Aboveground Plant Biomass Research Articles

Grassland management strategies influence soil C, N, and P sequestration through shifting plant community composition in a semi-arid grasslands of northern China

Current studies regarding the effects of grassland management strategies on the soil nutrient cycle have mostly focused on soil organic carbon (SOC). Less is known about the responses of SOC, total nitrogen (TN), and total phosphorous (TP) stocks to grassland management strategies at different soil depths. We therefore quantified vertical variations in SOC, TN, and TP stocks as well as controlling factors under three grassland management strategies (i.e., enclosure control, grazing twice a year, grazing combined with mowing) in 2014 and 2017 in a semi-arid grassland of northern China. We found that grazing twice a year and grazing combined with mowing led to an increase in plant production as well as soil C and N sequestration during 2014 to 2017. Changes in plant aboveground biomass (AGB), belowground biomass (BGB), and root-to-shoot ratio (R:S) all exerted significant positive effects on changes in soil C and N sequestration in the surface soil layer (0–30 cm), while changes in AGB and plant community composition played a more important role in mediating soil C, N, and P sequestration in response to grassland management strategies in the subsoil layer (30–100 cm). Specifically, grassland management strategies influence soil C, N, and P sequestration capacity by altering plant community composition. The results of this study provide new insights into the response mechanisms of plants and soils to grassland management practices and offer a range of new possible strategies that might be applied to the effective management of semi-arid grasslands.

Elevation explains variation in soil microbial diversity and community composition under experimental warming and fertilization treatments in mountain meadows

Climate warming and atmospheric nitrogen deposition threaten plant biodiversity in mountain ecosystems; however, their influences on soil microbial diversity and community composition remain poorly understood. We conducted randomized block factorial experiments in three mountain meadows of different elevations on Yulong Snow Mountain, China. These include open-top chambers and urea fertilization to simulate climate warming and nitrogen deposition, respectively. Using Next-generation sequencing (NGS) technology, we measured soil microbial diversity and community composition for archaea, bacteria, and fungi. In addition, we measured plant diversity, plant aboveground biomass, soil chemical characteristics, air temperature, and rainfall as quantitative predictors. We determined the most parsimonious relationships with soil microbial diversity and community composition for each predictor based on generalized linear mixed-effect models and distance-based redundancy analyses, respectively. Elevation explained the majority of the variation associated with microbial diversity under short-term warming and fertilization. Microbial diversity decreased with increasing elevation, and the tendency was strongest for bacteria. Fertilization decreased bacterial diversity at the highest elevation but increased fungal diversity across the elevational gradient; microbial community composition was weakly affected by elevation. Climatic factors, especially air temperature, were the most important determinants of soil microbial diversity and composition. Taken together, the results presented here contribute to our understanding of how future global climate change may impact the belowground diversity of mountain ecosystems.

Plant Biomass Production in Constructed Wetlands Treating Swine Wastewater in Tropical Climates

The production of both aboveground and belowground plant biomass in constructed wetlands (CW) is a poorly understood topic, although vegetation plays an important role in the process of pollutant removal from wastewater. The objective of this study was to evaluate the aboveground and belowground biomass production of Typha latifolia and Canna hybrids in a large-scale constructed wetland treating swine wastewater in tropical climates. Parameters, such as temperature, DO, pH, COD, TSS, TN, TP, and TC, as well as destructive and non-destructive biomass, were evaluated. It was found that, despite the high concentrations of pollutants, the vegetation adapted easily and also grew healthily despite being exposed to high concentrations of pollutants from swine water. Although Typha latifolia (426 plants) produced fewer plants than Canna hybrids (582 plants), the higher biomass of the Typha latifolia species was slightly higher than that of Canna hybrids by 5%. On the other hand, the proximity of the water inlet to the system decreased the capacity for the development of a greater number of seedlings. As for the elimination of pollutants, after treatment in the constructed wetland, COD: 83.6 ± 16.9%; TSS: 82.2 ± 17.7%; TN: 94.4 ± 15.8%; TP: 82.4 ± 23.2%; and TC: 94.4 ± 4.4% were significantly reduced. These results show that wetlands constructed as tertiary systems for the treatment of swine wastewater produce a large amount of plant biomass that significantly helps to reduce the concentrations of pollutants present in this type of water in tropical areas. The use of these plants is recommended in future wetland designs to treat swine wastewater.

