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Decomposition of coarse detritus (e.g., dead organic matter larger than ~1 mm such as leaf litter or animal carcasses) in freshwater ecosystems is well described in terms of mass loss, particularly as rates that compress mass loss into one number (e.g., a first-order decay coefficient, or breakdown rate, “k”); less described are temporal changes in the elemental composition of these materials during decomposition, with important implications for elemental cycling from microbes to ecosystems. This stands in contrast with work in the terrestrial realm, where a focus on detrital elemental cycling has provided a sharper mechanistic understanding of decomposition, especially with specific processes such as immobilization and mineralization. Notably, freshwater ecologists often measure carbon (C), nitrogen (N), and phosphorus (P), and their stoichiometric ratios in decomposing coarse materials, including carcasses, wood, leaf litter, and more, but these measurements remain piecemeal. These detrital nutrients are measurements of the entire detrital–microbial complex and are integrative of numerous processes, especially nutrient immobilization and mineralization, and associated microbial growth and death. Thus, data relevant to an elemental, mechanistically focused decomposition ecology are available in freshwaters, but have not been fully applied to that purpose. We synthesized published detrital nutrient and stoichiometry measurements at a global scale, yielding 4038 observations comprising 810 decomposition time series (i.e., measurements within a defined cohort of decomposing material through time) to build a basis for understanding the temporality of elemental content in freshwater detritus. Specifically, the dataset focuses on temporally and ontogenetically (mass loss) explicit measurements of N, P, and stoichiometry (C:N, C:P, N:P). We also collected ancillary data, including detrital characteristics (e.g., species, lignin content), water physiochemistry, geographic

Soils play a major role in the global carbon cycle and are crucial to the management of climate change. Changes in plant cover derived from different agricultural practices induce variations in the quality of plant residue inputs and in the soil microbial community structure and activity, which may enhance the storage and protection of organic carbon (OC) and nitrogen (N) within aggregates. The aim of this study was to assess how differences in the chemical composition of plant residues in combination with tillage management practices affect the local microbial community activity and structure, and subsequent soil aggregation and OC and N dynamics in an organic, rainfed almond (Prunus dulcis Mill.) orchard. In the laboratory, three types of plant residue (shoots, roots, and the combination of both) coming from different species belonging to each agricultural practice (reduced tillage, reduced tillage plus green manure, reduced tillage plus organic manure, and no-tillage) were mixed with their respective soils and the CO2 released was measured over 243 days at 60% WHC and 28 °C. Water-stable aggregates (including microaggregates within macroaggregates), enzymatic activities related to carbon (dehydrogenase and ß-glucosidase) and N (urease) cycling, and the microbial biomass and community structure through phospholipid fatty acid analysis, were measured at the end of the incubation period. Our results indicate that the chemical composition of plant residues controls the microbial community response, mediating decomposition and the incorporation of OC and N in stable aggregates. Therefore, the incorporation of labile and N-rich plant residues into the soil by reduced tillage is recommended since mixing roots and shoots from green manure increased the formation of free micro-aggregates and improved OC and N stabilization in our semiarid agroecosystem. © 2021 Elsevier Ltd

The aim of this research was to study the dynamic of N in the intercropping pattern of maize and soybeans given residues of maize and soybeans and their biochar.  Information on  the use of plant residues from crop residues and biochar as amendments and sources of organic matter in different cropping patterns against nitrogen dynamics in the field is still lacking.  The experiment was arranged in a divided  plot design with five residual treatments as subplots and five cropping patterns as the main plots.  Measurement of the dynamics of N, pH and C-soil organic was carried out to study the interaction effect of the two treatments.  The results showed that residues of corn, soybeans or those containing soybeans residues and their biochar in different intercropping patterns significantly affected levels of Nitrogen, C-organic, and soil pH, where the increase in total N levels was highest in corn and soybean residues and biochar in corn intercropping and soybean (1:2), and (2:4), and for soil organic content increase to 1.93% when the plats were 15 DAS, increased to 3,22%  at 30 DAS and then decreased to 1,19% at plant age 45 DAS.  Thus, giving corn and sobean residues  and biochar to corn-soybean intercropping can increase the total N and C-organic soil levels

Temperate grassland soils store significant amounts of carbon (C). Estimating how much livestock grazing and manuring can influence grassland soil organic carbon (SOC) is key to improve greenhouse gas grassland budgets. The Rothamsted Carbon (RothC) model, although originally developed and parameterized to model the turnover of organic C in arable topsoil, has been widely used, with varied success, to estimate SOC changes in grassland under different climates, soils, and management conditions. In this paper, we hypothesise that RothC-based SOC predictions in managed grasslands under temperate moist climatic conditions can be improved by incorporating small modifications to the model based on existing field data from diverse experimental locations in Europe. For this, we described and evaluated changes at the level of: (1) the soil water function of RothC, (2) entry pools accounting for the degradability of the exogenous organic matter (EOM) applied (e.g., ruminant excreta), (3) the month-on-month change in the quality of C inputs coming from plant residues (i.e above-, below-ground plant residue and rhizodeposits), and (4) the livestock trampling effect (i.e., poaching damage) as a common problem in areas with higher annual precipitation. In order to evaluate the potential utility of these changes, we performed a simple sensitivity analysis and tested the model predictions against averaged data from four grassland experiments in Europe. Our evaluation showed that the default model's performance was 78% and whereas some of the modifications seemed to improve RothC SOC predictions (model performance of 95% and 86% for soil water function and plant residues, respectively), others did not lead to any/or almost any improvement (model performance of 80 and 46% for the change in the C input quality and livestock trampling, respectively). We concluded that, whereas adding more complexity to the RothC model by adding the livestock trampling would actually not improve the mod

