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15N tracing was carried out on sandy loam soil amended with (i) mineral nitrogen-phosphorus-potassium fertilizer (NPK) alone, (ii) half mineral N and half N from chicken manure (HFC), or (iii) half mineral N and half N from cattle manure (HCM), for 8 years. Cumulative N2O emissions during incubation were 30.2 µg N kg− 1 in the NPK treatment, which increased to 37.8 and 51.3 µg N kg− 1 in the HFC and HCM treatments, respectively. The majority of N2O emissions in all the treatments were attributed to nitrification (81.0% in the NPK treatment, 83.0% in the HFC treatment, and 85.1% in the HCM treatment). Compared with NPK, HCM treatment caused a significant increase in the gross rate of nitrification, while HFC treatment slightly enhanced the rate of dissimilatory NO3− reduction to NH4+. Additionally, HFC treatment achieved higher gross rates of organic N mineralization, and both HFC and HCM treatments had higher NH4+ mineralization-immobilization turnover (MIAT) rates than NPK treatment. The results suggest that application of cattle or chicken manure increased soil NH4+ availability. The gross rate of NO3− adsorption in the HCM treatment was greater than that in the NPK treatment, while the release of adsorbed NO3− in the HFC treatment was slower than that in the NPK treatment, indicating that application of cattle or chicken manure lowered the potential for NO3− leaching in soil. Overall, combining cattle or chicken manure with mineral fertilizer decreased NO3− availability but increased NH4+ availability, leading to higher N2O emissions through nitrification. Our results suggest that organic manures should be applied with nitrification inhibitors in sandy loam soil containing low organic carbon to increase soil fertility and mitigate N2O emissions. [ABSTRACT FROM AUTHOR]

The article describes the case of a seven-year-old boy with lumbago and progressive leg numbness and diagnosed with torque teno mini virus (TTMV):: RARA. Topics discussed including finding on magnetic resonance imaging (MRI), the patient's development of Klebsiella pneumonia infection and parainfluenza virus infection during treatment of combined chemotherapies, and conclusion on the cause of TTMV:RARA.

Approximately 17% of the land worldwide is considered highly vulnerable to non‐native plant invasion, which can dramatically alter nutrient cycles and influence greenhouse gas (GHG) emissions in terrestrial and wetland ecosystems. However, a systematic investigation of the impact of non‐native plant invasion on GHG dynamics at a global scale has not yet been conducted, making it impossible to predict the exact biological feedback of non‐native plant invasion to global climate change. Here, we compiled 273 paired observational cases from 94 peer‐reviewed articles to evaluate the effects of plant invasion on GHG emissions and to identify the associated key drivers. Non‐native plant invasion significantly increased methane (CH4) emissions from 129 kg CH4 ha−1 year−1 in natural wetlands to 217 kg CH4 ha−1 year−1 in invaded wetlands. Plant invasion showed a significant tendency to increase CH4 uptakes from 2.95 to 3.64 kg CH4 ha−1 year−1 in terrestrial ecosystems. Invasive plant species also significantly increased nitrous oxide (N2O) emissions in grasslands from an average of 0.76 kg N2O ha−1 year−1 in native sites to 1.35 kg N2O ha−1 year−1 but did not affect N2O emissions in forests or wetlands. Soil organic carbon, mean annual air temperature (MAT), and nitrogenous deposition (N_DEP) were the key factors responsible for the changes in wetland CH4 emissions due to plant invasion. The responses of terrestrial CH4 uptake rates to plant invasion were mainly driven by MAT, soil NH4+, and soil moisture. Soil NO3−, mean annual precipitation, and N_DEP affected terrestrial N2O emissions in response to plant invasion. Our meta‐analysis not only sheds light on the stimulatory effects of plant invasion on GHG emissions from wetland and terrestrial ecosystems but also improves our current understanding of the mechanisms underlying the responses of GHG emissions to plant invasion. [ABSTRACT FROM AUTHOR]