Plant functional types drive differential responses of grassland ecosystem functions along a precipitation gradient

Climatic variations can profoundly impact the functioning of grassland ecosystem, and understanding the drivers is critical for predicting ecosystem function under future climate. However, whether and how the responses of multiple grassland ecosystem functions to precipitation across spatial scales are controlled by the differential responses of the dominant plant functional types (PFT) remains unclear, mainly due to the scarcity of regional observational data. Here, we examined grassland ecosystem functions (aboveground plant biomass, belowground plant biomass, soil organic carbon, and total nitrogen) with different dominant plant functional types across 100 sites of four precipitation gradients in the Northeastern Qinghai-Tibetan Plateau by the moisture index. Across the broad precipitation gradient, higher mean annual precipitation significantly increased the plant species diversity and grassland ecosystem functions (aboveground plant biomass, soil organic C, and total N). From arid zone to humid zone, the above- and below-ground plant biomass allocation shifted to aboveground, and the trade-off between above- and below-ground plant biomass was the largest in semi-humid zone (0.13). Moreover, above- and below-ground plant biomass in arid, semi-arid, and semi-humid zones were driven by the grass-dominated communities (52%∼91%), while the humid zone was driven by the sedge- and forb- dominated communities (36%∼46%). The results of structural equational models further showed that the effects of precipitation on the ecosystem functions (soil organic carbon and total nitrogen) were mediated by either aboveground plant biomass (mainly in sedge-dominated communities) or species diversity (forb- and grass-dominated communities). These findings reveal that the asynchrony responses of different PFT-dominated communities to precipitation are altering grassland ecosystem functions, which provides the novel insight that plant functional group is particularly important for predicting ecosystem functioning under future climate conditions.

Potato (Solanum tuberosum L.) Growth in Response to Foliar Silicon Application

As silicon induces abiotic stress tolerance in crop plants, it was hypothesized that foliar silicon application could improve potato growth in an early crop culture. The effect of dosage (0.25 dm3·ha−1 or 0.50 dm3·ha−1) and time (the leaf development stage, BBCH 14–16, tuber initiation stage, BBCH 40–41, or both the leaf development stage and tuber initiation stage) of application of the silicon-based biostimulant Optysil (200 g SiO2 and 24 g Fe in 1 dm3) on potato growth was investigated. Optysil caused an increase in plant height and above-ground plant biomass, enlarged leaf area and decreased leaf weight ratio (LWR), and, as a result, increased tuber number and tuber weight per plant. The effect of Optysil depended on a water deficit during potato growth. The average tuber weight per plant in the cultivation treated with Optysil was higher by 23% under periodic water deficits during potato growth, and by 13% under drought conditions, than in the cultivation without the biostimulant. Dosage of Optysil had a significant effect on above-ground plant biomass and leaf area in the warm and arid growing season. Under drought stress, Optysil at 0.50 dm3·ha−1 stimulated potato growth more than at 0.25 dm3·ha−1. Under periodic water deficits during potato growth, the time of Optysil application affected potato growth more than the biostimulant dosage. The plants produced greater above-ground biomass and had a larger leaf area with two Optysil applications; one in the initial plant growth period (BBCH 14–16), and a repeated treatment in the tuber initiation stage (BBCH 40–41). The tuber weight per plant was positively correlated with the plant height, above-ground plant biomass, leaf area, and LWR.

Soil carbon stocks in temperate grasslands differ strongly across sites but are insensitive to decade-long fertilization.

