Search Results (1,145)

Organic manure and grass mulching are widely recognized as modifiers of soil microbial communities and nutrient dynamics; however, the combined effects of these practices on nitrogen fractionation and microbial functionality in orchard ecosystems remain poorly understood. This study conducted a comprehensive evaluation of soil nitrogen fractions, enzymatic activity, microbial diversity and functional traits in walnut orchards under three management practices: organic manure (OM), grass mulching combined with manure (GM), and chemical fertilization (CF) in China’s Loess Plateau. The results revealed that OM and GM significantly enhanced soil nutrient pools, with GM elevating total nitrogen by 1.96-fold, soil organic carbon by 97.79%, ammonium nitrogen by 128%, and nitrate nitrogen by 54.56% relative to CF. Furthermore, the OM significantly increased the contents of total hydrolysable nitrogen, amino sugar nitrogen, amino acid nitrogen, ammonia nitrogen, hydrolysable unidentified nitrogen, non-acid-hydrolyzable nitrogen compared to the CF and GM treatments. Meanwhile, ASN and AN had significant effects on mineral and total nitrogen. The OM and GM had higher activities of leucine aminopeptidase enzymes (LAP), α-glucosidase enzyme, β-glucosidase enzyme (βG), and N-acetyl-β-D-glucosidase enzyme (NAG). Microbial community analysis revealed distinct responses to different treatments: OM and GM enhanced bacterial Shannon index, while suppressing fungal diversity, promoting the relative abundance of copiotrophic bacterial phyla such as Proteobacteria and Chloroflexi. Moreover, GM favored the enrichment of lignocellulose-degrading Ascomycota fungi. Functional annotation indicated that Chemoheterotrophy (43.54%) and Aerobic chemoheterotrophy (42.09%) were the dominant bacterial metabolic pathways. The OM significantly enhanced the abundance of fermentation-related genes. Additionally, fungal communities under the OM and GM showed an increased relative abundance of saprotrophic taxa, and a decrease in the relative abundances of potential animal and plant pathogenic taxa. The Random forest model further confirmed that βG, LAP, and NAG, as well as Basidiomycota, Mortierellomycota, and Ascomycota served as pivotal mediators of soil organic nitrogen fraction. Our findings demonstrated that combined organic amendments and grass mulching can enhance soil N retention capacity, microbial functional redundancy, and ecosystem stability in semi-arid orchards. These insights support the implementation of integrated organic management as a sustainable approach to enhance nutrient cycling and minimize environmental trade-offs in perennial fruit production systems. Full article

In response to China’s drive to bring newly cultivated land into production, this study evaluated how combined organic fertilizer and microbial inoculants affect soil quality, bacterial community structure, and maize yield. Four treatments were evaluated: FC (chemical fertilizer only), T50 (50% organic fertilizer + 50% chemical fertilizer), T50M (T50 plus microbial inoculant), and CK (no fertilizer). T50M significantly increased yield compared to FC and CK (p < 0.05), achieving the highest yield of 6995.73 kg ha⁻¹. This was 20.09% greater than FC. Community composition analyses showed that soil in newly cultivated land was dominated by Blastocatellia, Vicinamibacteria, and Alphaproteobacteria, together accounting for over 35.7% of total bacterial abundance. Redundancy analysis at the class level explained 55.7% of variance; soil organic matter (SOM) and available potassium positively correlated with Alphaproteobacteria and Bacteroidia, while available phosphorus and nitrate nitrogen aligned with Actinobacteria and Bacilli. Path analysis indicated that SOM and total nitrogen were the strongest positive drivers of yield. Actinobacteria and Acidobacteriae also showed direct positive effects, whereas Verrucomicrobiae had a negative effect. These results demonstrate that integrated organic–microbial amendments can enhance soil fertility and alter microbial diversity toward taxa that can improve maize productivity. Full article

