Search Results (1,384)

The soil microbial functional community is a better predictor of ecosystem processes under global change. However, the responses of the soil microbial functional community structure to short-term nitrogen (N) and phosphorus (P) additions remain unclear. Here, we carried out an experiment exploring the effects of N and P additions on soil fungal and bacterial functional diversity and community composition in an alpine steppe on the Tibetan Plateau. The results showed that soil fungal functional α-diversity significantly decreased under N or P addition, whereas soil bacterial functional α-diversity did not change. Furthermore, soil bacterial functional group aerobic nitrite oxidation increased significantly under combined N and P additions, but soil bacterial and fungal community composition and β-diversity did not change. Further analysis illustrated that soil available nitrogen was the main factor leading to the changes in soil fungal functional α-diversity and soil bacterial functional groups under N and P additions. Therefore, we should give importance to the potential influence in view of future increasing N and P deposition on the soil microbial functional community in the alpine grassland on the Tibetan Plateau, which will be beneficial for the prediction of soil biogeochemical cycles and guiding ecosystem management. Full article

This study aimed to investigate the effects of different nitrogen (N) fertilizer rates and sowing dates on grain yield, protein content, grain N uptake, and nitrogen recovery efficiency (NRE) in spring and facultative wheat (Triticum aestivum L.) cultivated in northwestern and central Romania from 2018 to 2020. The experiment was designed as a split–split plot study with two spring sowing dates (SDs): an optimal date (1–15 March) and a delayed date (postponed by two weeks). All treatments received a basal autumn fertilizer supplying 36 kg N ha⁻¹ and 92 kg P ha⁻¹. In spring, three N treatments were evaluated: no additional N (N₃₆), 72 kg N ha⁻¹ (N₁₀₈), and 105 kg N ha⁻¹ (N₁₄₁), with the supplementary N top-dressed at the booting stage. The results showed that delayed sowing significantly altered grain N uptake dynamics and reduced NRE, even under standard fertilization regimes. Specifically, delayed sowing reduced grain yield by 7.52% to 28.39% compared to optimal sowing, while adverse climatic interactions in delayed setups reduced the mean NRE to as low as 16.43%. These findings indicate that conventional N application strategies may be suboptimal under variable sowing conditions and highlight the importance of adaptive N management to improve both agronomic performance and environmental sustainability. Full article

Winter fallow fields are widely distributed in southern China, where legume–grass mixtures are considered a useful approach for improving land-use efficiency and forage productivity while maintaining agroecosystem functions. Previous studies on the use of winter fallow fields have generally focused either on monoculture or on crops subjected to a single cut. These studies have primarily assessed aboveground productivity, whereas soil bacterial community responses have received comparatively little attention. Consequently, limited information is available on how different seeding combinations and cutting times affect aboveground biomass and soil bacterial community structure in mixed-cropping systems. A fixed-site field experiment involving annual ryegrass (Lolium multiflorum L.) and Chinese milk vetch (Astragalus sinicus L.) was conducted on yellow clay soil. Five annual ryegrass-Chinese milk vetch seeding combinations (100:0, 75:25, 50:50, 25:75, and 0:100) were established as proportions of their respective monoculture seeding rates. The same plots were maintained for five consecutive winter growing seasons, from autumn 2021 to spring 2026. Plant and soil samples were collected only during the final growing season (2025–2026), at four cutting times in January, March, April, and May. These samples were used to assess the effects of seeding combination and cutting time on forage productivity, root traits, soil fertility, and soil bacterial community structure. Among all groups, the 75% annual ryegrass + 25% Chinese milk vetch group (R75M25) exhibited the best overall performance, with cumulative yields after four cuttings of 17,274.21 kg·ha⁻¹ dry matter, 2717.02 kg·ha⁻¹ crude protein, and 12,220.46 kg·ha⁻¹ digestible dry matter. In addition, the R75M25 group maintained relatively high contents of alkali-hydrolyzable nitrogen, available phosphorus, and available potassium in soil. The top three phyla of soil samples were Proteobacteria, Actinobacteria, and Acidobacteria, with a total relative abundance of >60%. Among these, Proteobacteria showed the greatest relative abundance in monoculture, whereas the seeding combination had a reduced proportion of it. In addition, its relative abundance rose steadily with cutting time. At the genus level, RB41, Gemmatimonas, and Sphingomonas dominated the soil bacterial community. The seeding combinations did not alter soil bacterial alpha diversity. Cutting times significantly reduced the phylogenetic diversity index and drove the temporal differentiation of taxa such as Actinobacteria and Bacteroidetes. The inclusion of an appropriate proportion of Chinese milk vetch improved forage nutritional value while maintaining high biomass accumulation in southern China, with the R75M25 group showing the best overall performance in winter fallow fields. Full article