Enhancing soil carbon (C) storage has the potential to offset human-caused increases in atmospheric CO2 . Rising CO2 has occurred concurrently with increasing supply rates of biologically limiting nutrients such as nitrogen (N) and phosphorus (P). However, it is unclear how increased supplies of N and P will alter soil C sequestration, particularly in grasslands, which make up nearly a third of non-agricultural land worldwide. Here, we leverage a globally distributed nutrient addition experiment (the Nutrient Network) to examine how a decade of N and P fertilization (alone and in combination) influenced soil C and N stocks at nine grassland sites spanning the continental United States. We measured changes in bulk soil C and N stocks and in three soil C fractions (light and heavy particulate organic matter, and mineral-associated organic matter fractions). Nutrient amendment had variable effects on soil C and N pools that ranged from strongly positive to strongly negative, while soil C and N pool sizes varied by more than an order of magnitude across sites. Piecewise SEM clarified that small increases in plant C inputs with fertilization did not translate to greater soil C storage. Nevertheless, peak season aboveground plant biomass (but not root biomass or production) was strongly positively related to soil C storage at seven of the nine sites, and across all nine sites, soil C covaried with moisture index and soil mineralogy, regardless of fertilization. Overall, we show that site factors such as moisture index, plant productivity, soil texture, and mineralogy were key predictors of cross-site soil C, while nutrient amendment had weaker and site-specific effects on C sequestration. This suggests that prioritizing the protection of highly productive temperate grasslands is critical for reducing future greenhouse gas losses arising from land use change.

Grazing influences biomass production and protein content of alpine meadows

Alpine grasslands are essential for carbon sequestration and food supply for domestic and wild herbivores inhabiting mountainous areas worldwide. These biomes, however, are alternatively threatened by the abandonment of agricultural and livestock practices leading to a fast-growing shrubification process while other mountain grasslands are suffering from the impacts of overgrazing. The functioning of alpine meadow ecosystems is primarily driven by climatic conditions, land-use legacies and grazing. However, although it is critically important, the role of large herbivores on the aboveground biomass and protein content of palatable plants is poorly understood for most alpine meadows. In this work, we explore the effects of grazing on grassland vegetation at two different spatial and temporal scales in the Eastern Pyrenees, Spain. Remote sensing was used to assess the effect of high and moderate grazing (HG and MG respectively) on grass biomass using the leaf area index (LAI) at the meso-scale (patches between 2.3 and 38.7 ha). We also explored the impact of null (NG), overgrazing (MO, mimicked overgrazing) and high (HG) grazing intensities at local scale setting eighteen 1 m2 exclusion boxes in six meadows (three boxes each) commonly used by domestic and wild ungulates. Historical satellite data showed that LAI values are greater in high than in low grazed areas (HG, mean = 0.66, LG, mean = 0.55). Along the same lines, high and moderate grazing pressures improved biomass production at the local-scale (HG, mean = 590.3 g/m2, MO, mean = 389.3 g/m2 and NG, mean = 110.8 g/m2). Crude protein content reached higher values under MO pressure than under HG pressure. Our results confirm that grazing intensity exerts significant changes on the above-ground biomass production and the protein content of plants consumed by domestic (cattle and horses) and wild ungulates (Southern Chamois, Rupicapra pyrenaica). We can conclude that ungulates sustain biomass and nutritive values of grass exerting a negligible effect on biomass and protein content of woody vegetation. Our results will inform management guidelines to support profitable grazing activities and promote conservation of the open landscapes in the alpine ecosystems under the current global change scenario.

Long-term warming effects on the microbiome and nifH gene abundance of a common moss species in sub-Arctic tundra.