Reducing nitrogen (N) fertilizer input while sustaining maize yield and alleviating nitrogen leaching is a significant challenge due to economic and practical feasibility, as well as the environmental friendliness of this process. However, it remains unclear whether reducing nitrogen by using a blend of slow/controlled-release nitrogen fertilizer (SCRNF) with urea at an equal nitrogen rate can achieve the desired yield and mitigate nitrogen leaching. A field experiment consisting of four treatments (240 kg·N·hm⁻², 100% urea, CK; 240 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF, N100%; 192 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF under 20% N reduction, NR20%; 144 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF under 40% N reduction, NR40%) was conducted in Shanxi from 2019 to 2021. In this study, we explored the effects of a mixture of SCRNF and urea on grain yield, yield components, main agronomic traits, nitrogen partial factor productivity, and content of nitrate/ammonium nitrogen in soil in maize under decreasing amounts of nitrogen fertilization. The results showed that the mixture of SCRNF and urea can improve spring maize yield under reduced nitrogen input, with its yield and yield component factors generally performing better than those of the control. The yield of the NR20% treatment was highest in 2020 and 2021, increasing by 8.8% and 11.7% over CK, respectively; the NR20% and NR40% treatments had no significant impact on the main agronomic traits of spring maize, such as plant height, leaf area, shoot biomass, and SPAD value of the ear leaf, compared with CK; the NR20% and NR40% treatments significantly (p < 0.05) enhanced nitrogen partial factor productivity but reduced nitrate and ammonium nitrogen in 0~200 cm soil over the three years compared with CK. Therefore, reducing nitrogen input by 20% with 50% N from urea and 50% N from biodegradable film-coated urea was an appropriate nitrogen fertilizer management measure for mitigating environmental risks without compromising maize yield in North China. Full article

Morchella spp. is a type of valuable and rare edible fungi cultivated in soil. Optimization of the cultivation medium for Morchella spp. is key to obtaining high-efficiency production in an ecologically friendly manner. Recently, the sustainable resource utilization of agricultural waste has gathered attention. Specifically, reusing tomato substrate, mushroom residues, and coconut shells can lower the production costs and reduce environmental pollution, demonstrating remarkable ecological and economic benefits. To determine the soil microbial communities of Morchella spp. using different culture medias and influencing factors, this study analysed the relative abundance of bacterial and fungal communities in natural soil, soil with 5% tomato substrate, soil with 5% mushroom residues, and soil with 5% coconut shells using Illumina NovaSeq high-throughput sequencing. In addition, intergroup differences, soil physiochemical properties, and product quality were also determined. Results demonstrated that agricultural waste consisting of mushroom residues, waste tomato substrate, and coconut shells can improve the efficiency of Morchella spp. cultivation. When considering yield and quality, mushroom residue achieved the highest yield (soil nutrient enrichment), followed by tomato substrate (water holding + grass carbon nutrient). All three types of agricultural waste promoted early fruiting, significantly increased polysaccharide, crude protein, and potassium content, and lowered crude fat and fibre. In regard to soil improvement, the addition of different materials optimized the soil’s physical structure (reducing volume weight and increasing water holding capacity) and chemical properties (enrichment of nitrogen, phosphorus, and potassium, regulating nitrogen and medium trace elements). For microbial regulation, the added materials significantly increased the abundance of beneficial bacteria (e.g., Actinomycetota, Gemmatimonadota and Devosia) and strengthened nitrogen’s fixation/nitration/decomposition functions. In the mushroom residue group, the abundance of Bacillaceae was positively related to yield. Moreover, it inhibited pathogenic fungi like Mortierella and Trichoderma, and lowered fungal diversity to decrease ecological competition. In summary, mushroom residues have nutrient releasing and microbial regulation advantages, while tomato substrate and coconut shells are new high-efficiency resources. These increase yield through the “physiochemical–microorganism” collaborative path. Future applications may include regulating the function of microorganisms and optimizing waste preprocessing technologies to achieve sustainability. Full article