This study investigates the effects of magnesium carbonate (MgCO₃) nanoparticles in addition to cottonseed biodiesel/diesel blends on diesel engine performance and emission characteristics. Experiments were conducted under various engine loads, and Response Surface Methodology (RSM) was employed for modeling and multi-objective optimization of operating parameters. Results showed that biodiesel blends increased brake-specific fuel consumption (BSFC) by up to 16.11% and reduced brake thermal efficiency (BTE) by up to 13.53% compared to diesel fuel, mainly due to lower calorific value and higher viscosity. However, the addition of MgCO₃ nanoparticles improved combustion performance, reducing BSFC by up to 5.25% and increasing BTE by up to 5.87% under optimal conditions. Emission analysis revealed that nitrogen oxide (NO_x) emissions increased by up to 49.06%, while hydrocarbon (HC) and carbon monoxide (CO) emissions decreased by up to 42.44% and 51.93%, respectively, indicating enhanced combustion efficiency. Carbon dioxide (CO₂) emissions increased by up to 17.67% due to improved oxidation reactions. RSM analysis confirmed the statistical significance of the developed models with high coefficients of determination (R² = 0.9178–0.9921). The optimal operating condition was determined to be 52.30 ppm MgCO₃ and 1.51 kW engine load. Validation experiments showed good agreement between predicted and experimental results, with errors ranging from 0.71% to 8.83%, all within acceptable limits. Overall, the study demonstrates that MgCO₃ nanoparticles can partially mitigate the performance drawbacks of biodiesel while improving combustion quality, and RSM is an effective tool for optimizing engine operating conditions. Full article

Acidic soil stress can limit sunflower productivity by reducing nutrient availability, impairing root development, and affecting early plant establishment, while foliar nutrient application and seed pretreatment may provide additional support under recommended nitrogen fertilization. This study evaluated the potential of selected nutrient-based products to mitigate acidic environment stress in sunflower through a field experiment and a complementary laboratory germination test. The field experiment was conducted in 2025 at Ivankovo, Croatia, on acidic soil (pH KCl 4.47), under a recommended nitrogen fertilization dose of 85 kg N/ha for sunflower production. Foliar treatments included Barrier, Bioplex, Borealg, and Bor-feed, while the control was left without additional foliar treatment. Seed yield, yield components, seed oil and protein content, and oil and protein yield were determined. In parallel, sunflower seeds were pretreated with the same products and germinated under controlled conditions in aqueous solutions with pH values ranging from 3.5 to 8.5. Germination, seedling morphology, fresh biomass, total phenolic content, antioxidant activity, and free proline content were analysed. Under field conditions, foliar treatments significantly affected plant height, head diameter, seed mass per head, seed oil and protein content, and seed yield. Barrier produced the highest seed yield (5.3 t/ha), oil yield (2.8 t/ha), and protein yield (0.8 t/ha), whereas Bor-feed had the highest seed oil content (54.36%) but the lowest seed yield (2.5 t/ha). In the laboratory experiment, average total germination was 92%, with maximum values of 96–97% depending on treatment and pH. Barrier most strongly promoted root, shoot, and total seedling length, while Borealg increased root, shoot, and total fresh mass. Biochemical responses depended on seed pretreatment and pH, with the highest antioxidant activity recorded in Bioplex at pH 7.5 and higher proline accumulation generally observed in untreated seedlings. The highest antioxidant activity was recorded in Bioplex seed pretreatment at pH 7.5 (5.34 mM Fe(II)/g FW), while the highest free proline content was observed in the control at pH 5.5 (7.87 mM/g FW) and pH 3.5 (7.79 mM/g FW), indicating a stronger stress response in untreated seedlings. The present study indicates that selected foliar products and seed pretreatments may support sunflower productivity and early growth under acidic stress conditions, with Barrier showing the most consistent positive response. Full article

