, exploring intra and inter specific effects of plant--microbe symbiosis may be key in better predicting ecosystem level outcomes, particularly in response to global change.

Drivers of biomass stocks and productivity of tropical secondary forests.

Young tropical secondary forests play an important role in the local and global carbon cycles because of their large area and rapid biomass accumulation rates. This study examines how environmental conditions and forest attributes shape biomass compartments and the productivity of young tropical secondary forests. We compared 36 young secondary forest stands that differed in the time since agricultural land abandonment (2.3-3.6 years) from dry and wet regions in Ghana. We quantified biomass stocks in living and dead stems, roots, and soil, and aboveground biomass and litter productivity. We used structural equation models to evaluate how macroclimate, soil nutrients (N, P), and forest attributes (structure, diversity, and functional composition) affect ecosystem functioning. After three years of succession, tropical wet forests stored on average 115 t biomass ha-1 (the sum of aboveground living and dead biomass, belowground fine root biomass, and soil organic matter), and dry forests stored 99 t ha-1. These values represent 31% (in the wet forest) and 39% (in the dry forest) of the biomass compared with neighboring old-growth forests. The majority of forest ecosystem biomass was stored in the soil (70%) and aboveground living vegetation (25%). Macroclimate strongly shaped forest attributes, which in turn determined biomass stocks and productivity. Soil phosphorus strongly increased litter production and soil organic matter, confirming that it is a limiting element in tropical ecosystems. Tree density and species diversity increased forest biomass stocks, suggesting crown packing and complementary resource use enhance forest functioning. A more conservative trait composition (high wood density) increased biomass stocks but reduced productivity, indicating that quantity, identity, and quality of species affect ecosystem functioning.

Evaluation of Carbon Sequestration Potential of Different Melia Germplasms in Eastern Dry Zone of Karnataka, India

Melia dubia is one of the best agroforestry tree species, which is known for its faster growth rate and biomass accumulation. To maintain ecological balance and sustainability carbon sequestration plays an important role, hence this study aimed at identifying the best suitable Melia germplasm for Eastern dry zone of Karnataka. The present research was conducted from April, 2023 to July, 2024 in Agroforestry field unit, University of Agricultural Sciences, Bangalore. Randomized block design was used for the experiment. Evaluation of 15 Melia germplasms revealed that highest tree height was recorded in MD-173 (16.06 m) and lowest in MD-129 (12.31 m). Girth at breast height (GBH) was highest in MTP-3 (97.94 cm) and lowest in MD-135 (60.35 cm). Tree volume was highest in MTP-3 (328.6 m3 ha-1) and was on par with MTP-1 (314.4 m3 ha-1) and MD-138 (307.4 m3 ha-1) whereas, significantly lower tree volume was found in MD-135 (106.0 m3 ha-1). The above ground biomass, belowground biomass, total biomass and total biomass carbon were found highest in MTP-3 (197.2 t ha-1, 51.3 t ha-1, 248.6 t ha-1 and 124.2 t ha-1 respectively), and significantly lowest were found in MD-135 (63.6 t ha-1, 16.5 t ha-1, 80.1 t ha-1 and 40.1 t ha-1 respectively). MTP-3 consistently exhibited the highest biomass CO₂ values across all intervals, reaching a remarkable 455.9 t ha⁻¹ at 81 months followed by MTP-1 (436.1 t ha⁻1). MD-138 (426.4 t ha⁻¹), MD-157 (375.9 t ha⁻¹), and MD-164 (375.7 t ha⁻¹) were found to be intermediate CO2 accumulators. Lowest carbon sequestration potential was found in MD-135 (147.1 t ha-1), MD-174 (209.8 t ha-1) and MD-129 (236.3 t ha-1). MTP-3 followed by MTP-1 and MD-138 were more suitable for Eastern dry zone of Karnataka.

Increasing plant diversity enhances soil organic carbon storage in typical wetlands of northern China.

