Search Results (324)

Cassava is the sixth most important food crop and is cultivated in more than 100 countries. The crop tolerates low soil fertility and drought, enabling it to play a role in climate adaptation strategies. Cassava generally requires careful preparation to remove toxic hydrogen cyanide (HCN) before its consumption, but HCN concentrations can vary considerably between varieties. Climate change and low inputs, particularly carbon and nutrients, affect agriculture in Pacific Island countries where cassava is commonly grown alongside traditional crops (e.g., taro). Despite increasing popularity in this region, there is limited experimental data about cassava crop management for different local varieties, their relative toxicity and nutritional value for human consumption, and their interaction with changing climate conditions. To help address this knowledge gap, three field experiments were conducted at the Koronivia Research Station of the Fiji Ministry of Agriculture. Two varieties of cassava with contrasting HCN content were planted at three different times coinciding with the start of the wet (September-October) or dry (April) seasons. A time series of measurements was conducted during the full 18-month or differing 6-month durations of each crop, based on destructive harvests and phenological observations. The former included determination of total biomass, HCN potential, carbon isotopes (δ¹³C), and elemental composition. Yield and nutritional value were significantly affected by variety and time of planting, and there were interactions between the two factors. Findings from this work will improve cassava management locally and will provide a valuable dataset for agronomic and biophysical model testing. Full article

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

Due to soil nutrient depletion and rising food demand from an increasing global population, it is essential to find sustainable ways to boost crop yields, improve soil health, and address the environmental issues induced by agriculture. The most appropriate approach is to consider sustainable amendments, such as biochar and its derivatives, which are vital constituents of soil health due to their affordability, low reactivity, large surface area, and reduced carbon footprint. In this context, biochar and its derivatives in farming systems focus on improving soil structure, nutrient holding capacity, microbial activities, and the perpetuation of soil fertility. Despite its benefits, biochar, if it is used in high concentration, can sometimes become highly toxic, causing soil erosion due to reducing surface area, increasing pH levels, and altering soil properties. This review highlights the production methods and sources of feedstocks, emphasizing their important contribution to the soil’s physicochemical and biological properties. Furthermore, it critically evaluates the environmental applications and their impacts, providing data built upon the literature on contaminant removal from soil, economic factors, heavy metal immobilization, carbon sequestration, and climate resilience. This review emphasizes the main challenges and future prospects for biochar use in comparison to modified biochar (MB) to propose the best practices for sustainable farming systems. Full article

Urban forests provide essential ecosystem services, including improving soil health, sequestering carbon (C), and supporting biodiversity. However, the effects of anthropogenic litter and root management on soil biogeochemical processes in urban environments remain poorly understood. This study applied the Detritus Inputs and Removal Treatment (DIRT) framework to examine how aboveground and belowground organic inputs influence soil organic carbon (SOC), total nitrogen (TN), soil water content (SWC), and enzymatic activities in subtropical urban camphor tree forests in China. Six treatments were implemented: litter removal (LR), litter addition (LA), root exclusion (RE), combined litter and root removal (LR + RE), combined litter addition and root exclusion (LA + RE), and an undisturbed litter control (LC). The results showed that the LA treatment significantly enhanced SOC, TN, SWC, and key soil enzyme activities (protease, catalase, and urease) compared to the LC, highlighting the crucial role of litter in enhancing soil fertility and microbial functioning. These elevated enzyme activities suggest intensified microbial nutrient cycling and metabolic activity in response to organic matter inputs. In contrast, the combined LR + RE treatment reduced SOC and enzyme activities but unexpectedly increased TN, indicating disrupted nutrient cycling, possibly due to accelerated microbial nitrogen mineralization and decomposition of existing soil organic matter in the absence of fresh carbon inputs. The LA treatment also showed the highest carbon-to-nitrogen (C:N) ratio, reflecting a carbon-enriched environment that may favor long-term carbon stabilization. Additionally, SWC was most improved under the LA + RE treatment, suggesting its potential for enhancing soil moisture retention in urban settings. These findings underscore the complementary roles of litter and root inputs in maintaining soil health and biogeochemical balance in urban forests. The study provides insights into enzyme-mediated soil processes under varying organic input regimes and highlights the value of targeted organic matter management to enhance urban ecosystem services. Full article