Horticultural research into the group of plants known as cycads has been deficient, and this includes the study of root growth and function. The form of nitrogen (N) available to plants is known to influence root growth and morphology. The response of cycad roots to N has not been studied to date. Cycas revoluta and Cycas edentata seedlings were grown in hydroponic culture and provided urea, nitrate, or ammonium forms of N. Solutions with all three forms of N increased root growth and branching when compared with nutrient solution devoid of N, with ammonium eliciting the greatest increases. Ammonium increased lateral root length 210% for C. revoluta and 164% for C. edentata. Ammonium decreased specific root length 38% for C. revoluta and 39% for C. edentata. The influence of the N source on stem and leaf growth was minimal. Ammonium increased the root-to-shoot ratio 15% for C. revoluta and 51% for C. edentata, but urea and nitrate did not influence this plant trait. A mixture of nitrate and ammonium generated plant responses that were no different from ammonium alone. The plants supplied with N in the solution produced coralloid root growth that was 14% of the no-N plants for C. revoluta and 22% of the no-N plants for C. edentata. This initial determination of the cycad plant response to the N form indicated that root plasticity was considerable and ammonium stimulated root growth more so than urea or nitrate. Long-term growth studies in mineral soils and nursery container medium are needed to determine if these findings from the hydroponic culture of small seedlings translate to general recommendations for the preferential use of ammonium for cycad culture. Full article

Restoring vegetation in riparian zones is regarded as a best management practice in river restoration. Vegetation characteristics and diversity play a decisive role in maintaining ecological function in riparian zones. This study focuses on multi-scale distribution of herbaceous vegetation composition and diversity in riparian zones of three small–medium rivers in northern Zhejiang Province, China, through two years’ field investigations. Meanwhile, the main environmental and hydrological factors were analyzed by principal component analysis (PCA). The results indicated the following: (1) A total of 220 herbaceous plant species belonging to 55 families and 162 genera were recorded, with Poaceae (39 species, 17.73%) and Asteraceae (32 species, 14.55%) being the most abundant families. (2) Significant differences in riparian vegetation biomass and diversity were observed at both the river basin and river segment scales, in which upstream areas always showed higher richness and greater diversity of riparian vegetation. (3) The primary environmental factors influencing vegetation distribution varied with spatial scale: At the river scale, soil organic matter and water nitrogen were key factors affecting vegetation diversity, while riparian vegetation diversity was also influenced by water area. At the river segment scale, aquatic environmental factors exerted a more pronounced effect on vegetation diversity, with total phosphorus and nitrate nitrogen in water being the primary influencing factors. This research provides a theoretical basis for the restoration and sustainable management of riparian ecosystems in the study area and other similar regions. Full article

Amidst the rapid development of renewable energy, wind power, as a major renewable energy source, has raised ecological concerns regarding its impacts on ecosystems and biodiversity. Insects, as direct displays and feedback of the environment, have become a hot topic in ecology and conservation biology research due to the impact of environmental changes on them. So this study investigates the effects of wind power density on insect diversity and their mechanisms in the Ningxia desert steppe wind farms. The results indicated that minimal disturbance marginally increased insect aggregation at low wind power densities (2 turbines/km²). However, higher wind power densities caused pronounced insect population declines toward turbines (6, 11 turbines/km²), and with the increase in wind power density, the number of insects decreased significantly. Increased wind power disturbance led to decreases in soil total nitrogen (TN), total carbon (TC), nitrate nitrogen (NO₃⁻-N), and soil moisture content (SM) and a significant decrease in total phosphorus (TP). While direct impacts on vegetation were relatively minor and irregular, vegetation height exhibited strong positive correlations with soil nutrient depletion, suggesting that wind-induced soil degradation indirectly constrains plant growth. Consequently, the effect of wind power on insects is mediated through coupled vegetation–soil interactions. These findings underscore the necessity of integrating ecological thresholds into wind farm management protocols. Full article