Soil organic carbon plays an important role in climate change mitigation, and can be strongly affected by plant diversity. Although a positive effect of plant diversity on soil organic carbon storage has been confirmed in grasslands and forests, it remains unclear whether this effect exists in wetlands. In this study, we investigated plant diversity, soil properties and soil organic carbon across five typical wetlands of northern China, to test the effect of plant diversity on soil organic carbon and clarified the regulators. Increasing plant diversity significantly increased belowground biomass of wetland plant communities, and both soil organic carbon content and storage were significantly positively related to wetland plant diversity. The positive effect of plant diversity was influenced by belowground biomass of wetland plant communities, soil microbial biomass carbon, and soil properties, especially soil water content and bulk density. The structural equation model showed that soil organic carbon storage was dominantly affected by microbial biomass carbon, plant diversity and biomass, with standardized total effects of 0.66 and 0.47, respectively, and there was a significant positive relationship between soil organic carbon and microbial biomass carbon. These results suggest that increasing plant diversity can potentially promote the ability of wetlands to store organic carbon in soils. The findings highlight the importance of plant diversity on soil organic carbon in wetland ecosystems, and have implications for managing wetlands to increase carbon sinks and to mitigate global climate change.

Capturing spatiotemporal variation in salt marsh belowground biomass, a key resilience metric, through geoinformatics

AbstractThe Belowground Ecosystem Resiliency Model (BERM) is a geoinformatics tool that was developed to predict belowground biomass (BGB) of Spartina alterniflora in salt marshes based on remote sensing of aboveground characteristics and other readily available hydrologic, climatic, and physical data. We sought to characterize variation in S. alterniflora BGB over both temporal and spatial gradients through extensive marsh field observations in coastal Georgia, USA, to quantify their relationship with a suite of predictor variables, and to use these results to improve performance and expand the parameter space of BERM. We conducted pairwise comparisons of S. alterniflora growth metrics measured at nine sites over 3–8 years and found that BGB grouped by site differed in 69% of comparisons, while only in 21% when grouped by year. This suggests that BGB varies more spatially than temporally. We used the BERM machine learning algorithms to evaluate how variables relating to biological, climatic, hydrologic, and physical attributes covaried with these BGB observations. Flooding frequency and intensity were most influential in predicting BGB, with predictor variables related to hydrology composing 61% of the total feature importance in the BERM framework. When we used this expanded calibration dataset and associated predictors to advance BERM, model error was reduced from a normalized root‐mean‐square error of 13.0%–9.4% in comparison with the original BERM formulation. This reflects both an improvement in predictive performance and an expansion in conditions for potential model application. Finally, we used regression commonality analysis to show that model estimates reflected the spatiotemporal structure of BGB variation observed in field measurements. These results can help guide future data collection efforts to describe landscape‐scale BGB trends. The advanced BERM is a robust tool that can characterize S. alterniflora productivity and resilience over broad spatial and temporal scales.

Effects of Prescribed Burns on Soil Respiration in Semi-Arid Grasslands

Carbon fluxes are valuable indicators of soil and ecosystem health, particularly in the context of climate change, where reducing carbon emissions from anthropogenic activities, such as forest fires, is a global priority. This study aimed to evaluate the impact of prescribed burns on soil respiration in semi-arid grasslands. Two treatments were applied: a prescribed burn on a 12.29 ha paddock of an introduced grass (Eragostis curvula) with 11.6 t ha−1 of available fuel, and a simulation of three fire intensities, over 28 circular plots (80 cm in diameter) of natural grasslands (Bouteloua gracilis). Fire intensities were simulated by burning with butane gas inside an iron barrel, which represented three amounts of fuel biomass and an unburned treatment. Soil respiration was measured with a soil respiration chamber over two months, with readings collected in the morning and afternoon. Moreover, CO2 emissions by combustion and productivity after fire treatment were quantified. The prescribed burns significantly reduced soil respiration: all fire intensities resulted in a decrease in soil respiration when compared with the unburned area. Changes in albedo increased the soil temperature; however, there was no relationship between changes in temperature and soil respiration; in contrast, precipitation highly stimulated it. These findings suggest that fire, under certain conditions, may not lead to more CO2 being emitted into the atmosphere by stimulating soil respiration, whereas aboveground biomass was reduced by 60%. However, considering the effects of fire in the long-term on changes in nutrient deposition, aboveground and belowground biomass, and soil properties is crucial to effectively quantify its impact on the global carbon cycle.