Silicon, as a crucial element of plants, contributes to plants’ resistance to biotic stresses like herbivore feeding. In tropical and subtropical Asia, the apple snail (Ampullariidae) is an invasive aquatic herbivorous snail in agricultural and wetland ecosystems, like paddy fields, which suffer from heavy nitrogen eutrophication. However, little is known about the potential effects of supplementing rice leaves treated with silicon and nitrogen on the feeding metrics of apple snails (Pomacea spp.). This study conducted a greenhouse experiment to examine the effects of silicon and nitrogen addition on rice seedlings grazed by apple snails, with two levels of silicon addition (0 and 1.5 mM) and three levels of nitrogen addition (0.72, 1.44 and 5.76 mM). The results showed that silicon addition increased plant mass under low and high nitrogen addition, and increased the C/N ratio and tannin content only under the middle nitrogen addition, while it increased the leaf sulfur content of rice at all three levels of nitrogen addition. However, silicon addition significantly decreased the growth of apple snails while significantly increasing flavonoid content and the force of fracture of rice leaves across all nitrogen levels. This study indicates that silicon addition could improve the defense of rice against herbivory by invasive apple snails, providing insights into the protection of wetland crops in the context of eutrophication and biological invasion. Full article

The application of biochar and magnesium (Mg) fertilizer can alleviate acidification, improve soil fertility, and enhance tea quality. However, the effects of different biochar application rates on soil properties, tea photosynthesis, and quality remain unclear. To elucidate their effects, a 90-day pot experiment was conducted with nine treatments: conventional fertilization (CK), improved conventional fertilization (CF), Mg fertilizer (MF), low/medium/high biochar (LBCF, MBCF, HBCF), and their combination with Mg (LBMF, MBMF, HBMF) in a controlled growth chamber, and soil properties, tea plant photosynthesis, and tea quality were measured. The results showed that higher application rates of biochar with Mg significantly alleviated soil acidification, increasing pH by 0.20–0.24 units. HBMF significantly enhanced key soil nutrients: total carbon (+198.11%), total nitrogen (+116.43%), and ammonium nitrogen (+73.89%). Ex-Mg increased with Mg addition and was further promoted by biochar, and photosynthetic rates increased by 71.69–101.41% in biochar and Mg application. These improvements increased free amino acids, caffeine, and soluble sugars in tea leaves by 39.56%, 46.88%, and 30.79% respectively under HBMF. Additionally, the relative contents of alcohols and esters increased by 93.29% and 62.20%, with marked rises in linalool and methyl salicylate. The increased tea quality is linked to higher activities of β-glucosidase and lipoxygenase observed in HBMF. In conclusion, the combined application of high biochar (2% of soil weight) and Mg fertilizer (15% of fertilizer weight) effectively improved soil quality, enhanced photosynthesis, and ultimately elevated both the taste and aroma quality of tea. Full article

Understanding the relationship between biodiversity and ecosystem multifunctionality remains a central challenge in ecology. Although biodiversity is generally associated with enhanced multifunctionality, this relationship can vary across ecosystems and environmental contexts. It remains unclear how concurrent global changes, such as drought and nitrogen deposition, modulate biodiversity–multifunctionality relationships, in particular the moso bamboo forests in subtropical China. We conducted a field manipulation experiment combining throughfall reduction and nitrogen addition to simulate drought and nitrogen deposition, and applied amplicon sequencing to examine how these global change factors independently and interactively influence soil microbial diversity, multifunctionality, and their interrelationships. We found that throughfall reduction significantly reduced soil multifunctionality, likely due to lower soil water availability, and nitrogen addition exacerbated this negative effect. However, environmental changes did not affect bacterial and fungal α-diversity, nor was soil multifunctionality correlated with microbial diversity. Instead, shifts in soil multifunctionality were closely linked to changes in microbial community composition and co-occurrence network structure. In particular, increasing relative abundances of Acidobacteriota, Myxococcota, and Chytridiomycota were positively associated with higher soil multifunctionality. Our findings demonstrate that soil multifunctionality responses to throughfall reduction and nitrogen addition are primarily mediated through microbial community reorganization rather than diversity loss, providing new insights into the mechanisms linking global change drivers, microbial communities, and ecosystem functioning. Full article

