Dirt Research Articles

Effects of short-term nitrogen addition on the recovery of alpine grassland in the Tianshan Mountains of Xinjiang, China.

The restoration of alpine grasslands has garnered significant attention across various sectors. Historically, natural restoration has been the primary approach for grassland recovery, characterized by its prolonged duration. To expedite the recovery of degraded grasslands, it is essential to identify the limiting factors of restoration, enabling efficient and rapid recovery. Appropriate nitrogen (N) addition levels have been considered a potential strategy to enhance the recovery of grassland ecosystems and augment their ecological benefits. However, the effectiveness of N addition in alpine grassland restoration remains debated. This study investigated the impact of five N addition levels (CK: control [0 g/m2]; LN: low N [5 g/m2]; MN: medium N [10 g/m2]; HN: high N [15 g/m2]; SN: severe N [20 g/m2]) and two experimental approaches (N addition once per year [NPY] and three times per year [NTY] at the same dosages) on plant and soil properties and the maximum restoration capacity of alpine meadows. Our findings reveal three key insights: The level of N addition was the primary factor influencing aboveground plant biomass and coverage. Plant diversity decreased under the NTY regime and increased with NPY in the Bayinbruck grassland. N addition significantly altered soil properties, including pH, salinity, soil organic carbon (SOC), soil-available phosphorus (AP), and soil total phosphorus (TP). Notably, soil TP, total nitrogen (TN), and AP substantially impacted plant community structure and diversity. Based on structural equation model (SEM) and analysis of variance (ANOVA), optimal grassland restoration was achieved with the HN (15 g/m2) treatment under NPY and the MN and HN (10 and 15 g/m2) treatments under NTY. Overall, our study offers crucial insights into the conservation, management, and restoration of grassland ecosystems on the Bayinbruck Plateau. It underscores the significance of N addition effects on plant communities, vegetation restoration, and soil properties.

Spatial variations and vertical migration potentials of petroleum hydrocarbons with varying chain lengths in soils of different depths: Roles of solid and dissolved organic matters and soil texture

Petroleum hydrocarbons (PHs) in contaminated sites may threaten human health and ecological safety, while the environmental behaviors of PHs with varying carbon chains and critical influencing factors need to be elucidated, thus facilitating efficient risk management. This study explored the occurrence characteristics and spatial variations of different PHs at the depths of 0–10 m in an abandoned industrial site, as well as evaluated the effects of solid organic matter (SOM), dissolved organic matter (DOM), and soil texture on the migration potentials of PHs with varying carbon chains. Furthermore, the leaching potentials of different PHs were integrated into their risk assessment. The total concentrations of PHs in contaminated soils ranged from 22.7 to 397 mg/kg in contaminated soils, and the long-chained PHs (C22-C40) represented the major components with an average contribution of 46.9 %, followed by short-chained PHs (C10-C12, 32.0 % average) and medium-chained PHs (C13-C21, 21.1 % average). As soil depth increased, a declining trend was observed in the proportions of long-chain PHs, with an augmentation in the relative abundance of short-chain PHs. The random forest model coupling redundancy analysis showed that SOM was the major contributor to the occurrence and vertical attenuation of PHs with longer carbon chains in underground soils, with clay component exerting a greater additional effect than silt and sand components. While DOM in soils exhibited a relatively high contribution to the retention of PHs with short carbon chains. These results demonstrated the significant influence of SOM and clay on the behavior of long-chained PHs and DOM on that of short-chained ones. Besides direct human exposure, the leaching potentials of PHs, particularly short-chained ones, in soils should be considered for a more comprehensive risk assessment. The findings of this study may assist with the behavior modelling and prediction of different PHs as well as the corresponding risk control.