Purpose: The impact of dairy farm effluent and manure applications upon gas emissions from soil is of concern for agronomic, ecological, and environmental reasons. Yet it remains unclear how the optimized manure and effluent additions may affect gas (nitrous oxide (N2O), nitric oxide (NO), and ammonia (NH3)) emissions during wheat cultivation. Materials and methods: We conducted a field experiment in Zhuzhen (Jiangsu), China, from November 2018 to May 2019 to examine the effects of effluent and manure on gas emissions from the wheat fields that had seven treatments (4 replicates, 28 plots): no fertilizer (control); inorganic fertilizer at a conventional application rate of 200 kg N ha−1 (NPK); 100 kg N ha−1 inorganic fertilizer plus 100 (DE1), 150 (DE2), and 250 (DE3) kg N ha−1 farm dairy effluent; 100 kg N ha−1 inorganic fertilizer plus 100 kg N ha−1 farm dairy manure (SM1); and 150 kg N ha−1 inorganic fertilizer plus 50 kg N ha−1 farm dairy manure (SM2). Results and discussion: Applying dairy effluent during the wheat season significantly (P < 0.05) increased NH3 emissions from 1.83 (NPK) to 3.81 kg N ha−1 (DE1) and 11.4 kg N ha−1 (DE3), probably due to elevated levels of soil NH4+ and pH, with no discernable impact on N2O emissions compared with NPK. The greater application of effluent in the DE3 treatment increased NO emissions significantly by 33.3% relative to NPK. The combined application of manure and urea significantly reduced N2O and NO emissions by 25.2–27.6% and 8.3–45.8%, respectively, but increased NH3 emissions in the SM1 treatment by 73.8%, when compared with NPK. Conclusions: Overall, our results suggest that replacing 25% of the current conventional chemical N application rate with dairy manure could considerably mitigate gas emissions in the wheat season. [ABSTRACT FROM AUTHOR]

A 15N tracing incubation study was carried out using a sandy loam soil without (control) and with field-aged biochar (biochar) to investigate the mechanisms underlying the effects of field-aged biochar on nitrous oxide (N2O) emissions. During the incubation, carried out at 40%, 60%, and 80% water-filled pore space (WFPS), cumulative N2O emission decreased from 24.13–26.40 μg N kg−1 in the control soil to 18.27–23.94 μg N kg−1 in the biochar soil, with a reduction of 9.3–24.3%. The contribution of autotrophic nitrification to total N2O production was 81.8–87.6% in the control soil under 40–80% WFPS, which was significantly reduced by field-aged biochar to 67.1–78.6%. Under 60% WFPS, the gross rates of autotrophic nitrification and gross mineralization were reduced from 11.95 and 4.43 μg N g−1 d−1, respectively, in the control soil to 7.32 and 0.60 μg N g−1 d−1, respectively, in the biochar soil. The field-aged biochar increased the NH4+ immobilization rate by 440%, primarily by immobilizing NH4+ into the recalcitrant organic N pool. Both the turnover rate of NH4+ mineralization-immobilization and the ratio of nitrification to NH4+ immobilization were reduced under biochar amendment, consequently lowering the supply of NH4+ for nitrifiers. In addition, compared with the control soil, the gross rate of NH4+ adsorption was significantly higher in the biochar soil. Taken together, our results suggest that field-aged biochar contributes to mitigating N2O emissions, primarily by decreasing the autotrophic nitrification rate through a reduced NH4+ supply due to increased mineral N immobilization and adsorption and lowered organic N mineralization. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in a subtropical tea (Camellia sinensis (L.) O. Kuntze) plantation in Jiangsu Province, China, including the following treatments: no nitrogen (N) fertilizer (control), conventional mineral N fertilizer (urea) (CN), soybean cake fertilizer (SF), pig manure (PM), cattle manure (CaM), chicken manure (CM), and CM + biochar (CMB). Cumulative nitrous oxide (N2O) and nitric oxide (NO) emissions were 4.8 ± 0.1 and 3.7 ± 0.3 kg N ha−1 year−1 under CN, respectively, and increased to 5.4 ± 0.2 and 4.6 ± 0.3 kg N ha−1 year−1 under SF (P < 0.05), respectively. Treatments with livestock manures (PM, CaM, and CM) reduced N2O (41.4–49.6%) and NO (46.5–59.8%) emission in comparison to CN. Combined amendment of CM and biochar more effectively reduced N2O emissions than CM treatment alone. Based on a meta-analysis of 26 global paired measurements in acid soils, the threshold of C/N ratios of organic fertilizers between the positive and negative responses of N2O emissions to organic fertilizers was 8.6 with a range of 4.5–22.3 (95% confidence interval), indicating that reduced N2O emission under PM, CaM and CM was potentially due to their C/N ratios compared to the threshold. Organic fertilizer application did not influence tea yield, while combined application of CM and biochar increased tea yield and resulted in the least yield-scaled N2O emission. N2O and NO emission factors for N fertilizers applied under CN were 1.9 ± 0.1% and 1.5 ± 0.2%, respectively, and reduced to 0.08 ± 0.04% and 0.12 ± 0.04% under CMB, respectively. The results suggest that tea plantations in the subtropical region are hotspots for N2O and NO emissions. Combined application of chicken manure and biochar could mitigate N gas emissions and increase yield in the tea plantation systems. [ABSTRACT FROM AUTHOR]