Root Biomass Allocation and Carbon Sequestration in Urban Landscaping Tree Species in South Korea

The quantification of urban tree biomass allocation has primarily relied on estimations using allometric equations (AEs) developed for nondestructive harvest methods. However, the lack of harvest-based AEs that account for belowground biomass, nutrient concentration, and annual growth rates poses challenges in accurately quantifying the greenhouse gas inventory for urban land uses. In this study, we aimed to develop AEs using a log-transformed linear model for eight urban landscaping tree species, taking into account belowground biomass. We purchased 117 urban landscaping trees from tree farms in South Korea and investigated their biomass fractions, carbon and nutrient concentrations, and annual growth rate using a destructive method. We also developed AEs for different tree compartments using diameter at breast height as an independent variable. The AEs obtained exhibited high suitability, as evidenced by their high R2 values (0.853–0.982 and 0.806–0.923 for aboveground and belowground biomass, respectively). The mean belowground biomass fraction across the different species was approximately 30%, suggesting that urban trees could allocate more belowground biomass than forest trees. Conversely, carbon and nitrogen concentrations varied significantly across species and compartments, and the mean annual carbon sequestration rate was 3.96 kg C year−1 tree−1. Therefore, the application of the AEs for urban trees may enhance the accuracy of the national greenhouse gas inventory for the settlement sector.

Plant Diversity, Productivity, and Soil Nutrient Responses to Different Grassland Degradation Levels in Hulunbuir, China

Grassland degradation could affect the composition, structure, and ecological function of plant communities and threaten the stability of their ecosystems. It is essential to accurately evaluate grassland degradation and elucidate its impacts on the vegetation–soil relationship. In this study, remote sensing data based on vegetation coverage were used to assess the degradation status of Hulunbuir grassland, and five different grassland degradation degrees were classified. Vegetation community composition, diversity, biomass, soil nutrient status, and their relationships in different degraded grasslands were investigated using field survey data. The results showed that grassland degradation significantly affected the species composition of the vegetation community. As degradation intensified, species richness declined, with the proportion of Gramineae and Legume species decreasing and Asteraceae species increasing. Additionally, the proportion of annual species initially increased and then decreased. Degradation also markedly reduced aboveground, belowground, and litter biomass within the communities. Soil moisture, electrical conductivity, organic carbon, total carbon, total potassium, and hydrolyzable nitrogen contents in non-degraded areas were higher than those in severely degraded areas. Conversely, soil total phosphorus content and bulk density gradually increased with degradation. Nitrate nitrogen and ammonium nitrogen levels in severely degraded soils were significantly higher than those in non-degraded soils. Plant diversity in the study area was significantly positively correlated with aboveground biomass and belowground biomass, and it positively correlated with soil nutrient total carbon and available carbon but negatively correlated with soil bulk density. Results of the partial least squares path model showed that grassland degradation had significant negative effects on plant diversity, soil nutrients, and biomass. Soil nutrients were the main factors affecting ecosystem productivity. The direct effect of plant diversity on biomass was not significant, suggesting that soil nutrients may play a more important role than plant diversity in determining biomass during grassland degradation. The results illustrated the relationships among soil nutrients, plant diversity, and biomass in degraded grasslands and emphasized the importance of an integrated approach in the effective management and restoration of degraded grasslands.