Spartina alterniflora invasion has posed severe ecological threats to coastal wetlands. Deep tillage is considered an effective physical method for ecological restoration in such wetlands; however, its effects on sediment nitrogen transformation processes remain unclear. In this study, we investigated the impacts of deep tillage on soil physicochemical properties and key nitrogen transformation pathways, including nitrification, denitrification, anammox, and DNRA, across different soil depths (0–10, 10–20, 20–30, 30–50, and 50–100 cm) in Spartina alterniflora-invaded coastal wetlands. Deep tillage significantly restructured the distribution of soil moisture (p < 0.05), pH (p > 0.05), electrical conductivity (p < 0.05), and nutrients, promoting NO₃⁻-N accumulation in deeper layers while reducing NH₄⁺-N concentrations in surface soils (p < 0.05). It markedly enhanced denitrification and DNRA rates (p < 0.05), suppressed surface nitrification (p < 0.05), and altered the vertical distribution of anammox activity. Correlation analysis revealed that NH₄⁺-N and NO₃⁻-N concentrations were the primary drivers of nitrogen transformation, with pH and electrical conductivity playing secondary roles. Overall, deep tillage stimulated nitrogen removal processes and affected net ammonium changes. These findings reveal that deep tillage can stimulate nitrogen removal processes by alleviating soil compaction and altering nitrogen transformation pathways, thus supporting biogeochemical recovery mechanisms after deep tillage. These insights provide scientific guidance for the ecological restoration of Spartina alterniflora-invaded coastal wetlands. Full article

Long-term irrational farming practices and low return of organic materials to the fields in the black soil area have led to reduced soil carbon and nitrogen stability and nutrient imbalance, which in turn affect soil fertility and crop yields. Straw return is an effective way to enhance soil organic matter and crop productivity, but the effects of long-term straw return under tilling practices on carbon and nitrogen sequestration and soil microbial stoichiometric equilibrium in black soil need to be further investigated. This study investigated the physical, chemical and biological properties of the 0–60 cm soil layer under deep tillage with straw return to the field (DTS), deep harrow with straw return to the field (DHS), rotary tillage with straw return to the field (RTS), no tillage with straw return to the field (NTS), and conventional tillage with straw removal (CT) on the basis of seven consecutive years of tillage pattern location trials in the black soil area of eastern Inner Mongolia. The results showed that DTS and NTS significantly increased the soil organic carbon (SOC), soil total nitrogen (TN), soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN) contents, and the SOC/TN ratio in the 0–40 cm soil layer, enhancing soil carbon and nitrogen sequestration capacity, while the concomitant increase in the average MBC/MBN ratio in the plow layer from 6.8 to 8.2. The soil microbial quotient increased by 29.0% and 26.2%, respectively, and the stoichiometric imbalance ratio decreased by 7.9% and 5.7%, respectively. Meanwhile, in terms of maize yield from 2018 to 2024, DTS showed the most stable and significant yield increase with 41.53%. Whereas NTS showed a higher yield increase potential with a 27.36% increase in yield as the number of years of straw return increased. Therefore, DTS and NTS are superior tillage methods to improve the quality of the black soil tillage layer, to promote soil microbial carbon and nitrogen balance, and to increase crop yields. Full article

Nitrogen is a vital nutrient and plays a pivotal role in maintaining ecosystem equilibrium. Owing to human activities, particularly industrial production, vehicle emissions, fossil fuel combustion, and the improper use of chemical fertilizers, nitrogen pollution has emerged as a pressing global environmental issue. It exacerbates air pollution, water eutrophication, and soil acidification, all of which pose profound risks to both ecosystems and human health. This review conducts a holistic analysis of nitrogen sources and the current status of nitrogen pollution, with a particular focus on the treatment of nitrogen-laden wastewater. It assesses various nitrogen pollution remediation technologies, including biological and physicochemical methods. In recent years, the application of novel metal–phenolic networks (MPNs) has garnered considerable scholarly attention. As innovative materials, it has been demonstrated that MPNs have great potential in nitrogen removal. For example, studies have demonstrated that iron–tanninate has the capacity to remove over 95% of ammonium nitrogen. Despite the progress made with current remediation methods, each approach has inherent limitations, such as long treatment durations, high energy demands, and poor selectivity for diverse nitrogen pollutants. Therefore, sustained research endeavors and technological innovation are indispensable for advancing nitrogen pollution control technologies. It is against this backdrop that we conducted this review. This study summarizes and analyzes the current status of nitrogen pollution and nitrogen removal technologies, and provides an overview of novel nitrogen removal MPNs. MPNs are promising and innovative materials with great potential, although current research is still at the laboratory stage and is ongoing. Full article