Bacterial communities form the basis of biogeochemical processes and determine plant growth and health. Mosses harbour diverse bacterial communities that are involved in nitrogen fixation and carbon cycling. Global climate change is causing changes in aboveground plant biomass and shifting species composition in the Arctic, but little is known about the response of moss microbiomes in these environments. Here, we studied the total and potentially active bacterial communities associated with Racomitrium lanuginosum in response to a 20-yr in situ warming in an Icelandic heathland. We evaluated the effect of warming and warming-induced shrub expansion on the moss bacterial community composition and diversity, and nifH gene abundance. Warming changed both the total and the potentially active bacterial community structure, while litter abundance only affected the total bacterial community structure. The abundance of nifH genes was negatively affected by litter abundance. We also found shifts in the potentially nitrogen-fixing community, with Nostoc decreasing and noncyanobacterial diazotrophs increasing in relative abundance. Our data suggest that the moss microbial community and potentially nitrogen fixing taxa will be sensitive to future warming, partly via changes in litter and shrub abundance.

Elevated CO2 affects the rhizosphere microbial community and the growth of two invader plant species differently in semiarid Mediterranean soils

AbstractThe rise in atmospheric CO2 levels is foreseen to enhance the growth of exotic invasive plants and potentially alter the rhizosphere microbial community, which in turn could enhance the risk of colonization by such invaders. This response could be determined by the plant type and the features of invaded soil. The goal of this investigation was to compare the effects of elevated CO2 on the rhizosphere bacterial and fungal communities of two invaders with distinct degrees of invasiveness, Nicotiana glauca and Mirabilis jalapa, by growing the plants in five different semiarid soils at ambient (410 ppm) or elevated (760 ppm) CO2. The changes in soil physicochemical, biochemical, and biological features mediated by the invaders were also evaluated. The effect of CO2 supply on shoot dry biomass was only significant for N. glauca, the shoot and root biomass of plants grown under elevated CO2 being approximately 53% and 14% greater, respectively, than those of the plants grown under ambient CO2. Elevated CO2 only promoted shifts in the rhizosphere bacterial community composition and enhanced the bacterial functional potential related to nucleoside and nucleotide biosynthesis and N‐cycling in N. glauca. Among the bacterial indicator species, the genera Sphingomonas, Stenotrophobacter, and Gaiella were more abundant in the rhizosphere of N. glauca plants grown under elevated CO2. This study demonstrates that the responses of aboveground and belowground biomass of invasive plants to CO2 enrichment, as well as those of the composition and functioning of soil microbial communities, are dependent on their degree of invasiveness.

Growth responses and differential expression of VrDREB2A gene at different growth stages of mungbean (Vigna radiata L. Wilczek) under drought stress.

The online version contains supplementary material available at 10.1007/s12298-021-01089-w.

Responses of ecosystem respiration, methane uptake and nitrous oxide emission to drought in a temperate desert steppe

AimsDrought significantly impacts ecosystem structure and function, especially the transformation rates of soil carbon and nitrogen. This study explores how drought affects ecosystem respiration (Re), methane (CH4) uptake and nitrous oxide (N2O) emissions in temperate desert steppes and the underlying mechanisms.MethodsAn in-situ experiment was conducted in the Inner Mongolia desert steppe in northern China to study the effect of drought on Re, CH4 and N2O fluxes. Structural equation modeling (SEM) was used to establish the relationship between Re, CH4 uptake and N2O emissions and plant functional traits and environmental factors.ResultsEcosystem respiration and CH4 uptake were both significantly reduced by chronic drought (66 % precipitation reduction from 1 May to 31 August) but not by pulse drought (100 % precipitation reduction in June and July). In contrast, no significant impact on N2O emissions was observed under chronic or pulse drought. There were no significant direct effects of soil moisture on Re, CH4 uptake or N2O emissions. However, soil moisture had an important indirect effect on Re, CH4 uptake and N2O emissions, mainly through its influence on plant functional traits, plant above-ground biomass and soil nutrients. Plant biomass and soil temperature were the key indicators of Re, and plant leaf nitrogen content was the key plant trait associated with N2O emissions. In contrast, plant specific leaf area and biomass were the key traits associated with CH4 uptake.ConclusionsOverall, Re and CH4 uptake were reduced by chronic drought in this desert steppe, but there was no significant effect on N2O emissions. Ecosystem respiration, CH4 uptake and N2O emissions were associated with plant functional traits. This provides new insight for the understanding of soil carbon and nitrogen dynamics in desert steppe systems under drought conditions and an important theoretical basis for the revision of model parameters.