Harnessing Biomass and Blue Carbon Potential: Estimating Carbon Stocks in the Vital Wetlands of Eastern Sumatra, Indonesia

Global warming is a critical factor driving climate change, impacting every aspect of life on Earth. The escalating concentration of greenhouse gasses in the atmosphere, the primary contributor to global warming, necessitates immediate action through effective climate mitigation strategies. This study aimed to quantify the biomass and blue carbon stocks in the eastern coastal mangrove forests of North Sumatra and Aceh Provinces in Indonesia, focusing on key sites in Langkat, Deli Serdang, Batu Bara, Tanjung Balai, and Aceh Tamiang Regencies. We measured carbon stock in three carbon pools: biomass (above and below ground), necromass, and soil. By analyzing tree stands using parameters such as tree height and diameter at breast height within circular plots (7 m in radius, 125 m apart), we gathered fundamental data on forest structure, species composition, and above- and below-ground biomass. Additionally, we collected soil samples at various points and depths, measuring the amount of wood, stems, or branches (necromass) that fell to or died on the forest floor. Data were collected in plots along a line transect, comprising three transects and six circular plots each. Sixteen diverse mangrove species were found, demonstrating rich mangrove biodiversity. The mangrove forests in the five regencies exhibited significant carbon storage potential, with estimated average above-ground carbon ranging from 96 to 356 MgC/ha and average below-ground carbon from 28 to 153 MgC/ha. The estimated average deadwood carbon varied between 50 and 91 MgC/ha, while soil carbon ranged from 1200 to 2500 MgC/ha. These findings underscore the significant carbon storage potential of these mangrove forests, highlighting their importance to global carbon cycling and climate change mitigation. This research contributes to a broader understanding of mangroves as vital blue carbon ecosystems, emphasizing the necessity of conservation efforts such as forest restoration and rehabilitation to enhance their role in stabilizing coastal areas and improving global climate resilience.

Efficacy of multiple Brassica biofumigation techniques in the suppression of non‐native and native grass seedling emergence and productivity

AbstractNon‐native annual grasses are degrading rangelands in the western United States and of vital management importance. Novel management strategies are needed to extend current approaches. The aim of this study was to determine if biofumigation was a viable strategy to manage non‐native annual grasses (cheatgrass, Bromus tectorum and ventenata, Ventenata dubia). We tested the effect of Brassica juncea as ground seed meal, seed meal leachate, mustard straw, mustard straw leachate and cereal straw at increasing rates on the two non‐native species and two native perennial grasses (Idaho fescue, Festuca idahoensis and bluebunch wheatgrass, Pseudoroegneria spicata) in a growth chamber experiment. A solarization split treatment was applied using a clear cover to determine if solarization enhanced the biofumigant effect. We recorded the number of emergent seedlings after a 3‐week growth period, determined the effective dose 50%, and the above‐ and belowground biomass. Emergence was inhibited for all species using ground seed meal and seed meal leachate, with lower rates and higher consistency achieved with ground seed meal. Three species were inhibited using mustard straw leachate (not F. idahoensis). Mustard straw reduced emergence in all species but was not different from cereal straw. Solarization did not enhance the effects of the biofumigant for seed meal or mustard straw; conversely, emergence increased from the seed meal and mustard straw leachates under solarization. Responses in biomass varied across species and treatment. Biofumigation applied as ground seed meal may be a viable option for integrated weed management in rangelands, but field experimentation is necessary.