Nitrogen is an essential macronutrient for crop growth. Although sorghum can tolerate poor soils, its low-nitrogen (LN) tolerance mechanisms remain underexplored. We conducted a genome-wide association study (GWAS) and RNA sequencing (RNA-seq) to dissect LN tolerance mechanisms in a diverse panel of 232 sorghum accessions. Phenotypic analyses revealed extensive variation in nitrogen-use efficiency traits, with shoot dry weight and shoot nitrogen accumulation in (SNAcc) showing the highest diversity. GWAS identified 10 quantitative trait loci harboring pleiotropic single-nucleotide polymorphisms (SNPs), including q1 (Chr3: 8.59–8.68 Mb), which is associated with biomass and nitrogen accumulation. Transcriptome profiling under LN stress revealed 6208 differentially expressed genes, with nitrate transporters showing genotype-specific regulation. Integration prioritized SORBI_3004G286700, where Hap2 accessions (14.66%) showed superior agronomic performance under LN conditions. We also identified pivotal transcription factors (TFs) that govern LN tolerance in sorghum, notably bHLH35 (SORBI_3007G051800) and three WRKY TFs, demonstrating constitutive upregulation in tolerant genotypes, whereas three previously uncharacterized TFs (MYB, bZIP, and B3) exhibited > 5-fold genotype-specific induction under LN. The integration of GWAS and transcriptome analyses offers an effective strategy for exploring candidate genes and elucidating nitrogen adaptation mechanisms in sorghum, while providing actionable molecular targets for precise breeding of nitrogen-efficient cultivars. Full article

Nitrogen is essential for durum wheat (Triticum turgidum subsp. durum) production, yet conventional sources such as urea-ammonium nitrate (UAN) and monoammonium phosphate (MAP) are energy-intensive to manufacture and, when mismanaged, contribute to soil degradation, nutrient runoff, and greenhouse gas emissions. Organic alternatives such as dairy manure solids (DMS) may reduce reliance on synthetic fertilizers but risk phosphorus accumulation and nutrient imbalances. Recirculating aquaculture systems generate nutrient-rich biosolids (RAB) that remain underutilized as fertilizers despite the rapid expansion of global aquaculture. We conducted a field experiment in Tucson, Arizona, USA, during the 2023–2024 winter growing season to evaluate RAB as a nitrogen source for Desert Durum^® wheat under irrigated arid conditions. Treatments supplied equivalent nitrogen rates using UAN, MAP, DMS, or RAB. Grain yields (3.6–4.8 t ha⁻¹) were not significantly affected by fertilizer source, but grain protein concentration was: RAB (101 ± 4 g kg⁻¹) was statistically comparable to UAN and MAP (96 ± 5 g kg⁻¹) and significantly higher than DMS (83 ± 4 g kg⁻¹) by ~20%. While this study was limited to small plots and a single season, these results demonstrate that aquaculture biosolids can maintain yields while enhancing protein compared with DMS, supporting their use as a supplement to or replacement for synthetic nitrogen fertilizers in arid wheat systems. Full article

Nitrogen use efficiency (NUE) in rice cultivation is a key determinant of sustainable agriculture, yet the interaction between NUE and the dynamics of rhizosphere soil microbial communities remain poorly understood. In this study, the changes in rhizosphere soil microbial community composition and function due to NUE were analyzed in six rice genotypes across six treatments. Through 16S rRNA/ITS amplicon sequencing, it was found that rice with different NUEs reshaped the rhizosphere soil microbial community structure, but did not significantly alter the α-diversity of the bacterial community. There was a notable difference in the average abundance of the fungus Arnium in the rhizosphere soil of high-NUE rice compared to low-NUE rice, with a 222.2% increase in the former. Correlation analysis indicated that in high-NUE rice, soil nitrate and nitrite contents drove changes in the fungal community, while in low-NUE rice, soil water-soluble nitrogen and total potassium contents were the key influencing factors for changes in the fungal and nitrogen-fixing bacterial communities, respectively. The findings of this study demonstrate a link between NUE-induced changes in the rhizosphere soil microbiome and nitrogen cycling in rice, providing a basis for targeted nitrogen fertilizer management approaches guided by microbial control. Full article