Baijiu brewing generates large quantities of wastewater sludge, which presents major disposal challenges but contains abundant organic matter and nutrients, indicating great potential as a soil amendment. This study investigated the soil amendment effects of granulated and coated Baijiu brewing sludge through a 112-day soil column leaching experiment. Sludge particles were coated with sodium alginate (SA), polyvinyl alcohol (PVA), and ester gum (EG), and compared with untreated air-dried sludge (CK₁), uncoated granulated sludge (CK₂), compound fertilizer (F), and a blank control (B). The results showed that coated sludge treatments significantly increased soil leachate pH, total organic carbon, total nitrogen, total phosphorus, and total potassium, and exhibited obvious controlled-release effects on nitrogen, phosphorus, and potassium nutrients compared with uncoated sludge. Soil enzyme analysis indicated that SA treatment increased catalase activity, acid phosphatase activity was generally enhanced by sludge addition, and urease activity was reduced in coated sludge treatments. FTIR and BET analysis showed that both coated and uncoated sludge increased soil-specific surface area and changed soil pore structure. These findings confirm that granulated and coated Baijiu brewing sludge can be used as an effective slow-release soil amendment, and sodium alginate coating shows the most comprehensive improvement in multiple soil health indicators, with high application value for resource utilization of Baijiu sludge and soil quality improvement. Full article

To explore low-carbon spring wheat production strategies for the ecologically fragile Qinghai Plateau, a two-year field experiment was conducted using a split-plot design. The main plots were set with three nitrogen (N) application levels: N0 (0 kg·ha⁻¹, no N input), N1 (157.5 kg·ha⁻¹, 30% N reduction relative to conventional rate), and N2 (225 kg·ha⁻¹, the conventional rate). The subplots comprised four green manure mixed cropping patterns: sole cropped common vetch (CK), common vetch mixed with hull-less barley (HB), common vetch mixed with hairy vetch (HV), and common vetch mixed with rapeseed (RS). Averaged across green manure treatments, N1 reduced global warming potential (GWP) by 14.56% and greenhouse gas intensity (GHGI) by 16.89% compared with N2. Under the N1 treatment, compared with CK, RS reduced cumulative CO₂ emissions by 7.77% and GWP by 7.45%, maintained wheat grain yield comparable to those under N2, and obtained the minimum GHGI which was 2.92% lower than CK. Regarding soil properties, all green manure patterns significantly increased soil available phosphorus (AP) and available potassium (AK) compared with CK. Specifically, HB increased AP by 12.81% and AK by 16.38%, and RS also increased AP by 4.37% and AK by 2.36%. In addition, HB enhanced soil organic matter (SOM) by 5.85%, ammonium nitrogen (NH₄–N) by 8.13%, and nitrate nitrogen (NO₃–N) by 4.34%. Soil NH₄–N and NO₃–N were identified as key drivers of GHGI across treatments. On the Qinghai–Tibet Plateau, a 30% N reduction combined with target-oriented green manure mixtures—RS for emission mitigation and HB for high yield and fertility—offers a viable low-carbon strategy for spring wheat production. Full article

The co-contamination of manganese ions (Mn²⁺) and ammonia nitrogen (NH₄⁺) caused by the stockpiling of manganese residue poses a serious threat to the ecological environment. In this study, a series of the composite was prepared from red mud, bentonite, and corn straw via oxygen-limited pyrolysis. The effects of pyrolysis temperature and raw material ratio on the material properties were investigated, and the synergistic remediation performance of the composites for Mn²⁺ and NH₄⁺ in manganese residue-contaminated soil was evaluated through a 180-day soil column experiment. The results showed that the composite prepared with a raw material ratio of 1:1:1 at a pyrolysis temperature of 700 °C exhibited the largest specific surface area and the most developed pore structure, achieving a Mn²⁺ removal rate of 92.72% ± 0.85% in aqueous solution. In the soil column experiment, the material prepared at 700 °C gave the highest immobilization rate for soil Mn²⁺ (96.22% ± 0.5%), whereas the combined addition of materials prepared at 700 °C and 500 °C achieved the best removal efficiency for NH₄⁺ (99.33% ± 0.23%). Mechanistic studies revealed that the stabilization of Mn²⁺ is primarily attributable to alkaline precipitation and mineral lattice solid solution induced by the composite, leading to the formation of stable spinel phases (e.g., (Fe,Mn)₃O₄) and insoluble manganese phosphate-carbonate salts. The removal of NH₄⁺ is proposed to proceed via adsorptive enrichment by the porous structure and Fe⁰-mediated Fenton-like catalytic oxidation, ultimately converting NH₄⁺ to N₂ gas. The 180-day monitoring results demonstrated that the remediation effect continuously increased over time, indicating good long-term stability of the composite. This study provides an efficient, low-cost functional material derived from solid waste for the remediation of manganese residue-contaminated soil and offers a theoretical basis for the synergistic resource utilization of multiple solid wastes. Full article