Interactive effects of rhizobia mutualism and herbivory on Vicia faba

ABSTRACT Background Species constantly interact with many organisms simultaneously, and multiple species interactions can have unique effects when combined and potentially cause resource and fitness trade-offs to the host. For example, extrafloral nectar can be an effective defence against herbivory, yet this nectar production can be influenced by abiotic and biotic environmental factors, including other mutualisms. Aims Here, we tested how traits associated with two different types of species interactions, herbivory and rhizobia-induced nodulation, may independently and interactively affect a host plant. Methods We manipulated the presence or absence of rhizobia at two different levels of herbivory in the field. We measured multiple plant growth traits and fitness responses, such as plant height, above- and below-ground biomass, total biomass, the ratio between above- and below-ground biomass, rhizobia nodule number, and average nodule size, extrafloral nectar volume, extrafloral nectar sugar concentration, as well as ant and arthropod visitation to explore the potential ant-plant mutualism. Results Rhizobia inoculation did not affect ant or other arthropod visitation but did alter plant traits associated with growth as well as decreased allocation to sugar concentration within extrafloral nectar. Extrafloral nectar volume remained nearly constant in nearly all treatments, except for a decrease when plants did not have rhizobia and were not subjected to herbivory. Finally, increased herbivory led to reduced nodule size but did not alter nodule number, indicating potential shifts in resource allocation. Conclusions Overall, multiple species interactions have compounding effects when combined, and plant traits alter differentially in response. In particular, we found a substantial benefit of rhizobia to the plants which did not result in either higher ant visitation or herbivory. However, greater herbivory did reduce plant growth, yet these effects varied depending on the presence or absence of rhizobia. This study demonstrates the importance of considering traits associated with multiple diverse species interactions simultaneously to better understand plant responses to environmental conditions.

Native Gramineae outperform Leguminosae in enhancing ecosystem multifunctionality during semiarid desert steppe restoration

The effects of reseeded native Gramineae and Leguminosae species on the multifunctionality of desert steppe have remained unclear. Therefore, we examined a semiarid desert steppe that was reseeded 5 years earlier with a dominant native Gramineae species, Agropyron mongolicum; a dominant native Leguminosae species, Lespedeza potaninii; and a 1:1 reseeded mixture of A. mongolicum × L. potaninii. We evaluated the changes in plant communities and soil properties and then quantified aboveground ecosystem multifunctionality (AEMF), belowground ecosystem multifunctionality (BEMF), and overall ecosystem multifunctionality (EMF) using an averaging approach. Compared with the native steppe without reseeding, both reseeded A. mongolicum and A. mongolicum × L. potaninii increased fine root volume, plant height, plant cover, aboveground biomass (AGB), belowground biomass (BGB), soil water storage (SWS), soil organic carbon, light fraction organic carbon, labile organic carbon, total nitrogen (TN), nitrate nitrogen, and total phosphorus (P), but decreased soil bulk density. However, reseeded L. potaninii increased coarse root volume, plant height, plant cover, AGB, BGB, and SWS but decreased plant richness, plant diversity, TN, and total P. In addition, reseeded A. mongolicum and A. mongolicum × L. potaninii increased AEMF, BEMF, and overall EMF, but reseeded L. potaninii only increased AEMF. Further analysis indicated that the fine roots played a crucial role in improving individual ecosystem functions and eventually in determining EMF. Therefore, the reseeding of a desert steppe with Gramineae species has greater potential than with Leguminosae species for improving EMF, since Gramineae species have greater fine roots volume than Leguminosae species.

Ethyl methanesulfonate (EMS) mediated dwarfing mutation provides a basis for CaCO3 accumulation by enhancing photosynthetic performance in Ceratostigma willmottianum Stapf.

Ceratostigma willmottianum Stapf is a unique chalk gland (salt-excreting) plant from China, with a salt gland structure that excretes white crystals of calcium carbonate (CaCO3), which has potential biomineralization and carbon sequestration functions. Due to the narrow distribution of wild germplasm resources, there is a lack of diversity of new varieties to satisfy commercial development and scientific exploration. Therefore, we used ethyl methanesulfonate (EMS) mutagenesis to obtain new dwarf mutant germplasm, and analysed it in terms of morphology, growth, photosynthesis, salt glands, and excretion traits. All four dwarfing mutant strains (DM1, DM2, DM3, and DM4) exhibited extreme dwarfing (62.28%, 62.28%, 74.55% and 61.68% reduction in plant height, respectively), faster growth, increased belowground root biomass, and earlier bud differentiation and flowering. Photosynthetic capacity was enhanced: chlorophyll content, maximum quantum yield of PSII (Fv/Fm), effective quantum yield of PSII (ΦPSII), photochemical quenching coefficient (qP), electron transfer rate (ETR), net photosynthesis (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs), and transpiration (Tr), were significantly higher in leaves of DM mutants. The density of salt glands per unit leaf area and average Ca2+ excretion rate of individual salt glands increased significantly (especially in DM2), and CaCO3 accumulation per unit leaf area was 28.57% higher than that of the wild type. Pearson correlation analysis showed that photosynthetic capacity was significantly and positively correlated with CaCO3 excretion. The above study not only provided enriched new germplasm of C. willmottianum, but also important research material for studying the mechanism of CaCO3 excretion by salt glands and carbon sequestration capacity of biomineralization.