Plant invasion can strongly influence carbon (C) cycling processes, thus it may affect climate change by altering C sequestration and greenhouse gas emissions in the invaded ecosystem. Since 1979, the exotic Spartina alterniflora has rapidly expanded in China's coastal areas, where significant increase in methane (CH4) emissions has been documented from post‐invaded sites. However, a mechanistic understanding of the structural and functional changes of associated methanogens accompanying this invasion remains elusive.Here we conducted integrated biogeochemical investigations on methanogenic substrates, activity, and diversity to identify implications of S. alterniflora invasion for methanogenesis in coastal wetlands. To do this, we collected and analysed 0–50 cm soil profiles from an uncolonised tidal flat (TF) and salt marshes that S. alterniflora has invaded for 1 year (SA‐1) and 12 years (SA‐12) in Jiangsu, China. Methanogenic community composition was characterised by massive parallel sequencing. The rates and pathways of methanogenesis were determined by adding trace concentrations of 13C‐labelled substrates to anaerobic incubated samples.Our results revealed that 12‐year invasion of S.alterniflora drastically increased CH4 production potential by one order of magnitude over that of TF. This substantial increase was primarily attributed to methanogenesis from trimethylamine; its rates increased by two orders of magnitude over TF whereas those from acetate and H2/CO2 increased far less. Hydrogenotrophic methanogenesis was the dominant pathway operating in the TF, but methanotrophic pathway contributed most to CH4 production in the surface layer of SA‐1 and uppermost 40‐cm layers of SA‐12. Consistent with these observations, the dominant methanogens shifted from obligate hydrogenotrophic Methanococcales in TF to potential methylamine‐utilising Methanosarcinaceaein SA‐12. Our Mantel analysis indicated that 'non‐competitive' trimethylamine, derived from cytoplasmic osmolytes of S. alterniflora, was the major driver of this change in methanogenic community composition.Synthesis. Our results suggest that invasive Spartina alternifloraplants gradually facilitated the local dominance of methylotrophic Methanosarcinaceae by changing the key type of methanogenic substrate in coastal marshes. Shifts in methanogen communities and enhanced availability of trimethylamine elevated the rates and importance of methylotrophic methanogenesis, thereby markedly increasing CH4 production potential and emission rates in this type of ecosystem. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to evaluate the combined or individual effects of biochar and nitrapyrin (a nitrification inhibitor) on N2O and NO emissions from a sandy loam soil cropped to maize. The study included nine treatments: addition of urea alone or combined with nitrapyrin to soils that had been amended with biochar at 0, 3, 6, and 12 t ha−1 in the preceding year, and a control without the addition of N fertilizer. Peaks in N2O and NO flux occurred simultaneously following fertilizer application and intense rainfall events, and the peak of NO flux was much higher than that of N2O following application of basal fertilizer. Mean emission ratios of NO/N2O ranged from 1.11 to 1.72, suggesting that N2O was primarily derived from nitrification. Cumulative N2O and NO emissions were 1.00 kg N2O-N ha−1 and 1.39 kg NO-N ha−1 in the N treatment, respectively, decreasing to 0.81-0.85 kg N2O-N ha−1 and 1.31-1.35 kg NO-N ha−1 in the biochar amended soils, respectively, while there was no significant difference among the treatments. NO emissions were significantly lower in the nitrapyrin treatments than in the N fertilization-alone treatments (P < 0.05), but there was no effect on N2O emissions. Neither biochar nor nitrapyrin amendment affected maize yield or N uptake. Overall, our results showed that biochar amendment in the preceding year had little effect on N2O and NO emissions in the following year, while the nitrapyrin decreased NO, but not N2O emissions, probably due to suppression of denitrification caused by the low soil moisture content. [ABSTRACT FROM AUTHOR]