To develop green feed additives suitable for antibiotic-free livestock farming on the Qinghai–Tibet Plateau, this study used Lactobacillus salivarius TB2.1, isolated from Tibetan black pigs, and Lactobacillus agilis CW13.2, isolated from wild boars in the Changbai Mountains, to prepare fermented feed. The study investigated the effects of these additives on the growth performance, slaughter performance, meat quality, immune and antioxidant functions, and gut microbiota composition of Duroc × Landrace × Large White crossbred finishing pigs (DLY finishing pigs). The experiment included 72 finishing pigs with an average body weight of 54.07 ± 1.02 kg, which were randomly divided into three groups, each with four replicates of 6 pigs. The control group (CK) was fed a basal diet, one treatment group (TB) was fed a diet consisting of 50% basal diet plus 50% Lactobacillus salivarius TB2.1-fermented feed, and the other treatment group (CW) was fed a diet consisting of 50% basal diet plus 50% Lactobacillus agilis CW13.2-fermented feed. The pre-feeding period lasted 3 days, and the experimental period lasted 57 days. The results showed that, compared with the CK group, (1) the CW and TB groups had significantly higher levels of crude protein, lactic acid, acetic acid, and propionic acid in the feed (p < 0.05), and significantly lower levels of crude fiber, neutral detergent fiber, acid detergent fiber, ammonium nitrogen, and pH (p < 0.05); (2) in the CW and TB groups, final body weight, average daily weight gain, and average daily feed intake were significantly higher (p < 0.001), while the feed-to-gain ratio was significantly lower (p < 0.01), with the CW group performing better than the TB group; (3) in both the CW and TB groups, carcass weight, eye muscle area, and meat redness significantly increased (p < 0.001), while backfat thickness and shear force significantly decreased (p < 0.001); (4) in both the CW and TB groups, serum immunoglobulin G, interleukin-2, and superoxide dismutase levels significantly increased (p < 0.05), malondialdehyde levels were significantly reduced in the CW group (p < 0.05), and catalase activity was significantly increased in the TB group (p < 0.05); (5) the relative abundance of Escherichia spp. in the cecum was significantly reduced in both the CW and TB groups (p < 0.05), while beneficial bacteria such as Lactobacillus spp. were significantly enriched (p < 0.05). In summary, feed fermented with Lactobacillus salivarius TB2.1 and Lactobacillus agilis CW13.2 can effectively improve the production performance of finishing pigs, enhance meat quality, strengthen immune and antioxidant capacities, and optimize the gut microbiota structure. Among these, CW13.2 was more effective in promoting weight gain, while TB2.1 was more effective in regulating protein and lipid metabolism. Fermented feed produced with both strains shows promising application prospects and can provide high-quality microbial strains and technical support for antibiotic-free swine farming on the Qinghai–Tibet Plateau. Full article

For many countries, the reclamation of coastal saline–alkali land is of great significance for ensuring food security. However, systematic research on the effects of leaching irrigation and biochar application on the “soil–crop” system in coastal areas remains scarce. This study investigated the effects of three irrigation quotas (8, 16, and 24 mm per application, applied once every 10 days) and four biochar rates (0, 3, 5, 7 t·ha⁻¹, from composite biomass) on soil salinity, available nutrients, and yield and quality of sunflower in coastal saline–alkali soils of Jiangsu, China. The experiment used a completely randomized block design with three replications. The results showed that soil salinity under all treatments exhibited a consistent decline–rebound–decline pattern over the growing season, with the lowest values occurring around 55 days after sowing and peaking around 95 days. The combined application of water and biochar enhanced salt reduction, with the highest irrigation and biochar levels achieving the greatest desalination effect. Biochar application increased soil available phosphorus and potassium contents, with average increases of 19.6% and 13.3% under the highest biochar rate compared with the control, while available nitrogen showed no clear response to any treatment. Crop yield responded nonlinearly to water and biochar inputs: under low irrigation, yield increased continuously with biochar addition, whereas under medium or high irrigation, yield plateaued at the moderate biochar rate (5 t·ha⁻¹), with no further gains from additional biochar or water. Regarding seed quality, linoleic acid content generally increased with higher water and biochar levels, oleic acid decreased, and crude fat remained unaffected. Based on a balanced consideration of yield, quality, salt reduction, and water conservation, the combination of 16 mm irrigation per application and 5 t·ha⁻¹ biochar is recommended as the optimal amelioration strategy for coastal saline–alkali land. Full article