Stormwater carries significant amounts of pollutants—including metals, microorganisms, organic micropollutants, and nutrients—from land surfaces into nearby water bodies, leading to water quality deterioration and threats to both human health and ecosystems. The removal of these contaminants is essential not only for environmental protection, but also to enable the reuse of treated water for various beneficial applications. Common treatment methods include bioretention systems, biofiltration, constructed wetlands, rain gardens, swales, and permeable pavements. To improve pollutant removal efficiency, adsorbent materials are often incorporated into the soil substrate of these treatment devices. However, most research on adsorbents has focused on their effectiveness against one or two specific pollutants and has been conducted under static, short-term laboratory conditions rather than dynamic, field-relevant scenarios. Column-based dynamic filtration type studies, which are more informative for field applications, are limited. In one study, a combination of two or more adsorbents with contrasting properties that matched the affinity preferences of the different pollutants to the substrate media removed 77–100% of several heavy metals that occur in real stormwater compared to 38–73% removal with only one adsorbent. In another study, polycyclic aromatic hydrocarbon removal with zeolite was only 30–50%, but increased to >99% with 0.3% granular activated carbon addition. Long-term dynamic column-based filtration experiments and field studies using real stormwater, which contains a wide range of pollutants, are recommended to better evaluate the performances of the combined adsorbent systems. Full article

In this study, Bacillus amyloliquefaciens SQ-2, previously isolated from a commercial watercress paste, was investigated for its potential in promoting rice growth in Pb/Al-contaminated acidic soil, especially when used in conjunction with corn straw biochar. Firstly, the physiological properties of rice were enhanced, with the activities of catalase and superoxide dismutase increasing by 162.5% and 162.9%, respectively. Additionally, the total phenolic and chlorophyll contents of rice increased by 17.6% and 83.7%, respectively. Secondly, the nutrient content of the rice rhizosphere soil was improved. In particular, nitrate nitrogen, available potassium, and sucrase were enhanced by 9.4%, 45.9%, and 466.8%, respectively. Moreover, SQ-2–biochar was demonstrated to have a notable capacity for removing Pb²⁺ and Al³⁺. The mineralization of Pb²⁺ and Al³⁺ was achieved through the use of SQ-2–biochar, as revealed by SEM-EDS, XRD, XPS, and FT-IR analyses, with the main precipitates being Pb₃(PO₄)₂ and AlPO₄. Functional groups such as C-O-C, C=O, N-H, P-O, and -O-H on the microbial surface were found to be involved in the biosorption process of Pb²⁺ and Al³⁺. In summary, SQ-2–biochar can effectively mineralize Pb²⁺ and Al³⁺, enhance the physiological properties of rice, and improve soil nutrients, thereby augmenting the antioxidant capacity, photosynthesis, and stress resistance of rice and ultimately promoting rice growth. Full article