Study on the Influence of Sludge Biochemical Characteristics and Treatment Conditions on Rheological Properties

Abstract In response to the differences in the organic matter, oil and other components of temporary sludge stored in different storage areas of Shanghai Lao-gang, which affect the long-distance transportation of sludge, a full range sampling was conducted on the temporary sludge. Based on the results of solid content measurement, the pH value, mineral oil, total nitrogen, organic matter content, total oil and other six selected sludge samples were subjected to biochemical testing, and one sludge sample was selected for drying and concentration treatment. At the same time, sludge rheological tests were conducted on the biochemical testing sludge samples and the concentrated sludge samples, and the impact of sludge biochemical characteristics and sludge concentration on sludge rheological characteristics was compared and analyzed, which provide reference for the construction process of temporary sludge transportation.

Cocoa pod husk-derived organic soil amendments differentially affect soil fertility, nutrient leaching, and greenhouse gas emissions in cocoa soils

The depletion of soil nutrients and decline in yields on cocoa farms in west Africa over time force farmers to abandon their farms and look for new fertile land, thereby contributing to deforestation. Cocoa pod husks (CPH) are a major farm waste representing considerable export of nutrients from cocoa soils, particularly P and K. Here, the impacts of soil amendment with raw CPH residues, CPH compost, CPH biochar, or a CPH compost-biochar mixture on soil fertility, greenhouse gas (GHG) emissions, and nutrient losses via leaching were assessed in two laboratory experiments using two major soil types used for cocoa cultivation in Ghana (an acidic Ferralsol and an alkaline Nitisol). In Experiment 1, soil nutrient availability and CO2 and N2O emissions were quantified, whereas simulation and quantification of nutrient leaching were conducted in Experiment 2. Soil pH increased from 4.8 and 8.6 by 1.4- and 1.1-folds on average in amended Ferralsols and Nitisols, respectively. Soil electrical conductivity increased in soils amended with CPH compost and/or biochar. Addition of raw CPH caused remarkable microbial immobilisation of N and reduced N availability and leaching, whereas CPH compost and/or biochar addition increased soil nitrate availability but reduced soil ammonium availability. Leaching of Ca in Nitisols was reduced when CPH biochar was included in the soil amendment. While soil K availability increased in all amended soils, most notably when CPH biochar was included, soil P and Ca availabilities were greatest where CPH compost was included. Soil total GHG emission (CO2 plus N2O) increased in all amended Ferralsols and the Nitisols amended with CPH compost or raw CPH, with the latter remarkably increasing soil CO2 emission by up to 14.8-folds. Compared to sole CPH compost amendment, CPH compost-biochar mixture amendment reduced soil total GHG emission and N and P leaching. These findings show that composted and/or pyrolysed CPH can be judiciously used to enhance soil fertility in cocoa farms, particularly in acidic soils. Pyrolysed CPH is especially beneficial for reducing soil nutrient leaching and GHG emissions and thus for increasing the sustainability of cocoa production in Ghana and west Africa.

Forest Dieback Alters Nutrient Pathways in a Temperate Headwater Catchment

ABSTRACTForested headwater catchments ensure good water quality for downstream ecosystems and human consumption. Climate change and the exacerbating likelihood of extreme events elevate the risk of severe forest dieback. However, the effects of forest dieback on the quantity and quality of stream water are not fully understood. Here, we analyse high‐frequency observations of discharge, electrical conductivity (EC), dissolved organic carbon (DOC) and nitrate (NO3N) obtained before, during and after a drought‐induced forest dieback in a headwater stream in the German Harz Mountains. We focus on the characteristics of concentration‐discharge (C‐Q) relationships at the scale of runoff events to assess the effects of forest dieback on the sources, mobilisation and pathways of EC, DOC and NO3N. When comparing pre‐ and post‐dieback conditions, we found a significant increase in runoff efficiency and a doubling of DOC loads exported from the catchment, while DOC concentrations increased only moderately and their C‐Q patterns did not change. EC exhibit no changes in concentrations but a steepening of C‐Q dilution patterns. We explain these findings with a dieback‐induced decrease in evapotranspiration, which leads to more intensive drainage of the upper organic soil layers in the riparian zone. In contrast, we observed a strong increase in NO3N concentrations and fluxes by a factor of ~5, while C‐Q patterns at the event scale changed from enrichment to dilution. We argue that the dieback led to an excess of NO3N on the hillslopes that connect to the stream via surficial flowpaths. In this way, NO3N bypasses the riparian zone, reducing the catchment's efficiency in attenuating this nutrient. Our study emphasises the pivotal role of riparian zones in mediating water quality in headwater streams. Different configurations of the riparian zone and its connection to the hillslopes and the stream network may be a missing piece in explaining differences in water quality responses of catchments to forest dieback.

