ABSTRACT Excessive application of nitrogen (N) fertilizer has acidified soils to pH levels below the optimum, posing a threat to tea plant cultivation. Organic livestock manure rich in alkaline substances can counteract the H+ produced by soil nitrification of N fertilizer. However, how ameliorating acidification using livestock manure affects nitrification and greenhouse gas nitrous oxide (N2O) emissions in tea-planted soils remains unclear. Here, by adding four types of manure (cow, sheep, chicken, and pig) at rates of 0, 100, and 200 mg N kg−1 into a tea-planted soil, we showed that all manure additions alleviated soil acidification and increased net N mineralization and nitrification significantly, with the increases becoming more pronounced with increasing rate. While soil cumulative N2O emissions were enhanced significantly by sheep, chicken, and pig manure and reduced significantly by cow manure at the high rate, with opposite trends at the low rate. Net nitrification and cumulative N2O emissions were significantly and negatively correlated with carbon (C)/N of added manure at both rates and at the high rate alone, respectively. Our findings highlight the importance of selecting the appropriate livestock manure (i.e. high C/N) to alleviate soil acidification while minimizing nitrification and N2O emissions.

Forest fine root litter enters agricultural soils in some cases and its decomposition would change the soil’s properties. However, how this process further influences the ammonia (NH3) volatilization and nitrous oxide (N2O) emission from agricultural soil receiving fertilizer nitrogen (N) is unknown. Here, we conducted a soil pot experiment to investigate the responses of the aforementioned gaseous N losses during wheat season to fine root litters derived from Populus deltoides (RP) and Metasequoia glyptostroboides (RM) incorporations. The results showed that two forest fine root litters reduced total NH3 losses by 30.6−31.9% from 180 kg N ha−1 applied to farmland soil, and this effect was attributed to decreased soil urease activity and ammonium-N during the basal N fertilization period. Whether receiving fertilizer N or not, N2O emissions from farmland soil were significantly (p < 0.05) mitigated by 62.8–68.2% and 43.0−50.0% following the RP and RM incorporation, respectively. Lower N2O emission was ascribed to increased soil pH but decreased soil nitrate-N and bulk density. In addition, less AOA and AOB amoA but more nosZ gene abundances explained the fine root litter-induced N2O mitigation effect. Neither forest fine root litter exerted a negative effect on wheat grain yield and crop N use efficiency in N-added agriculture soil. In conclusion, forest fine root litter incorporation could help to mitigate gaseous N losses via NH3 volatilization and N2O emission from fertilizer-N-applied agricultural soils, and without crop production loss.

The identification of forage species with Biological Nitrification Inhibition (BNI) capacity is a promising strategy to inhibit soil nitrification and reduce nitrogen (N) losses. This study evaluated the BNI capacity of five Urochloa genotypes (Camello, Cayman, Marandú, Mulato II, Talismán) and their impact on biomass yield and nitrogen uptake (NU). The BNI capacity, biomass yield, N content, and NU of five Urochloa genotypes were compared. Significant differences in BNI capacity were observed between genotypes (p &lt; 0.009). Cayman and Marandú presented the highest BNI values (87.41 and 87.21%, respectively), higher than those of Mulato II, Talismán and Camello (78.20, 81.77 and 82.63%, respectively). Regarding biomass yield, Cayman and Marandú stood out with 3093.5 and 2911.7 kg DM ha−1, respectively. Talismán and Camello showed higher N concentrations in the biomass (1.64 and 1.63%). In terms of NU, Cayman recorded the highest efficiency (47.32 kg N ha−1), surpassing Marandú, Camello, Talisman and Mulato II (42.83, 42.77, 41.53 and 37.23 kg N ha−1, respectively; p &lt; 0.0001). BNI capacity influences biomass yield and nitrogen uptake. The Cayman genotype is positioned as a promising forage alternative for the development of more efficient and sustainable livestock systems by promoting more efficient N use.