Biochar Effects on Soil–Plant Properties after Six Month Adaptation in Soil

ABSTRACT Biochar (BCH) is one of the most promising amendments to improve soil quality and store carbon in soils. Vast majority of the studies utilized freshly produced materials and assess BCH effects immediately after soil amendment. The aim of this study was to investigate the influence of biochars aged six months with two soil types on soil physicochemical and biological properties along with plant growth. Soils from a protection zone of water sources and from an agricultural area were mixed with three different types of BCH. After six months of aging, lettuce (Lactuca sativa var. capitata) plants were grown on these soils in greenhouse. Plant aboveground and root biomass, soil physicochemical properties [pH, cation exchange capacity (CEC), total nitrogen (TN), soil organic carbon (SOC), and total phosphorus (TP)], and biological activities [fluorescein diacetate activity (FDA) and urease activities, soil respiration, and` humic and nitrogen index] were determined. Studied BCHs had slight influence on soil physicochemical parameters. pH was significantly increased by all BCH amendments: in Luvisol by 12.7% and in Fluvisol by 11.25% (by 1.1 times). SOC was augmented in both soil types with the addition of the third BCH type that corresponded to the initial BCH input. BCH aging in soil had no influence on CEC, TN, TP and soil microbial activities (FDA, urease, and soil respiration). Moreover, two BCHs did not influence plant growth, whereas the third BCH type had a negative impact, decreasing lettuce development by 62% in Luvisol and by 41% in Fluvisol relative to untreated control soils.

Spatial patterns of aboveground phytogenic Si stocks in a grass-dominated catchment – results from UAS-based high-resolution remote sensing

Abstract. Various studies have been performed to quantify silicon (Si) stocks in plant biomass and related Si fluxes in terrestrial biogeosystems. Most studies are deliberately designed on the plot scale to ensure low heterogeneity in soils and plant composition, hence similar environmental conditions. Due to the immanent spatial soil variability, the transferability of results to larger areas, such as catchments, is therefore limited. However, the emergence of new technical features and increasing knowledge on details in Si cycling lead to a more complex picture at landscape and catchment scales. Dynamic and static soil properties change along the soil continuum and might influence not only the species composition of natural vegetation but also its biomass distribution and related Si stocks. Maximum likelihood (ML) classification was applied to multispectral imagery captured by an unmanned aerial system (UAS) aiming at the identification of land cover classes (LCCs). Subsequently, the normalized difference vegetation index (NDVI) and ground-based measurements of biomass were used to quantify aboveground Si stocks in two Si-accumulating plants (Calamagrostis epigejos and Phragmites australis) in a heterogeneous catchment and related corresponding spatial patterns of these stocks to soil properties. We found aboveground Si stocks of C. epigejos and P. australis to be surprisingly high (maxima of Si stocks reach values up to 98 g Si m−2), i.e. comparable to or markedly exceeding reported values for the Si storage in aboveground vegetation of various terrestrial ecosystems. We further found spatial patterns of plant aboveground Si stocks to reflect spatial heterogeneities in soil properties. From our results, we concluded that (i) aboveground biomass of plants seems to be the main factor of corresponding phytogenic Si stock quantities, and (ii) a detection of biomass heterogeneities via UAS-based remote sensing represents a promising tool for the quantification of lifelike phytogenic Si pools at landscape scales.