Effects of fire and fire-induced changes in soil properties on post-burn soil respiration

Abstract Background Boreal forests cover vast areas of land in the northern hemisphere and store large amounts of carbon (C) both aboveground and belowground. Wildfires, which are a primary ecosystem disturbance of boreal forests, affect soil C via combustion and transformation of organic matter during the fire itself and via changes in plant growth and microbial activity post-fire. Wildfire regimes in many areas of the boreal forests of North America are shifting towards more frequent and severe fires driven by changing climate. As wildfire regimes shift and the effects of fire on belowground microbial community composition are becoming clearer, there is a need to link fire-induced changes in soil properties to changes in microbial functions, such as respiration, in order to better predict the impact of future fires on C cycling. Results We used laboratory burns to simulate boreal crown fires on both organic-rich and sandy soil cores collected from Wood Buffalo National Park, Alberta, Canada, to measure the effects of burning on soil properties including pH, total C, and total nitrogen (N). We used 70-day soil incubations and two-pool exponential decay models to characterize the impacts of burning and its resulting changes in soil properties on soil respiration. Laboratory burns successfully captured a range of soil temperatures that were realistic for natural wildfire events. We found that burning increased pH and caused small decreases in C:N in organic soil. Overall, respiration per gram total (post-burn) C in burned soil cores was 16% lower than in corresponding unburned control cores, indicating that soil C lost during a burn may be partially offset by burn-induced decreases in respiration rates. Simultaneously, burning altered how remaining C cycled, causing an increase in the proportion of C represented in the modeled slow-cycling vs. fast-cycling C pool as well as an increase in fast-cycling C decomposition rates. Conclusions Together, our findings imply that C storage in boreal forests following wildfires will be driven by the combination of C losses during the fire itself as well as fire-induced changes to the soil C pool that modulate post-fire respiration rates. Moving forward, we will pair these results with soil microbial community data to understand how fire-induced changes in microbial community composition may influence respiration.

Long‐Term Effects of Arable and Tree Cropping Systems on Soil Organic Carbon and Nitrogen Dynamics in a Tropical Agroecological Transition Zone

ABSTRACTContinuous cropping can affect soil carbon and nitrogen stocks and litter decomposition, but research on smallholder farms in Africa is limited. This study, conducted from 2020 to 2023 in Ghana's forest‐savanna transition zone, examined four cropping systems: continuous maize monocrop (M), maize rotated with legumes (ML), young cashew intercropped with maize or legumes (YCM/L), and mature cashew (MC). The objective was to assess the long‐term impact of the cropping systems on soil organic carbon (SOC), nitrogen (N) stocks, and soil organic matter (SOM) decomposition rates using the tea bag protocol. Results showed significant variability in SOC and N stocks across the systems. At a 0–15 cm depth, SOC in the MC and M systems was 160% and 149% higher than in the YCM/L system. At 15–30 cm, SOC in the M and MC systems was 86% and 132% higher than in YCM/L. Soil nitrogen stocks followed a similar trend, with MC and M systems showing 94%–199% higher values than YCM/L at both depths. SOM decomposition rates for green and rooibos tea in the MC and ML systems were statistically similar after 90 days of incubation (p > 0.05). This study, the first to use the tea bag protocol in Ghanaian soils, revealed that mature cashew and sustainable practices, such as adding maize stover, can enhance SOC and N stocks in highly weathered tropical soils. These findings underscore the potential for specific cropping systems to improve soil health on smallholder farms.