Manure distribution interacts with soil moisture and nitrate availability in controlling soil N2O emissions

Traditional detection methods for soil nitrate nitrogen (NO3--N), a critical nutrient for crop growth, suffer from poor timeliness and susceptibility to matrix interference. To address these issues, this study presents a novel dual-band frequency-splitting coupled sensor with a concentric copper ring structure for in situ rapid detection of soil NO3--N via dielectric spectroscopy. The key technological innovation lies in using the low-frequency band (1-50 MHz) to isolate water and salinity interferences via stable impedance matching of the copper rings and capturing the characteristic NO3--N relaxation signals in the high-frequency band (100-500 MHz) via enhanced electromagnetic coupling. Field trials across five soil types (brown, black, red, saline-alkali, and loess) demonstrated excellent performance, with determination coefficient (R2) values of 0.943-0.987, mean absolute error values of ≤0.75 mg/kg, root-mean-square error values of ≤0.92 mg/kg, and millisecond-level response. Signal drift remained <0.25 mg/kg even under extreme conditions (-5 °C, 90% relative humidity (RH)), with Pearson correlation coefficient values of 0.995-0.999 in typical agricultural scenarios (pre/postfertilization and precipitation). The developed sensor eliminates the need for sampling and pretreatment, reducing the detection time from 3-5 days using traditional methods to milliseconds, and provides high-precision data for dynamic nitrogen management. Moreover, the IoT integration potential of the sensor advances smart agriculture and sustainable development.

Sorgoleone, a lipophilic benzoquinone allelochemical exuded by sorghum [Sorghum bicolor (L) Moench] root, represents a promising multitarget botanical herbicide with significant potential for sustainable weed management. Sorgoleone inhibits weed growth through concurrent disruption of mitochondrial respiration, photosystem II electron transfer, carotenoid biosynthesis, and root H+-ATPase activity. It exhibits broad-spectrum activity against terrestrial weeds and aquatic plants, with heightened efficacy against small-seeded species and dicots. Environmentally, sorgoleone is also a biological nitrification inhibitor (BNI) that could suppress soil nitrification (enhancing nitrogen use efficiency by 15-20%) and enhances arbuscular mycorrhizal symbiosis. Due to its important bioactivities and potential application value, plant extraction, chemical synthesis, and biosynthetic synthesis have been explored to overcome production constraints of sorgoleone. This review provides a summary and discussion of the biological activities, herbicidal mechanisms, total synthesis, and biosynthesis of sorgoleone, serving as a basis for further research and applications.

Sustainability: The sustainability of ecosystem services, greenhouse gas emissions, and soil fertility in temperate soils requires knowledge of their carbon (C) and nitrogen (N) fluxes. The biogeochemical model of decomposition, which is process-based and also known as Nitrification, denitrification, and plant-soil processes, incorporates both washout processes and interactions to represent these fluxes. This study is based on the DNDC model of carbon fluxes in temperate soils. It evaluates its performance in monitoring variations in soil organic carbon, CO2, N2O emissions, and nitrate leaching, compared with various land management approaches. The field data were used to verify the model simulations, and the findings revealed excellent agreement, indicating the model's potential as a decision-support tool for studies of agronomic practice sustainability and environmental impact. These findings highlight the availability of precise inputs based on the location, calibration to increase reliability in the simulation, application of regional mitigation strategies, and change of strategies to steer changes in the targeted land-use paths.

Nitrate induces increases in cadmium accumulation by reducing manganese competitive absorption of wheat plant.

IntroductionStraw returning is an important agricultural measure for improving soil health; however, the mechanism driving how it shapes the characteristics and multifunctionality of crop rhizosphere microbial communities in black-soil areas remains unclear.MethodsThrough a 3-year field experiment, combined with high-throughput sequencing, co-occurrence network analysis, and multi-model coupling, this study systematically analyzed the effects of different straw-returning rates (no straw returning, half-dose straw returning, and full-dose straw returning) on the characteristics and multifunctionality of crop rhizosphere soil microbial communities in typical black-soil areas.ResultsThe results showed that the half-dose straw-returning treatment significantly increased soil microbial diversity, whereas the full-dose straw-returning treatment significantly enriched bacterial groups such as o_Rokubacteriales and f_Anaerolineaceae and fungal groups such as Ophiocordyceps and Gigaspora. Soil nitrate nitrogen, organic carbon, microbial biomass nitrogen, microbial biomass phosphorus, and invertase activity were important factors affecting soil multifunctionality. Furthermore, co-occurrence network analysis indicated that the nodes, edges, and average degree of the fungal community under the half-dose straw-returning treatment significantly increased by 9.41, 15.93, and 30.13%, respectively, compared with those in the no-straw-returning treatment. There was a significant positive correlation between the complexity of the fungal network and microbial network and the soil multifunctional index. Additionally, microbial network complexity is a direct key factor that drives improvements in soil multifunctionality, and microbial diversity indirectly enhances soil multifunctionality by regulating microbial network complexity. Moreover, soil multifunctionality was significantly positively correlated with crop biomass and grain yield.DiscussionThis study elucidates the mechanism by which straw returning enhances black-soil fertility through the regulation of soil microbial networks, providing a theoretical basis and practical value for sustainable agricultural development and straw resource utilization in black-soil regions.