The ever-increasing demand for green and clean energy urge the development of cheap and efficient electrode materials for supercapacitors (SCs). In this context, several naturally abundant bio-wastes have been explored to develop porous carbons for SCs due to their easy availability, high performances, and simple processing methods. Although various BDCs are utilized for SC, the relation between the bio-waste precursor and resultant carbon materials are not very well understood. Here, we highlight how the different bio-waste precursors affect the surface characteristics of the carbon nanostructures and outlined their subsequent effect on electrochemical performances. Moreover, the surface modification of carbon materials using pre-processing, carbonization and activation methods is provided. The supercapacitive properties of activated carbons (AC) with their unique surface features derived from the different feedstock are systematically summarized. Finally, the challenges and future directions for the development of AC from bio-waste are discussed. Overall, this review provides a guide to understand how best to refine and carbonize this biomass to achieve optimum supercapacitive performance. © 2021

The soil microbiota, a key component of natural ecosystems, is considered as a factor determining the stability of meadow communities. The diversity and abundance of the main ecologically significant groups of microorganisms in meadow soils have been studied along a gradient of long-term soil pollution with heavy metals in the Middle Urals. The results provide evidence for stability of the microbial assemblage formed in these soils. It has been found that the functional activity of certain physiological groups of microorganisms (nitrogen-fixing, denitrifying, and cellulolytic bacteria) and the respiratory activity of microbial communities are stimulated under conditions of heavy-metal soil pollution. Probable effects of the observed changes on mineralization of plant remains in meadow communities are discussed. © 2014 Pleiades Publishing, Ltd., 13 04 96056, ACKNOWLEDGMENTS This study was supported by the Russian Founda tion for Basic Research (project no. 13 04 96056 r_ural_a), Scientific School Support Program (project no. NSh 5325.2012.4), and the Presidium of the Ural Branch of the Russian Academy of Sciences (project no. 12 I 4 2051).

Improved management of agricultural soils has potential for sequestering carbon (C) and reducing the accumulation of atmospheric carbon dioxide. Development of management practices to increase C sequestration is dependent on improved understanding of soil processes influencing long-term storage of C. A field study was conducted to compare surface C source quality and above- vs. belowground addition of annual or perennial plant biomass effects on particulate organic matter (POM), total labile C (TLC), and total organic C (TOC). Since microaggregate stabilization within macroaggregates is the main mechanism for sequestering C, aggregate size distribution, expressed as mean weight diameter (MWD), and wet aggregate stability (WAS) was also measured. After 5 years, POM decreased in plots receiving surface application of readily available substrate (sucrose and alfalfa pellets) and the bare surface control. Plots receiving plant additions [wood chips, growing wheat (Triticum aestivum L.) crop, growing switchgrass (Panicum virgatum L.) crop, and fallow receiving either wheat or switchgrass residue] exhibited higher TLC and TOC content. Plots receiving plant residue maintained MWD, and those supporting live plants exhibited increasing WAS. Surface plant residue protected the soil against raindrop impact and reduced the intensity of wetting and drying cycles allowing the development of larger more stable aggregates resulting in C accrual.

We have been assessing the activity level of cellulase in wetland sediments to clarify the significance of cellulase for the turnover of plant cellulose in wetlands. In this study, we investigated the cellulose degrading function of sediment in wetlands to clarify the biochemical breakdown mechanism of cellulose. Specifically, we measured cellulase activities of sediments collected from wetlands of the Chikugo River (Fukuoka Prefecture), Midori River (Kumamoto Prefecture), Hamado River (Kumamoto Prefecture), Yodo River (Osaka Prefecture), and Tanaka River (Mie Prefecture). The results revealed that the activity levels differed significantly among rivers. Additionally, the cellulase activities of the sediment were not completely suppressed in the presence of chloramphenicol. These findings suggested that a portion of the cellulase activities were derived from cellulases binding to the components of sediments. Actually, sediments also showed the ability to bind fungal cellulase. Comparison of the binding ability of clay and plant residues, the main components of sediments, revealed that plant residues had significantly higher abilities to bind cellulase. This finding was supported by the fact that there was a strong correlation between the organic matter content in the sediment and the cellulase-binding ability (R = 0.66). Results of this study show that sediment complexes harboring cellulases might function as a bioreactor to degrade cellulose in wetlands.

Three studies were undertaken from 2006 to 2007 to examine litter (dead plant material) in southwestern Manitoba pastures. First, the relationship between litter and soil microclimate was tested across five pasture sites. The amount of litter biomass was not strongly related to soil moisture, though near-surface soil temperatures were reduced when litter was present. Second, the effect of four simulated grazing strategies on the litter layer was measured in six pastures. It was found that after three years of simulated grazing, litter was present in largest quantities in the least-frequently grazed treatments. Finally, a field survey was conducted assessing the quantity of litter present in native pastures across Manitoba. Litter was quite variable and averaged 1902 kg/ha over two years. This research confirmed the value of litter as an indicator of sustainable pasture management, though it remains unclear whether litter is important to pastures from the perspective of soil microclimate.