Mineral nutrition management in sweet cherry orchards remains a critical challenge due to the lack of site-specific fertilization guidelines, particularly in Greece, a significant cherry-producing country. This study aimed to develop a predictive framework for total nutrient losses in sweet cherry orchards by proposing simplified estimations using fresh fruit yield as the sole input variable. Field experiments were conducted in two orchards with distinct rootstocks (MxM 14 and CAB-6P), analyzing soil properties, leaf nutrient status, and uptake patterns on different plant components. Results indicated that despite differences in soil texture and pH, nutrient availability was generally sufficient, with only Fe and Zn marginally below optimal levels in leaf tissue. Principal Component Analysis (PCA) revealed distinct nutrient distribution patterns, with N evenly distributed across fruits, peduncles, and prunings, while K was concentrated in fruits and peduncles, and Ca and Mg predominantly in fallen leaves. Notably, K was redistributed from leaves to fruits under high yields, evidenced by negative correlations between leaf biomass and K uptake. Strong relationships (r² > 0.8) were found between fresh fruit yield and uptake of N, P, K, Mg, B, and Cu, enabling reliable predictions of total nutrient losses. Estimated annual nutrient removals were 85.6 kg ha⁻¹ N, 8.94 kg ha⁻¹ P, 42.7 kg ha⁻¹ K, and 12.0 kg ha⁻¹ Mg, with significant fractions retained in prunings and fallen leaves (e.g., 51.8 kg ha⁻¹ N, 6.2 kg ha⁻¹ P). The developed yield-based models provide a practical tool for optimizing fertilization strategies, while our findings highlight the potential for nutrient recycling through sustainable residue management. Full article

To address the critical challenges of wind erosion mitigation and sustainable soil management in the fragile agroecosystem of the black soil region in the foothills of the Daxing’anling Mountains, this study evaluated five tillage practices—conventional ridge tillage (CP), no tillage with straw removal (NT), no tillage with straw mulching (R+NT), autumn strip tillage with straw mulching (R+ST_A), and spring strip tillage with straw mulching (R+ST_S)—across two landforms: gently sloped uplands and flat depressions. The results demonstrated that R+ST_S achieved superior performance across both landscapes, exhibiting a 42.99% reduction in the wind erosion rate, a 48.88% decrease in soil sediment discharge, and a 52.26% reduction in the soil creep amount compared to CP. These improvements were mechanistically linked to the enhanced surface microtopography (aerodynamic roughness increased by 1.8–2.3 fold) and optimized straw coverage (68–72%). R+ST_S also enhanced the topsoil fertility, increasing the total nitrogen (TN), soil organic carbon (SOC), alkaline nitrogen (AN), available phosphorus (AP), and rapidly available potassium (AK) by 22.07%, 12.94%, 14.92%, 32.94%, and 9.52%, respectively. Furthermore, it improved maize emergence and its yield by 10.04% and 9.99% compared to R+NT. Mantel tests and SEM revealed strong negative correlations between erosion and nutrients, identifying nitrogen availability as the key yield driver. R+STS offers a sustainable strategy for erosion control and productivity improvement in the black soil region. Full article

The xeno-fungusphere, a novel microbial ecosystem formed by integrating exogenous fungi, indigenous soil microbiota, and electroactive microorganisms within microbial fuel cells (MFCs), offers a transformative approach for agricultural remediation and medicinal plant conservation. By leveraging fungal enzymatic versatility (e.g., laccases, cytochrome P450s) and conductive hyphae, this system achieves dual benefits. First, it enables efficient degradation of recalcitrant agrochemicals, such as haloxyfop-P, with a removal efficiency of 97.9% (vs. 72.4% by fungi alone) and a 27.6% reduction in activation energy. This is driven by a bioelectric field (0.2–0.5 V/cm), which enhances enzymatic activity and accelerates electron transfer. Second, it generates bioelectricity, up to 9.3 μW/cm², demonstrating real-world applicability. In medicinal plant soils, xeno-fungusphere MFCs restore soil health by stabilizing the pH, enriching dehydrogenase activity, and promoting nutrient cycling, thereby mitigating agrochemical-induced inhibition of secondary metabolite synthesis (e.g., ginsenosides, taxol). Field trials show 97.9% herbicide removal in 60 days, outperforming conventional methods. Innovations, such as adaptive electrodes, engineered strains, and phytoremediation-integrated systems, have been used to address soil and fungal limitations. This technology bridges sustainable agriculture and bioenergy recovery, offering the dual benefits of soil detoxification and enhanced crop quality. Future IoT-enabled monitoring and circular economy integration promise scalable, precision-based applications for global agroecological resilience. Full article