Agricultural soil microbiomes are essential for element cycling, fertility maintenance, and crop productivity, yet how key functional taxa interact with environmental factors to shape community assembly remains poorly understood. In this transcontinental study spanning diverse vegetation types, we demonstrate that ammonia-oxidizing archaea mediate soil microbial community assembly in response to pH and nitrate levels, with evidence of nonlinear threshold effects driven by nitrate. These findings underscore the pivotal role of keystone taxa in structuring soil biodiversity and ecological functions. Our study offers valuable insights into microbially mediated carbon and nitrogen cycling under climate change and supports crop-specific soil management strategies for sustainable agriculture.

Affordable optical data from Unmanned Aerial Vehicles (UAVs) coupled with process-based models could constitute an integrative platform to map complex spatio-temporal patterns of nitrate leaching and reduce uncertainties in tightening the nitrogen (N) cycle of silvopastoral systems. This study uses field data from a commercial farm in Denmark with lactating sows housed in paddocks with pastures flanking a central zone of poplars, either pruned (P) or unpruned (tall, T), each with resources (feed and hut) on the same (S) or opposite side (O) of the tree zone. The poplar leaf area index derived from canopy cover using a computer vision approach on true-colour UAV imagery was fed to a process-based model alongside soil data and geostatistical analyses to derive the soil water balance across the paddocks and explicitly map the variation in soil nitrate leaching. The results showed clear patterns not seen before of nitrate leaching hotspots shifting from high values in the pre-study year without animals to diluted lower values in the main study year involving the pigs. The results also showed a seasonal and spatial variation of 7 to 860 kg N ha−1 year−1, a wide leaching range otherwise difficult to capture, by employing only a process-based model using mean effective parameters. Nitrate leaching was in the order PO &gt; PS &gt; TO &gt; TS. The N cycle was tightened with T regardless of S/O. The approach could be improved with more machine learning-aided process-based modelling to operationally monitor complex silvopastoral systems to alleviate nitrate leaching in outdoor pig systems.

Abstract It is unclear how plant growth‐promoting rhizobacteria (PGPR) affect soil multifunctionality (SMF) and production function (SPF) along planting densities. To address this issue, Bacillus licheniformis (PGPR) was inoculated in maize fields with five planting densities (D1–D5 from low to high) in the drought‐prone region of the Yunnan Plateau, southwest China from 2022 to 2023. Data indicated that under non‐inoculation (CK), SMF tended to increase from D1 to D4 ( p &lt; 0.05) and then stabilize in D5 across two growing seasons. Yet, SPF was observed to elevate steadily with increasing densities. PGPR inoculation significantly improved SMF (0.129) and SPF (0.508) under increasing planting densities. Meanwhile, soil carbon and phosphorus cycling indices significantly improved by 0.272 and 0.069 ( p &lt; 0.05), respectively, whereas no significant change was observed in the nitrogen cycling index ( p &gt; 0.05), relative to CK. Increased carbon cycling index was significantly associated with improved soil soluble organic carbon (2.26%) concentration and enhanced carbon‐related extracellular enzyme activities (9.57%). Similarly, phosphorus‐related extracellular enzyme activity significantly increased by 10.51% ( p &lt; 0.05). Interestingly, no significant changes were observed in the levels of soil total nitrogen, ammonium nitrogen and nitrate nitrogen, and the activities of nitrogen‐related enzymes across planting densities. The above‐mentioned phenomenon can be mechanistically explained by the variations in rhizosphere microbiomes, and the accelerated carbon exchanges with nitrogen/phosphorus, which amplified SMF for higher SPF by reshaping the nutrient trade‐off in plant–soil‐microbe system through PGPR‐enhanced microbial activity. Read the free Plain Language Summary for this article on the Journal blog.