Oryza sativa L. is the largest food crop in the world. The harmful filamentous green algae Spirogyra in paddy fields poses a serious threat to O. sativa yield. Therefore, biological control for Spirogyra is important for sustainable agricultural development. The native fish species Acrossocheilus yunnanensis can graze on Spirogyra and exhibits strong environmental adaptability, providing a novel approach to the biological control of Spirogyra. Therefore, we designed the O. sativa+Spirogyra+A. yunnanensis co-culture system to study the effects of A. yunnanensis on O. sativa growth and physiological characteristics. The results indicated that Spirogyra stress significantly inhibited O. sativa biomass accumulation, root length and plant height development, reduced photosynthetic efficiency, and increased the contents of oxidative stress markers including malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). Interestingly, grazing of A. yunnanensis on Spirogyra increased the biomass of Oryza sativa by 58.60%, the root–shoot ratio by 78.01%, and the root length and plant height by 49.83% and 25.85%, respectively. Meanwhile, the soil nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and available phosphorus (AP) were enhanced, which improved O. sativa nutrient uptake and promoted photosynthetic pigment accumulation. This was manifested by an increase in chlorophyll content, net photosynthetic (Pn), transpiration rate, stomatal conductance (Gs), and intercellular CO₂ concentration (Ci). Grazing of A. yunnanensis on Spirogyra alleviated the oxidative damage to O. sativa induced by Spirogyra, as evidenced by decreased malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) level in both leaves and roots, along with increased protein content. This provides a new strategy for constructing a rice–fish symbiotic system by using indigenous fish species, achieving Spirogyra control and sustainable agricultural development. Full article

Soil acidification reduces the abundance and activity of beneficial microorganisms, impairs tea plant growth, and ultimately leads to a decline in tea quality. Maintaining healthy soil is critical for sustainable tea agriculture. However, the interactive effect of biochar and nitrogen fertilizer on the microbial community structure and function in acidic tea plantation soils remains unclear. This study was designed to explore whether the co-application of biochar and fertilizer could enhance soil properties and maintain microbial health in tea plantations. Three treatments were set up through a controlled pot experiment: no fertilizer or biochar application (B₀N₀), fertilizer without biochar (B₀N₁), and biochar with fertilizer (B₁N₁). High-throughput sequencing technology was used to investigate the characteristics of soil microbial communities in tea plantations. Biochar amendment increased soil pH by 0.8 units, organic matter and total nitrogen by 13.5% and 21.4%, and reduced NH₄⁺-N and NO₃⁻-N leaching by 10.8% and 12.9%, respectively. It also modulated microbial community structure, enhanced the abundance of nitrogen-cycling genes (e.g., narB, nirK, nosZ), and influenced nitrogen availability through adsorption. Nitrate was identified as the main factor shaping microbial communities under fertilization. These results highlight the potential of biochar as a sustainable amendment to improve soil health and nitrogen retention in tea cultivation systems. Further field studies are warranted to validate its efficacy in enhancing tea productivity and reducing environmental nitrogen losses under real-world conditions. Full article

The sharp increase in atmospheric nitrogen deposition has had profound effects on nitrogen availability and the photosynthetic capacity of terrestrial plants. Consequently, understanding the intricate trade-off between nitrogen sources and their allocation within leaves is essential for unraveling the photosynthetic responses of grassland ecosystems to nitrogen deposition. In a series of field experiments, the effects of different nitrogen forms (ammonium and nitrate nitrogen) on nitrogen assimilation and allocation in the C₄ plant Hemarthria altissima were thoroughly investigated. Towards the end of the growing season, H. altissima was observed to exhibit high photosynthetic efficiency. Ammonium nitrogen treatment notably enhanced photosynthetic nitrogen use efficiency (PNUE) by modifying the nitrogen allocation within the leaf’s photosynthetic apparatus and leaf area, leading to a significant improvement in photosynthetic efficiency and biomass accumulation. Under ammonium nitrogen treatment, H. altissima directed more nitrogen toward its carboxylation process and other protein-related functions to increase carboxylation efficiency, thereby facilitating the accumulation of photosynthetic products. In contrast, under nitrate nitrogen treatment, the plant balanced growth and light absorption by allocating nitrogen to leaf light-capturing proteins. The application of both ammonium and nitrate nitrogen resulted in increased nitrogen content in the soil, as ammonium nitrogen is converted to nitrate nitrogen through nitrification. The net photosynthetic rate (A_n), nitrogen allocation to photosynthetic components (N_psn), and chlorophyll content per unit area (Chl_area) were all significantly and positively correlated with photosynthetic nitrogen use efficiency (PNUE). Notably, under the sole NH₄⁺ treatment, nitrogen allocation to the photosynthetic components increased, which enhanced the NPQ and ETR in H. altissima leaves. These findings suggest that H. altissima preferentially utilizes ammonium nitrogen from the soil, optimizing its PNUE and biomass accumulation through a strategic allocation of nitrogen within its leaves. Further investigation is needed to explore how these nitrogen allocation strategies may vary under different environmental conditions and how they influence ecosystem-level productivity. Full article