Comparison of two gamma-ray datasets measured with different methods and assessment of their performance to predict soil properties

ABSTRACT Terrain mobility is directly dependent on soil properties, i.e. stoniness, soil particle size and peat depth. Gamma-ray spectrometry has been widely used in soil mapping as gamma-rays can penetrate up to 50 cm of soil. The method has proven to be effective in gathering information on various soil properties, such as clay and silt content, organic carbon content, soil pH, and soil stoniness. The intensity of gamma radiation decreases with increasing soil moisture content, which is important when assessing the load-bearing capacity of forest terrain, which affects the quality and planning of mechanized wood harvesting. In this study, we compared two gamma-ray datasets that were acquired from the same plots but measured with different methods: airborne gamma-ray spectrometry and a handheld gamma-ray spectrometer. Regression analyses were used to examine whether the gamma-ray datasets have significant similarities. Linear discriminant analysis was then used to study the performance of the two gamma-ray datasets when predicting different soil properties (stoniness index classes (SIC), soil depth, and peat depth). Our correlation analysis produced R2 values of 0.18–0.29 and root mean square error (RMSE%) values of 0.48–0.55. Prediction of SIC was 67.1% accurate with ground gamma and 45.9% accurate with air gamma. For soil depth predictions, the accuracies were 64.7–70.0% for ground gamma and 61.7–63.5% for air gamma. Our findings showed that ground gamma-ray spectrometry is better at predicting soil properties than air gamma-ray spectrometry.

Superhydrophobic/superoleophilic polyurethane /reduced graphene oxide/ sponge for efficient oil-water separation and photothermal remediation

Due to the rapid development of global industrialization, the frequent occurrence of organic matter leakage and oil leakage accidents has led to increasingly serious environmental pollution. Therefore, this paper has proposed a facile and affordable method for creating oil water separation materials, and successful creating a super hydrophobic/super oleophilic functional porous polyurethane sponge modified by reduced graphene oxide and polydopamine (PDA-rGO-PU). Dopamine undergoes a self-polymerization event that creates polydopamine, which is subsequently coated on a polyurethane framework to create a sponge structure with several active sites. The surface of the modified sponge structure was coated with graphene oxide by a simple drop-coating method, and graphene oxide coated on the surface of polydopamine was reduced to create the superhydrophobic/superoleophilic material. The PDA-rGO-PU demonstrated strong anti-adhesion properties and a high oil-water separation efficiency of 99.8 % while having high water contact angles of 155 ° ± 3 ° and oil contact angles (OCA) of 0 °. It has a strong ability to adsorb various oils and organic solvents, the excellent photothermal effect allows PDA-rGO-PU to raise temperature by 37.9 % in the presence of light. PDA-rGO-PU has good continuous oil sorption performance after installing the pump. When under simulated lighting conditions, the sorption time of modified sponge on crude oil was shortened by 2.3 times.

The effects of earthworm species on organic matter transformations and soil microbial communities are only partially related to their bioturbation activity

Earthworms are pivotal in shaping soil ecological processes through their bioturbation activity and organic matter consumption. Earthworm species are known to have different impacts on soil structure, but only a small number of species have been studied so far, and few studies have examined how earthworms simultaneously affect soil functions. Here, we measured the impact of different earthworm species on soil structure (bioturbation function), carbon (C) and nitrogen (N) dynamics and the microbial community (organic matter transformation function), while exploring the links between these functions, across distinct soil compartments (surface casts, below-ground drilosphere, and bulk soil). Six earthworm species (Lumbricus terrestris, Allolobophora chlorotica, Octolasion cyaneum, Octodrilus complanatus, Aporrectodea caliginosa meridionalis and Microscolex dubius) of different ecological categories and functional groups were incubated in soil cores with soil and alfalfa litter for 6 weeks. Our results on the bioturbation function illustrated a great diversity of behaviors and confirmed the relevance of a functional classification based on bioturbation metrics. The main microbial hotspots were surface casts, whose characteristics allowed to distinguish two groups of species. Octod. complanatus, L. terrestris and M. dubius induced high humidity (respectively, +57, +48, +74%), high C (respectively, 19.9, 24.8, 33.2 g kg⁻1 dry soil) and N (respectively, 2, 2.3, 3.2 g kg⁻1 dry soil) content and microbial community selection, promoting C and N mineralization. The three other species had a lower impact. The below-ground drilosphere only showed specific characteristics in the case of L. terrestris. The effects of the studied species on the organic matter transformation function did not align with their bioturbation activities nor with their ecological category. These findings show that the contribution of earthworms to C and N turnover is only partially dependent on their bioturbation effects and suggest the usefulness of developing distinct functional groups based on the specific soil functions under consideration.