Aims Nitrogen (N) deposition has emerged as a major driver of ecological change in alpine grasslands of the Qinghai-Tibetan Plateau under global climate change. To predict the ecological consequences of increasing nitrogen deposition, nitrogen addition experiments have been widely employed as a key methodological approach to simulate this process. However, the effects of nitrogen addition—considering its rate, duration, and form—on carbon (C) dynamics in these ecosystems remain inconsistent across studies. Understanding these effects is critical for predicting global carbon stocks and guiding sustainable grassland management. Methods We conducted a meta-analysis of 57 peer-reviewed studies (794 observations) to quantify the response of alpine grassland C dynamics to N addition. Results N addition significantly increased plant-derived carbon inputs, increasing aboveground biomass by 42.7%, belowground biomass by 16.2%, and dissolved organic carbon (DOC) by 10.7%. The soil organic carbon (SOC) content increased by 3.6% overall. Conversely, soil respiration decreased by 5.1%, whereas the microbial respiration rate increased by 21.9%. The addition of nitrogen decreased the soil pH by 0.20 units and the soil C/N ratio by 1.7%. The soil ammonium (NH4+) and nitrate (NO3-) contents decreased by 20.1% and 52.1%, respectively. The microbial biomass nitrogen (MBN) increased by 14.5%, whereas the microbial biomass carbon (MBC) decreased by 2.8%. The soil fungal-to-bacterial ratio (F/B) decreased by 31.0%. Conclusion These results indicate that shifts in microbial community structure drive SOC dynamics in alpine grasslands. Short-term N addition (≤5 years; ≤30 kg N ha -1 yr -1 ) enhances SOC through increased plant biomass and microbial C sequestration. However, long-term additions promote C loss via soil acidification and a critical shift in the microbial community, notably a decreased fungal-to-bacterial ratio. To sustain alpine ecosystem function, N addition rates should not exceed 10 kg N ha -1 yr -1 . Future research should prioritize interactions between N deposition status and soil acidification/microbial function in high-altitude regions.

Additives in agricultural plastics can leach into the surrounding soil during use or improper disposal. Their subsequent degradation rates directly regulate whether they persist and accumulate to levels with ecotoxicological effects or are rendered benign. However, which soil properties primarily regulate the degradation of additives remains unclear (e.g. soil carbon, pH, available nutrients, microbial biomass and community structure). We assessed the degradation of the common plastic additives with different functionalities (DEHP (di(2-ethylhexyl) phthalate; plasticiser), 2-hydroxy-4-n-octyloxybenzophenone (benzophenone-12; BP12; UV stabiliser) and AO168 (tris(2,4-di-tert-butylphenyl) phosphite; antioxidant)) in soils under controlled moisture and temperature conditions over 21days across contrasting agricultural soils from six countries across a global transect (Australia, Brazil, Egypt, India, Vietnam and the UK). DEHP followed zero-order degradation kinetics, with negligible degradation in soils with low microbial biomass. BP12 degraded fastest via first-order degradation kinetics via ether cleavage and hydroxyl loss. The degradation of DEHP and BP12 was correlated with soil microbial biomass and nitrate concentration. BP12 degradation products detected included benzophenone and benzoic acid. DEHP is degraded via β-oxidation of alkyl groups to dibutyl phthalate and diethyl phthalate and through ester hydrolysis to phthalic acid. AO168 degraded via abiotic oxidation and phosphate ester hydrolysis to 2,4-di-tert-butyl-phenol, and degradation was not well correlated with any measured soil variable. Overall, these results show that the components of additive mixtures leached into soils will degrade at different rates due to varying mechanisms and controls exerted by the soil microbial biomass. Plastic additives have differing potentials to persist in agricultural soils globally, with some likely to accumulate to levels that may impact soil function and pose an ecotoxicological threat to soil biota.

Microbial-driven nitrogen retention in optimized shelter forests: A solution for agricultural non-point source pollution control.

Integrated metagenomic and metabolomic analyses reveal that nitrogen fertilizer reduction combined with biochar application improves the soil microenvironment of Phoebe bournei seedlings.

Sedimentological and geochemical records of early Pleistocene glacial-interglacial cycles driving cyclic precipitation trends in playa lacustrine strata of Death Valley, CA: A novel application of 17O in soil nitrate as a paleo-precipitation proxy in arid systems

Seasonal and spatial dynamics of soil nitrogen cycling microbial communities in an agricultural riparian ecosystem.

Divergent effects of straw and straw-derived biochar on soil N transformation and N2O emissions: a global meta-analysis.

Microbial mechanisms of biochar reducing methane emission in a rice-crayfish integrated system.