Excess phosphorus (P) and nitrogen (N) in wastewater contribute to eutrophication, driving the need for low–cost and sustainable recovery technologies. This study presents a novel adsorbent synthesized from spent coffee grounds biochar (CB) chemically modified with Mn²⁺/Zn²⁺/Fe³⁺ (oxy)hydroxide nanoparticles (CB–M) for simultaneous removal of phosphate and ammonium. Batch adsorption experiments using both synthetic solution and municipal wastewater were conducted to evaluate the material’s adsorption performance and practical applicability. Kinetic, isotherm, thermodynamic, and sequential extraction analyses revealed that CB–M achieved maximum phosphate adsorption capacities ranging from 42.6 to 72.0 mg PO₄³⁻·g⁻¹ across temperatures of 20–33 °C, reducing effluent phosphate concentrations to below 0.01 mg·L⁻¹. Ammonium removal was moderate, with capacities ranging between 2.8 and 2.95 mg NH₄⁺·g⁻¹. Thermodynamic analysis indicated that phosphate adsorption was spontaneous and endothermic, dominated by inner–sphere complexation, while ammonium uptake occurred primarily through weaker, reversible ion exchange mechanisms. Sequential extraction showed over 70% of adsorbed phosphate was associated with Fe-Mn-Zn phases, indicating the potential for use as a slow–release fertilizer. The CB–M retained structural integrity and exhibited partial desorption, supporting its reusability for nutrient recovery. Compared to other biochars, CB–M demonstrated superior phosphate selectivity at a neutral–pH, avoided the use of hazardous metals, and transformed coffee waste into a multifunctional material for wastewater treatment and soil amendment. These findings underscore the potential of CB–M as a circular economy solution for nutrient recovery without introducing secondary contamination. Full article

Elevated phosphorus levels in aquatic ecosystems have been identified as a critical driver of eutrophication processes, necessitating resource-recovery remediation strategies. Adsorption techniques show particular promise for nutrient recovery due to their selective binding capacities and operational feasibility. In this study, the Mg- and Ca-modified biogas residue-based biochar (Ca-Mg/BC) was successfully prepared via a “bimetallic loading-pyrolysis” modification strategy. The optimum temperature for the calcination of the material and the salt solution impregnation concentrations were determined experimentally through optimization of the synthesis conditions. Structural and chemical analyses of Ca–Mg/BC demonstrated that the material contains MgO and CaO. The specific surface area of Ca–Mg/BC was 8.49 times higher than that of the unmodified biochar (BC). The optimized Ca–Mg/BC achieved 95% phosphate removal rate (157.13 mg/g adsorption capacity). FTIR and XPS characterization results indicated the importance of Ca/Mg loading in phosphate capture. MgO and CaO were mainly loaded on the surface of the material and adsorbed phosphate through a chemical reaction. Crucially, the phosphate-laden biochar exhibited potential as a nutrient-enriched soil amendment, opening the material loop from wastewater treatment to agricultural applications. This sustainable strategy simultaneously addresses water pollution control and sustainable development, providing environmentally benign solutions compatible with industrial effluent treatment and sustainable agriculture practices. Full article

Coastal wetlands provide vital ecosystem services, yet large-scale removal of invasive Spartina alterniflora disrupts soil carbon pools and fragments habitats. Converting this biomass to biochar may enhance restoration outcomes, though ecological effects remain poorly understood. We evaluated how Spartina alterniflora-derived biochar (0%, 0.5%, 1%, and 3%) influences growth performance, clonal reproduction, root morphology, and rhizosphere properties of native Scirpus mariqueter. Moderate biochar addition (1%) significantly boosted plant performance, increasing total biomass by 64.5%, aboveground biomass by 36.7%, and belowground biomass by 115.0%, while root length increased by 135.8%. Biochar improved soil moisture and nutrient availability, including nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and available phosphorus (AP), while stimulating nitrification and promoting clonal propagation. In contrast, high-dose biochar (3%) elevated soil salinity and electrical conductivity, leading to suppressed plant growth and reproductive allocation. Correlation analysis revealed strong positive associations between root volume and soil nutrient levels. Our findings demonstrate that moderate application of Spartina alterniflora-derived biochar enhances plant productivity and soil function, potentially improving carbon sequestration in restored coastal wetlands. This study provides insights into ecological recycling of invasive biomass and supports biochar as a viable tool for sustainable wetland restoration, though potential risks at high concentrations warrant further investigation. Full article