Effect of Soil Application of Organic Amendments on Flowering and Yield Parameters of Chilli (Capsicum annuum L.)

The present investigation was conducted at Department of Plant physiology, College of Agriculture, Vellayani during the period from January 2023 to May 2023 with an objective to evaluate the effect of soil application of organic amendments on flowering and yield parameters of chilli (Capsicum annuum L.). Research was conducted to identify the best organic soil amendment suited to the chilli variety, Vellayani Athulya. Work consisted of 8 treatments and 3 replications with the design simple CRD. The treatments were T1-Control 1 [KAU Organic POP (OPOP) (2017) with FYM (25 t ha-1)], T2-Control 2 [KAU POP (2016)], T3-FYM substituted with vermicompost (12.5 t ha-1) as per KAU OPOP (2017), T4 -FYM substituted with goat manure (1t ha-1) as per KAU OPOP (2017), T5 -T1+ Rice husk biochar (0.5% w/w), T6- T2+ Rice husk biochar (0.5% w/w), T7- T3+ Rice husk biochar (0.5% w/w ) and T8- T4+ Rice husk biochar (0.5% w/w). The results revealed that the treatment T8-FYM substituted with goat manure (1t ha-1) as per KAU Organic POP(OPOP) (2017)+ rice husk biochar (0.5% w/w) resulted in better flowering and yield attributes in chilli. Also the same treatment showed superior performance in terms of number of flowers plant-1 (44.67), days to first flowering (22 days), days to first harvest (41 days), percentage of fruit setting (64.18%), number of fruits plant-1 (28.67), fruit length (15.30cm), fruit girth (9.30cm), fruit weight (17.70 g fruit -1) and yield (507.41 g plant-1). Thus, the combined application of goat manure (1t ha-1) as per KAU OPOP + rice husk biochar (0.5% w/w) proved to be a better soil organic amendment for chilli variety Vellayani Athulya.

Extractable soil silicon in relation to sugarcane yield on mineral soil

Florida sugarcane production is mostly on organic soils, but the cultivation area on mineral soils is also expanding. Silicon (Si) is beneficial for sugarcane growth and development on weathered soil. However, the low solubility and availability of soluble Si is an issue in Florida’s mineral soils. This study aimed to assess soil Si extraction methods based on sugarcane yield response to calcium silicate application. It also examined the relationship between sugarcane yield with extracted plant-available soil Si, alongside plant Si concentrations. The experiment followed a randomized complete block design involving 2 fields, with 24 plots each, and 6 replications. Four rates of calcium silicate (0 control, 2.24, 4.48, and 6.67 Mg ha−1) were applied before planting sugarcane. Soil samples were collected prior to planting and after each harvest. Soil Si was extracted using 0.5 M acetic acid, 0.7 N NH4OAc, Mehlich 3, and 0.01 M CaCl2 extractants. Leaf samples were collected over a three-year sugarcane life cycle (from 2019 to 2022) to evaluate the relationship between soil Si and leaf Si concentrations. The relationships between parameters were analyzed using linear and nonlinear regression models. Results indicated that higher Si application rates increased Si concentrations in sugarcane leaves in both fields. However, only one field showed a yield response to Si, likely due to high pre-plant soil Si in the other field. The best extractant should correlate strongly with either yield or leaf Si content, but no single extractant showed a strong correlation with either, making it infeasible to identify the best extractant.