Pea-based cover crop mixtures have greater plant belowground biomass, but lower plant aboveground biomass than a pure stand of pea

In eastern Canada, organic grain producers have a rising interest in using cover crop mixtures instead of pure stands to maximize ecosystem services. Yield stability and belowground biomass of cover crop mixtures have however received limited attention in the scientific literature, although they do affect ecosystem services. The aims of this study were to evaluate the aboveground and belowground biomass and yield stability of pea-based cover crop mixtures, and to assess species-specific contributions to aboveground biomass. In a field experiment conducted at three site-years in Quebec, Canada, a pure stand of field pea (Pisum sativum L.) and cover crop mixtures of 2, 6, and 12 species, all including field pea, were compared to a weedy control (without cover crop). The mixtures were seeded according to a substitutive unbalanced design. The proportion of field pea ranged from 45% to 93% of the aboveground plant biomass within all mixtures. Among all site-years, pure stand of field pea provided the highest aboveground biomass (2636 kg ha−1), followed by the 2-species mixture (2320 kg ha−1) and both multi-species cover crop mixtures (mean of 1849 kg ha−1). Aboveground biomass was inversely correlated to cover crop diversity (Pearson coefficient of −0.73), and inversely correlated to weed biomass (Pearson coefficient of −0.54). Pure stand of field pea had the lowest belowground biomass and stability (693 kg ha−1, CV of 28%) when compared to mixtures (886 kg ha−1, CV of 14% on average). This study confirms that the value of pea-based mixtures, compared to a pure stand of field pea, lies mainly below the soil surface rather than above it. This could likely enhance many soil-related ecosystem services.

Non-destructive aboveground biomass estimation of Leymus chinensis individual across large scale

Monitoring how plant biomass changes with environmental conditions is critical for evaluating ecosystem carbon storage and understanding the underlying mechanisms of carbon dynamics. Usually destructive methods require a lot of time and cost. And the non-destructive methods to repeatedly estimate the biomass of herbaceous plants across large scale environmental conditions are still limited. Leymus chinensis, as an important constructive species, constitutes a unique community type in the eastern Eurasian steppe across the semi-humid, semi-arid and arid areas in the middle temperate and warm temperate zones. Therefore, it is necessary to analyze the driving factors and establish a unified estimation equation of the aboveground biomass (AGB) of L. chinensis across large scale. In this study, for the first time, we combined climatic factors and plant characteristics to analyze the individual AGB of L. chinensis in northern China, and established a non-destructive prediction model that can accurately quantify the AGB of L. chinensis across large scale in China. 33 sites across different climate conditions with L. chinensis as the constructive species in China were sampled to measure plant traits of L. chinensis individual, including leaf thickness (LT), stem diameter (SD), stem length (SL), plant height (PH), etc. We found that plant traits (PH,SD) were the main factors driving the AGB of L. chinensis individuals, and climate factors mainly affected AGB of L. chinensis individuals indirectly by affecting plant traits. Then, we established the AGB estimation equation of L. chinensis individuals across large scale for the first time. The equation was: AGB = −0.638 + 0.405*SD + 0.017*PH, which had a high predictive ability. The result is not only helpful to quickly and conveniently measure the AGB of L. chinensis individuals in non-destructive experiments, but also important to evaluate the productivity and carbon storage of L. chinensis community across large scale. At the same time, it also laid the foundation for the subsequent non-destructive estimation of the aboveground biomass of individual plants.

Filling gaps in models simulating carbon storage in agricultural soils: the role of cereal stubbles

Carbon (C) input is a prerequisite for the formation of soil organic matter and thus for soil organic C (SOC) sequestration. Here we used the C-TOOL model to simulate SOC changes in a long-term field experiment (1932–2020) at Askov, Denmark, which involved four different levels of nutrients added in mineral fertilizer (0, 0.5, 1, 1.5 NPK) and a four-crop rotation. The C input into soils consists of belowground and aboveground plant biomass and was estimated using allometric functions. The simulation showed that modelled SOC based on standard allometric functions of C input from crop residues did not adequately matched measured SOC contents. However, applying modified allometric functions based on current and the previously measured results for aboveground and belowground C inputs in winter wheat and grass clover in rotations provided much better match between simulated and measured SOC contents for fertilized treatments at normal and high level of fertilization. This improved indicators of C-TOOL model performance (e.g. yielding RMSE of 2.24 t C ha−1 and model efficiency of 0.73 in 1.5 NPK treatment). The results highlight that standard allometric functions greatly overestimates the amount of C in winter wheat stubble left after harvest in treatments dressed with NPK compared with modified functions. The results also highlight further needs for improvement of allometric functions used in simulation models for C-accounting in agroecosystems.