Carbon Stock Dynamics in Rubber Plantations Along an Elevational Gradient in Tropical China

Carbon (C) losses due to the conversion of natural forests adversely affect the biotic and abiotic components of terrestrial ecosystems. In tropical China, rubber cultivation often extends from its traditional range to elevations of up to 1400 m. However, C stock in rubber plantations along elevation gradients is poorly understood. In this study, we investigated biomass and C stock along elevation gradients in two age groups (8- and 12-year-old) of rubber monoculture plantations in Xishuangbanna, Southwest China. The C distribution across various tree sections, ranging from aboveground biomass (AGB) to belowground biomass (BGB), including litter, big dead branches, and different soil depths were measured. A significant negative correlation was observed between AGB, BGB, litter, and total ecosystem C stocks and elevation gradients in both age groups. However, no correlation was observed between the total soil C stock and elevation gradients in 8-year-old rubber plantations, while significant decline was detected in 12-year-old rubber plantations. The highest ecosystem C stock of 197.90 Mg C ha−1 was recorded at 900 m in 8-year-old plantations; whereas, in 12-year-old rubber plantations, the highest value of 183.12 Mg C ha−1 was found at 700 m. The total ecosystem C stock decreased to their lowest level at 1000 m in both the 8-year-old and 12-year-old plantations, ranging between 113.05 Mg C ha−1 and 125.75 Mg C ha−1, respectively. Moreover, total ecosystem C stock significantly decreased from 51.55% to 8.05% and from 42.96% to 11.46% between 700 m and 1100 m, in both 8-year-old and 12-year-old plantations, respectively. Regardless of elevation gradients, the total ecosystem C stock of 12-year-old rubber plantations was 1.98% greater than that of 8-year-old rubber plantations. Biomass was the second largest contributor, while soil accounted for 82% to 90%, and the other components contributed less than 2% of the total ecosystem C stock in both age groups. These fluctuations in C stock along elevation gradients in both 8- and 12-year-old plantations suggested that rubber growth, biomass, and C stock capacity decreased above 900 m, and that age and elevation are key factors for biomass and C stock in rubber monoculture plantations.

Numerical modelling of biogeomorphological processes in salt marsh development: Do short-term vegetation dynamics influence long-term development?

Salt marshes are critical coastal ecosystems that provide numerous services. They are governed by complex biogemorphological interactions on multiple spatiotemporal scales. To simulate long-term salt marsh development in numerical models, smaller- and shorter-term vegetation processes are often neglected. This study investigates the importance of spatiotemporally and seasonally varying vegetation dynamics on decadal salt marsh development in an integrated numerical biogeomorphological model simulating a representative, idealized case of the Dutch Western Scheldt Estuary. The focus lies on the influence of seasonal vegetation dynamics, interspecific interactions between two salt marsh species, and the stabilizing effect of below-ground biomass with increasing vegetation age on critical shear stress, which results in spatially non-uniform erosion resistance of sediment and vegetation. By incorporating seasonal growth periods and varying characteristics of vegetation, we demonstrate the impact of species-specific traits on vegetation stability and morphological changes. Introducing an additional pioneer species that can establish further seaward reveals the sheltering effect and the long-term implications of this zonation for marsh development. Additionally, the influence of spatially and temporally varying below-ground biomass on sediment stability and vegetation's resistance to uprooting is significant for the biogeomorphological interactions. Comparison of the different model simulations to topographical data from the Dutch Western Scheldt Estuary shows that the model results are representing the morphological variability occurring in the field. Our findings highlight the complex biogeomorphological feedback that govern salt marsh development and show that models that neglect shorter-term seasonal and grid-scale (25 m2) spatially varying processes may overlook critical interactions that influence the lateral extent and overall morphological development of salt marshes. Therefore, this study underscores the need to integrate seasonal dynamics, species diversity, and below-ground biomass variability into biogeomorphological models to enhance predictive accuracy. This approach provides a more comprehensive understanding of the large-scale, long-term consequences of seasonal and spatiotemporally varying vegetation processes, which is essential for informing conservation and management strategies under changing climatic conditions.