Evolution of hydrochemical characteristics and the influence of environmental background in the Hailar River basin, China.

Understanding the evolution of hydrochemical characteristics in river systems is essential for environmental assessment and water resource management. This study explores the spatiotemporal distribution and the determinants of hydrochemical characteristics in the Hailar River basin, China, over an extensive period. Our results revealed that CODMn and CODCr were the primary concerns for long-term river management, with exceedance rates of 42.92% and 50.62%, respectively. These exceedances were predominantly driven by interactions between riparian soils and surface water, rather than anthropogenic pollution, as suggested by the strong correlations between dissolved organic carbon and soil water-extractable organic carbon, and the limited human footprint in this region. Piper trilinear and Gibbs diagram analysis further revealed that long-term rack weathering shaped the basin's hydrochemical characteristics, resulting in distinct HCO3--Ca2+ and HCO3--Ca2+-Na+ signatures. In addition, APCS-MLR analysis identified that elevated of CODMn and CODCr levels were mainly attributed to the interactions with adjacent soils, which are extensively covered by forests and grasslands. In contrast, leaching and migration processes contributed significantly on total dissolved solids and total phosphorus. The study also found that environmental self-purification processes played a key role in regulating Fe concentrations. This investigation provides a nuanced understanding of the environmental background's influence on hydrochemistry and dissolved organic matter (DOM) in the Hailar River basin, which offers valuable insights and methodologies for the rational assessment of water quality and aquatic ecosystem health in similar riverine systems.

The Effects of Meander Reconnection and Deflector Installation on the Physicochemical Water Quality

ABSTRACTRiver restoration efforts are gaining momentum in response to the pressing need for resilient river systems, in light of escalating climate change impacts. However, achieving predefined restoration goals remains challenging due to insufficient understanding of river system responses. Of particular complexity is assessing the success of restoration measures on water quality, a critical abiotic factor in freshwater ecosystems. This study examined the impact of meander reconnection and deflector placement on water quality. Two distinct meander sections and a degraded section were meticulously sampled both upstream and downstream to assess impacts. The meander sections were reconnected using different approaches: one fully reconnected, receiving all discharge, and the other partially reconnected, receiving part of the discharge while maintaining the channelized trench. The results showed promising potential of reconnected meanders for mitigating phosphorus and carbon levels. However, the effectiveness of these improvements was compromised by deflector placement, which led to increased erosion and release of phosphorus bound to organic soil particles. Conversely, dissolved nutrients (e.g. nitrate, orthophosphate, DOC) exhibited no significant alterations, likely attributed to the absence of macrophytes and the limited extent of restorative actions, which currently do not increase water residence time sufficiently. Temporal trends revealed progressive reductions in carbon, phosphorus, and nitrogen levels suggesting that time is a crucial factor in restoration success, possibly due to soil stabilization. Seasonal dynamics also played a significant role, with discernible effects observed primarily during summer. This study underscores the importance of long‐term, watershed‐scale investigations that account for seasonal variability to fully understand the impacts of river restoration.

Stabilization effect of nano-SiO2@iron-phosphorus on ferrallisols, calcareous soil and organic soil heavily polluted by heavy metals: A fast reaction curing stabilization process

The remediation of soil pollution by heavy metals (HMs) presents a significant challenge in environmental restoration. Stabilization remediation technology has proven effective in treating HMs contaminated soil. However, its development is constrained by drawbacks such as slow reaction kinetics and low adsorption capacity. This research synthesized a nano-SiO2@iron‑phosphorus (FPOH) material by SiO32− encapsulating the iron-phosphate precipitate obtained from Fe ion and phosphate. In addition, this research applied this material to ferrallisols, calcareous soils and organic soils with three different levels of high pollution by Cd, Pb, Cu and Zn. The experimental results indicate that all experimental soils stabilized rapidly within 1 day and met the requirements of remediation engineering standards (ChinaMEE HJ 1282-2023). Analysis of the possible mechanisms suggests that the FPOH material effectively fills voids with phosphate mineral formation, preventing the secondary release of HMs. During the stabilization process, FPOH involves the adsorption of free ions and small organic molecules in the soil, which does not affect its high reactivity. The development and utilization of FPOH offer valuable insights for soil stabilization remediation.