Precipitation changes regulate the annual methane uptake in a temperate desert steppe

Desert soils are an important sink of atmospheric methane (CH4) and regulate the global CH4 budget. However, it is still unclear how CH4 fluxes respond to precipitation changes in desert-steppe soils. Therefore, a two-year in situ control experiment was conducted to investigate the effect of precipitation changes on CH4 uptake in desert steppe of Inner Mongolia in northwest China and its driving mechanism. The result showed that this desert steppe was an important sink of CH4, with an annual uptake of 2.93 (2.64–3.22) kg C ha−1. It was found that CH4 uptake was reduced significantly for decreasing precipitation, especially in spring and summer. In contrast, an increasing trend of CH4 uptake was observed for increasing precipitation, although it was not statistically significant. Further analyses found that CH4 uptake was more sensitive to decreasing precipitation than increasing precipitation. This may be mainly due to the fact that only moderate water-filled pore space (WFPS) induced by precipitation promoted CH4 uptake, while too-high (>32%) or too-low WFPS inhibited its uptake. A structural equation model showed that the copy number of the pmoA functional gene was the most important factor affecting CH4 uptake. In contrast, soil moisture had a very important indirect effect on CH4 uptake, mainly through significantly affected soil porosity, the above-ground plant biomass and NO3−-N content, further affected CH4 uptake. Overall, CH4 sinks in desert steppe was still mainly controlled by methane-oxidizing bacteria containing the key functional gene pmoA and WFPS. Therefore, precipitation plays an important role in regulating the intensity of CH4 sinks in desert steppe, while it is worth noting that too-little precipitation will significantly weaken CH4 sinks.

Effects of Leaf Loss by Artificial Defoliation on the Growth of Different Poplar and Willow Varieties

The cultivation of fast-growing tree species in short rotation coppices has gained popularity in Germany in recent years. The resilience of these coppices to phyllophagous pest organisms is crucial for their profitable management, since the loss of a single annual increment can lead to uncompensable economic losses. To study the effects of leaf loss on the growth of poplar and willow varieties that are frequently cultivated under local conditions, three sample short rotation coppices including five poplar (Populus spp.) and three willow (Salix spp.) varieties were established in a randomized block design with four artificial defoliation variants and, on one site, with three different variants regarding the number of defoliation treatments. After up to three defoliation treatments within two growing seasons, the results show negative effects of leaf loss on the height growth and the fresh weight of the aboveground biomass of plants. Our data also suggests a lasting effect of defoliation on plant growth and re-growth after the end of the treatment. In general, defoliation had a greater impact on the growth of poplars than on willows. We conclude that even minor leaf loss can have an impact on plant growth but that the actual effects of defoliation clearly depend on the site, tree species, and variety as well as the extent and number of defoliations, which determine the ability of plants for compensatory growth.

Impacts of 21-year field warming on soil erodibility in the Qinghai-Tibetan Plateau, China