Circular agriculture reclaims nutrients from waste streams to reduce fertilizer imports, mitigate environmental impacts, and close material loops. This review evaluates the agronomic performance of nitrogen, phosphorus, and potassium products recovered from wastewater, crop residues, and manure compared with conventional fertilizers. A structured literature survey identified 85 pot and field trials published between 2010 and 2024, covering ammonium salts, struvite, ashes, compost, digestate, biochar, hydrochar, and biostimulants. Ammonium sulfate and nitrate consistently matched synthetic yields (95–105%) due to their solubility and immediate N availability, while aqueous ammonia showed variable results depending on application timing and soil pH. Struvite and phosphorus-rich ashes performed best (90–100%) in neutral to slightly acidic soils, whereas organo-mineral phosphate fertilizers (85–95%) were less effective in alkaline soils. Potassium-rich ashes and waste mica were effective (80–95%) in soils with moderate cation exchange, though mica underperformed (60–75%) in coarse soils. Biochars and hydrochars improved soil water retention and nutrient exchange, yielding 90–110% of synthetic performance, while biostimulants increased yields by 8–20%. Recovered products demonstrate agronomic equivalence while offering co-benefits for soil health, waste management, and circular economy goals. Future work should prioritize long-term field validation, techno-economic analysis, and regulatory integration to enable large-scale adoption. Full article

Corn stover biochar amendment significantly influences nitrogen (N) and phosphorus (P) transformations, microbial community composition, and enzyme activities in continuous cropping soils. This study aimed to identify the optimal biochar application rate for enhancing N and P nutrient availability in Solanum lycopersicum L. continuous cropping systems, providing theoretical and technical foundations for mitigating continuous cropping obstacles. A soil experiment under rain-out shelters employed four treatments: 1% biochar (BA1), 3% biochar (BA3), 5% biochar (BA5), and a non-amended control (BA0). The results indicated that biochar amendment significantly elevated available phosphorus content in the soil while effectively suppressing its vertical migration; nitrate N content increased under BA1 treatment but decreased in the BA3 and BA5 groups; and the strength of the inhibition effect of biochar treatment on the vertical migration of nitrate N was BA1 > BA5 > BA0 > BA3. The addition of biochar treatment had no significant effect on the content of ammonium N but could inhibit the vertical migration of ammonium N. The addition of biochar treatment could increase the soil’s ammonium N content. The addition of biochar treatment increased soil catalase and urease and sucrase activities, decreased alkaline phosphatase activity, led to the promotion of nitrate reductase activity at low doses and its inhibition at high doses, and resulted in BA1 treatment having the largest soil enzyme index (SEI), which was the most favorable to increase the overall level of soil enzyme activities. Biochar significantly increased the relative abundance of Patescibacteria and Ciliophora while reducing Gemmatimonadota, Acidobacteriota, Nitrospirota, Ascomycota, and Chlorophyta. Comprehensive evaluation using gray relational analysis (GRA) demonstrated that the addition of 5% biochar resulted in the optimal overall performance, enhancing nitrogen and phosphorus transformation, improving microbial community structure, and harmonizing enzyme activities, thereby exhibiting considerable potential for alleviating the nutrient limitations of nitrogen and phosphorus in continuous cropping soils. Full article