Effect of potassium fulvate on continuous tobacco cropping soils and crop growth.

Long-term continuous cropping of tobacco causes dysbiosis of soil microbial communities, the imbalance of soil nutrients, and the increase of pathogenic bacteria, which will slow the growth and development of tobacco plants, reduce the production quality, and cause significant losses to tobacco production and tobacco farmers. The application of Potassium fulvic acid can not only provide nutrients, but also inhibit the propagation of pathogens in soil along with raising the amount of organic matter in the soil, which is an effective way to improve soil health. In this experiment, Tobacco variety SNT60 was used as the test material, and 6 treatments were set up by pot test, they were: no fertilisation control group (CK), tobacco special fertiliser (NPK), 3.45 g/kg of potassium fulvic acid fertiliser (T1), 4.65 g/kg of potassium fulvic acid fertiliser (T2), 5.85 g/kg of potassium fulvic acid fertiliser (T3), 7.05 g/kg of potassium fulvic acid fertiliser (T4), Ten replications were set up for each treatment and the soil and fertiliser were mixed and potted before transplanting, 70% as basal fertiliser and 30% as supplementary fertiliser. We also analyzed soil properties, soil microorganisms and agronomic traits of tobacco plants in different treatments to provide reference for mitigating tobacco succession barrier. The test results are as follows: 4.65 g/kg of potassium fulvic acid fertiliser (T2) treatment was the best, soil organic matter, quick nitrogen, phosphorus, potassium, pH, soil catalase, soil sucrase, and soil urease content, compared to CK control, increased by 22.04%, 43.12%, 96.21%, 381.79%, 25.43%, 91.69%, 262.07% and 93.16%. In terms of microbial community, application of potassium fulvic acid fertiliser significantly increased the relative abundance of Ascomycetes, Chlorobacterium, Bacillus, Proteobacteria and Tephritobacterium in the soil. Meanwhile, 4.65 g/kg of potassium fulvic acid fertiliser (T2) promoted the growth of tobacco plants, improved leaf photosynthetic capacity, and enhanced plant disease resistance. This experiment provides practical measures to improve the microbial community of tobacco continuous cropping soils and to reduce the incidence of diseases.

Clay Minerals and Long-Term Fertilization Effects on Soil Organic Carbon Stocks, Soil Carbon Pools, and Soil Enzymes in an Inceptisol of Coimbatore, Tamil Nadu

ABSTRACT Soil Organic Carbon (SOC) is an important indicator for soil health and quality. The present study was conducted in five-decade-old Long-Term Fertilizer Experiment involving the finger millet−maize cropping sequence in an Inceptisol to examine the effects of inorganic fertilizers and manures on soil organic carbon stock in relation to C sequestration. This study was based on 10 treatments: 50%NPK, 100%NPK, 150%NPK, 100%NPK + HW, 100%NPK + ZnSO4, 100%NP, 100%N, 100%NPK + FYM, 100%NPK (− S), and control. We assess the clay mineral interaction with soil organic carbon stock and soil enzyme activity. The semi-quantification and characterization of clay minerals were sourced from X-ray diffraction (XRD) analysis, and the SOC stock was calculated based on SOC concentration, Bulk density, and Depth. From the study, results revealed that clay minerals were studied by XRD and FTIR spectroscopy analysis. The results revealed that dominant clay minerals in the experimental soil were in the order of Montmorillonite, 2:1 interstratified minerals, Vermiculite, and Illite, and the buildup of SOC stock raised from 6.3 Mg C ha−1 to 12.9 Mg C ha−1 over five decades. The maximum SOC stock of 12.9 Mg ha−1 was recorded in 100% NPK + FYM while the control registered 7.5 Mg C ha−1. The study conclude that balanced fertilization of 100% NPK with FYM contributed toward the increase in SOC, SOC stock, and carbon sequestration for improving soil fertility status.