Terrestrial ecosystems are significantly impacted by global warming. To determine the effects of long-term warming on soil structure and erodibility in the Qinghai-Tibetan Plateau (China), a 21-year field warming experiment was conducted, where the soil response to temperature changes was investigated for two vegetation types (shrubland and grassland). The measured parameters included the fractal dimension (Dv) of aggregates, mean weight diameter (MWD), geometric mean diameter (GMD), multifractal dimensions of particle size distribution [capacity dimension (D0), information dimension (D1), information dimension/capacity dimension ratio (D1/D0), and correlation dimension (D2)], and soil erodibility value (K). The results show that warming significantly increases the erodibility of the topsoil (0–2 cm). Among them, the larger particles (0.2–2 mm aggregates, sand) decreased, the K factor, Dv, and multifractal dimension (D0) increased, and the MWD and GMD of the soil aggregates decreased. Long-term warming affected the amounts of soil organic carbon, total nitrogen, and total phosphorus. Furthermore, warming weakened microbial activity and led to a reduction in the aboveground biomass of plants. With increasing soil depth, the effect of warming on the erodibility of underlying soil (2–12 cm) gradually weakened. Warming exhibited different effects on the erodibility of the shrubland and grassland because of their different soil aggregates and particle size distributions. These results confirm that long-term warming has obvious soil layering effects on different soil depths. Soil properties, plants, and microorganisms respond to warming and have direct or indirect effects on soil erodibility. The results of this study provide important insights into changes in soil structure and erodibility at high altitudes, especially under global warming.

Corrigendum to: Ecosystem dynamics of crop–pasture rotations in a fifty‐year field experiment in southern South America: Century model and field results

Soil Science Society of America JournalVolume 85, Issue 5 p. 1866-1866 CORRIGENDUMFree Access Corrigendum to: Ecosystem dynamics of crop–pasture rotations in a fifty-year field experiment in southern South America: Century model and field results This article corrects the following: Ecosystem dynamics of crop–pasture rotations in a fifty-year field experiment in southern South America: Century model and field results Walter E. Baethgen, William J. Parton, Valentina Rubio, Robin H. Kelly, Susan M. Lutz, Volume 85Issue 2Soil Science Society of America Journal pages: 423-437 First Published online: March 24, 2021 First published: 28 September 2021 https://doi.org/10.1002/saj2.20316AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL In the original publication (Baethgen et al., 2021), Table 1 contains incorrect data. A corrected version of the table is presented below. The authors apologize for this error. TABLE 1. Century model simulation for 100 yr in CS2 and CS5, for five scenarios: (a) using a sequence with 3 yr of pastures followed by 3 yr of annual crops (C3P3); (b) using a sequence of 6 yr of crops and 3 yr of pastures (C6P3); (c) using a sequence of 9 yr of crops and 3 yr of pastures (C9P3); (d) using a sequence of 4 yr of crops including cover crops (CC); and (e) using a sequence of only annual crops (CONT—no pastures and no cover crops). Results are shown for the average grain yields during grain producing years, total grain production during a 100-yr time period, total C inputs from aboveground plant biomass during a 100-yr time period, and total C inputs from belowground biomass during the 100-yr time period Avg. grain yield Total grain production Total C input abovegrounda Total C input belowgroundb Scenario g C m−2 yr−1 g C m−2 in 100 yr CS2 (a) 175 12,655 20,558 12,613 CS2 (b) 142 13,071 19,441 11,178 CS2 (c) 136 13,663 19,643 10,907 CS2 (d) 130 15,486 17,823 9,280 CS2 (e) 96 11,975 15,647 8,221 CS5 (a) 196 14,210 22,426 14,030 CS5 (b) 161 14,757 21,704 12,378 CS5 (c) 144 14,368 20,567 11,434 CS5 (d) 140 16,644 19,365 10,084 CS5 (e) 100 12,518 16,480 8,631 a Crop stover + pasture + cover crops (i.e., all biomass that remained on soil) in 100 yr. b Total root biomass produced in 100 yr. REFERENCE Baethgen, W. E., Parton, W. J., Rubio, V., Kelly, R. H., & Lutz, S. M. (2021). Ecosystem dynamics of crop–pasture rotations in a fifty-year field experiment in southern South America: Century model and field results. Soil Science Society of America Journal, 2021, (85), 423– 437. https://doi.org/10.1002/saj2.20204 Volume85, Issue5September/October 2021Pages 1866-1866 ReferencesRelatedInformation