Decarbonization of district heating (DH) systems requires practical solutions that can reduce greenhouse-gas (GHG) emissions while utilizing existing infrastructure. Therefore, the study experimentally evaluates hydrogen–methane-based gas co-combustion in a real urban DH installation in Riga, Latvia, using a 6.3 MW hot-water boiler operating under commercial conditions without equipment modification. Experiments were conducted under steady-state operating conditions by blending hydrogen with the baseline methane-based gas at volumetric fractions of 0%, 10%, and 20%. Thermal performance and emissions (CO₂, NO_x, and CO) were monitored during 30 min measurement periods, and three independent experiments were performed for each hydrogen blending level. The experimental data were analyzed using one-way analysis of variance (ANOVA) to evaluate the statistical significance of the observed changes. Stable ignition, flame anchoring, and load-following performance were maintained under all investigated conditions, and no flashback or blow-off events occurred. Boiler efficiency remained essentially constant at approximately 92% (92.1–91.9%), while thermal output was maintained at 6.3 MW. When CO₂ emissions were normalized to useful thermal energy output (kg CO₂/MWh), the specific CO₂ emission intensity decreased from 202 kg/MWh for pure methane-based gas operation to 161 kg/MWh at 20 vol.% hydrogen addition, corresponding to an approximately 20% reduction in the carbon intensity of delivered heat under the investigated operating conditions. Carbon monoxide (CO) emissions remained low (~6–7 mg/kWh) and particulate matter concentrations remained below 1 mg/m³. Nitrogen oxide emissions increased moderately from approximately 40 mg/kWh to 52 mg/kWh due to enhanced combustion temperatures but remained within applicable regulatory limits. No degradation of safety systems, fuel metering equipment, or infrastructure and no leakage events were observed during the experiments. The results demonstrate that hydrogen blending up to 20 vol.% can achieve substantial reductions in the carbon intensity of heat generation while preserving boiler performance and operational safety, confirming hydrogen co-combustion as a practical transitional decarbonization pathway for existing DH systems. They also uncover the potential of hydrogen blending to support the sustainable decarbonization of DH systems by reducing GHG emissions while preserving existing infrastructure and operational reliability. Full article

Reclaimed soil is an important reserve land resource, and improving its water and nitrogen retention was essential for sustainable agriculture. In this study, corn straw biochar (BC) and biochars modified with H₃PO₄ (HBC) and NaOH (NBC) were applied to reclaimed yellow-cinnamon soil from southern Henan at rates of 1%, 2%, and 4%. Soil column experiments and simulations were conducted to investigate their effects on soil water movement and the leaching of NH₄⁺-N and NO₃⁻-N. The results showed that all biochar treatments significantly delayed wetting front migration, reduced cumulative infiltration and saturated hydraulic conductivity (K_sat), and increased soil water content and retention. The overall effectiveness followed HBC > NBC > BC. Compared with the control (CK), HBC prolonged the time for the wetting front to reach 50 cm by 19.25–43.92% and reduced the 180-min cumulative infiltration by 10.97–27.72%. At the 4% addition rate, water retention was increased by 15.84%, 11.85%, and 7.30%, and K_sat was decreased by 30.74%, 28.14%, and 18.18% for HBC, NBC, and BC, respectively. NH₄⁺-N leaching was significantly reduced by all biochar treatments, with the maximum reduction (57.13%) achieved under 4% NBC. However, NO₃⁻-N leaching from the biochar-amended soils was generally higher than that from CK, except for the 4% NBC treatment during the 10–20 h period. In conclusion, the biochars effectively improved soil water retention and reduced NH₄⁺-N leaching but had limited effect on NO₃⁻-N control. Further investigation into the mechanisms is needed. Full article