Apple leaf-inspired bilayered Janus wood evaporator with decoupled light-vapor interfaces for high-efficiency solar steam generation

Solar-driven interfacial evaporation technology provides a facile and promising strategy for producing clean water from seawater. Wood-based evaporators have recently been extensively explored for solar desalination due to the structural merits and sustainability of natural wood. However, the light absorption and water evaporation functions are commonly integrated at the same surface for a traditional wood-based solar evaporator, which definitely causes mutual interference between the incident sunlight and the generated vapor leading to inevitable energy loss. Herein, inspired by the unidirectional transpiration of hypostomatic apple leaves, a bilayered Janus wood evaporator with decoupled light absorption and water evaporation surfaces was subtly engineered to avoid the sunlight-vapor interference for efficient solar evaporation. The bilayered evaporator consists of a longitudinal wood piece as the water transport layer and a carbonized transverse wood piece infiltrated with polydimethylsiloxane (PDMS) as the photothermal layer. The hydrophilic longitudinal piece with vertically aligned channels can continuously wick water to the evaporation surface, while the hydrophobic transverse piece with horizontal channels enables efficient heat transfer given its high thermal conductivity. Thanks to the unique bilayered configuration, the developed evaporator demonstrates an excellent evaporation rate of 2.12 kg m−2 h−1 with an evaporation efficiency of 92.3 % (1 sun), surpassing most of the traditional wood-based evaporators. Moreover, the bilayered evaporator exhibits good salt resistance and can effectively purify diverse wastewaters including organic dye solutions and oil–water emulsions. This Janus-interface structural design provides a novel strategy for developing high-performance solar evaporator toward clean water production.

Characterization of Wastewater in an Activated Sludge Treatment Plant of the Food Sector

Recently, water has become a resource that generates controversy due to shortage alarms and high consumption by production companies. Making good use of water has become the main objective of government institutions. The food industry generates a large amount of wastewater, concentrating the largest number of contaminants originated in its processes. Wastewater from the food industry is characterized by having a large amount of organic matter, especially fats and oils, as well as suspended solids. The objective of this research is to carry out a characterization of effluents generated in a wastewater treatment plant in the food sector based on Mexican and international regulations to determine whether it is reusable. This article addresses Mexico’s lag in the reuse of treated wastewater in the face of the water crisis, highlighting the urgency of adopting these practices to mitigate water scarcity. For the development of this investigation, samples were collected at the discharge point produced by the company’s effluents, followed by an evaluation of their physical, chemical, and biological parameters, and finally, it was determined that the effluent follows the regulatory standards for discharge into the city sewer but outside the range for reuse in productive processes or irrigation of green areas.

Soil Formation on Loamy Deposits in Technogenic Landscapes of the Taiga Zone in the North-Eastern Part of European Russia

The paper highlights the influence of moisture on the soil formation process on loamy deposits during the primary vegetation succession. The study was carried out in the north-eastern part of European Russia (Komi Republic) in the middle taiga subzone. The authors analyzed young soils on the territory of a quarry for extraction of loamy grounds and background soils in the vicinity of it. Planting the Siberian spruce cultures on the territory of the quarry activated formation of the tree layer and thereby accelerated formation of the zonal type soils. The third succession decade in drained conditions saw formation of organic soil horizons (litters), a decrease in soil density in the upper profile part, a tendency to redistribute and differentiate the silty fraction by one-and-a-half oxides, indicating the beginning of selective podzolization. The rise in soil moisture content increased conservation of organic residues (peat formation) and made gley formation active. The quarry soils, like background soils, increased in acidity, carbon and nitrogen reserves along with the soil moisture content increase. In automorphic soil formation conditions, the rate of organic carbon accumulation in the upper 0–20-cm layer is 0.4 t· ha–1·year1; the excessive soil moisture content further increased it (1.0–1.2 t·ha–1·year1). The reserves of Corg in the upper 20-cm soil layer of young soils are by 2–4 times less than those in background soils.