Environmental impact assessment of Flora and its role in offsetting carbon along National Highway-16, India.

The rapid increase in carbon and other greenhouse gases is likely to change the regional and global temperature, and planning of these gases is needed. The present study focused on National Highway-16 of the Srikakulam district, which was upgraded from 4 to 6 lane standards to facilitate traffic. This study intended to compute the carbon sequestration and storage capacity of above and belowground biomass. This helps in the comparison and impact of the road project on flora and its carbon pool, from where future tree stock changes can be prepared. A total of 1930 plots were constructed of criss-crosses of equal size (2 × 100m). All woody trees with dbh ≥ 30cm were considered and their diameters were measured. A total of 29 tree species belonging to 13 families were identified; the quantity of macrobiotic carbon sequestered as a whole, i.e., above and below ground, was 768,890.29 tC and 199,911.48 tC, respectively. The mean sequestration rate of carbon as biomass above ground was 1.19 tC/tree, and that below ground was 0.31 tC/tree. The estimated average C-Stock per tree was 1.5 tC; however, the mean C-Stock per quadrate was 250.2 tC.

The contribution of tropical forests to climate change mitigation. Biomass estimation techniques a necessary tool in their assessment

Climate change is a global problem caused by human activities such as burning fossil fuels and deforestation. This leads to indicators of climate change like increased flooding, sea level rise, and water stress. Tropical forests play a crucial role in mitigating climate change through photosynthesis, storing large amounts of carbon in their biomass. Two methods, destructive and non-destructive, are commonly used to estimate the biomass of tropical forests. There are five components of biomass in these ecosystems, with most of it found aboveground. Belowground biomass is estimated based on aboveground biomass. About 50 % of the dry biomass in forest ecosystems is carbon. Allometric equations are used to estimate biomass and volume based on tree diameter and height. Different equations have been developed for different species and locations. Carbon stocks in forest ecosystems are present in both aboveground and belowground parts.

Reseeding increased plant biomass production and soil fertility, but not plant species diversity in degraded grasslands in China

Reseeding is a primary measure to restore degraded grasslands. Numerous studies have conducted experiments to investigate how the properties of grassland ecosystems respond to reseeding in China. However, there is a lack of summary of the results of these studies. Here, we conducted a hierarchical random-effects meta-analysis on the effects of reseeding on plant, soil, and microbial properties. We collected 19 variables, including plant biomass, species diversity and richness, soil organic carbon content, soil total and available nutrients, soil water content, soil microbial biomass and diversity, and enzyme activity, from a dataset of 1363 paired observations (degraded vs. reseeded) from 75 publications. The results showed that reseeding increased aboveground and belowground plant biomass by 70.2% and 68.0% on average, respectively. Reseeding increased soil organic carbon, phosphorus, and potassium contents, but did not affect soil nitrogen levels. Reseeding increased soil microbial nitrogen under conditions of tillage and fertilization. Reseeding age was found to have a positive correlation with species richness, while planting type, fertilization, and tillage did not have a significant impact on the species richness and diversity. Under the treatments of fertilization, non-tillage, and mix-planting, the response ratio of aboveground biomass to reseeding was positively correlated with the response ratio of species diversity to reseeding. Our results concluded that current reseeding practices can significantly improve plant biomass production and soil fertility but have minor effects on plant species diversity. These findings indicate that the preservation of biodiversity should receive greater attention from both researchers and practitioners in grassland remediation in China.

Effects of Water–Nitrogen Interaction on Sandy Soil, Physiology, and Morphology of Tall Fescue (Festuca arundinacea Schreb) Turf

The soil water and nitrogen (N) levels are the important factors affecting turfgrass growth. However, the impact of the water–N interaction on tall fescue (Festuca arundinacea Schreb) in terms of the N metabolism and plant morphology remains uncertain. Therefore, the objective of this study was to investigate the impacts of different N and water levels on the physiological and morphological responses of tall fescue. The experiment was designed with N (N0, N2, and N4 representing N application rates of 0, 2, and 4 g m–2, respectively) and irrigation [W1, W2, W3, W4, and W5 representing field water capacities (FWCs) of 90~100%, 75~85%, 60~70%, 45~55%, and 30~40%, respectively] treatments, and the relevant indexes of the soil water content and soil NH4+–N and NO3−–N levels as well as the physiology and morphology of the tall fescue were determined. The results demonstrated significant changes in the contents of soil water (SWC) and N and the physiological and morphological indexes, except for the enzymes related to N metabolism, including nitrite reductase (NiR), glutamate dehydrogenase (GDH), and glutamate synthetase (GOGAT). The water stress significantly enhanced the water and N use efficiencies (WUE and NUE), except the NUE in the W5 treatment. The N stress significantly influenced the SWC, soil NO3−–N content, and physiological and morphological indexes, excluding malondialdehyde, NiR, GOGAT, and above- (AGB) and below-ground biomass, resulting in the increased WUE and NUE. The application of a low N rate effectively alleviated the detrimental impacts of water stress on the SWC and glutamine synthetase activity. In conclusion, W2 and N2 are deemed more appropriate treatments for the low-maintenance measures of tall fescue turf. Among all the treatments, N2W2 is recommended as the optimal water–N interaction treatment due to its ability to conserve resources while still ensuring high turf quality.

Grazing exclusion promotes soil organic carbon accumulation in Tibetan grasslands with lower temperatures

BackgroundGrazing exclusion is a practical approach to restore vegetation in degraded grasslands and enhance soil organic carbon (SOC) sequestration. However, the dynamics and drivers of SOC in grasslands after grazing exclusion have not been well documented, especially in ecosystems with cold climates.MethodsHere, we established 14 paired treatments (grazing exclusion vs. free-grazing) along a 600-km transect in the northeastern zone of the Qinghai-Tibet Plateau. After six years, we analyzed vegetation biomass dynamics and measured the soil physicochemical properties and organic C concentration across three depths (0–10, 10–20, and 20–30 cm).ResultsGrazing exclusion significantly increased above- and belowground biomass (139.85% and 43.30%, respectively), pH (1.38%), total phosphorus (3.29%), nitrate nitrogen (18.03%), and ammonium nitrogen (17.81%), but significantly decreased soil bulk density (2.43%) and clay content (10.49%), particularly in 0–30 cm. Specifically, SOC concentrations positively responded to grazing exclusion (0–10 cm) in 9 of the 14 sites evaluated. The effects of grazing exclusion on SOC concentrations were significantly higher in areas with a mean annual temperature (MAT) below 0 °C compared to those in sites with a high MAT (> 0 °C). The SOC concentrations significantly correlated with the mean annual precipitation (MAP) in both treatments, but these correlations diminished with increasing soil depth. Ridge regression analysis showed that soil chemical properties (e.g., total nitrogen and phosphorus) positively influenced SOC accumulation, while MAT negatively influenced it after grazing exclusion. Path analysis further revealed that MAT indirectly regulated SOC dynamics via soil chemical properties.ConclusionsOur study highlights that grazing exclusion results in an asynchronous SOC and plant biomass accumulation and may be more beneficial for SOC sequestration in Qinghai-Tibet Plateau grasslands with lower temperatures. Also, humid climates promote SOC concentration in alpine grasslands. These results could help develop management practices and policies that promote sustainable grassland management.