There is ample evidence that methane (CH) emissions from natural wetlands exhibit large spatial variations at a field scale. However, little is known about the metabolically active methanogens mediating these differences. We explored the spatial patterns in active methanogens of summer inundated Calamagrostis angustifolia marsh with low CH emissions and permanently inundated Carex lasiocarpa marsh with high CH emissions in Sanjiang Plain, China. In C. angustifolia marsh, the addition of C-acetate significantly increased the CH production rate, and Methanosarcinaceae methanogens were found to participate in the consumption of acetate. In C. lasiocarpa marsh, there was no apparent increase in the CH production rate and no methanogen species were labeled with C. When CO-H was added, however, CH production was found to be due to Fen Cluster ( Methanomicrobiales) in C. angustifolia marsh and Methanobacterium Cluster B ( Methanobacteriaceae) together with Fen Cluster in C. lasiocarpa marsh. These results suggested that CH was produced primarily by hydrogenotrophic methanogens using substrates mainly derived from plant litter in C. lasiocarpa marsh and by both hydrogenotrophic and acetoclastic methanogens using substrates mainly derived from root exudate in C. angustifolia marsh. The significantly lower CH emissions measured in situ in C. angustifolia marsh was primarily due to a deficiency of substrates compared to C. lasiocarpa marsh. Therefore, we speculate that the substrate source regulates both the type of active methanogens and the CH production pathway and consequently contributes to the spatial variations in CH productions observed in these freshwater marshes. [ABSTRACT FROM AUTHOR]

Coastal salt marshes are sensitive to global climate change and may play an important role in mitigating global warming. To evaluate the impacts of Spartina alterniflora invasion on global warming potential ( GWP) in Chinese coastal areas, we measured CH4 and N2O fluxes and soil organic carbon sequestration rates along a transect of coastal wetlands in Jiangsu province, China, including open water; bare tidal flat; and invasive S. alterniflora, native Suaeda salsa, and Phragmites australis marshes. Annual CH4 emissions were estimated as 2.81, 4.16, 4.88, 10.79, and 16.98 kg CH4 ha−1 for open water, bare tidal flat, and P. australis, S. salsa, and S. alterniflora marshes, respectively, indicating that S. alterniflora invasion increased CH4 emissions by 57-505%. In contrast, negative N2O fluxes were found to be significantly and negatively correlated ( P < 0.001) with net ecosystem CO2 exchange during the growing season in S. alterniflora and P. australis marshes. Annual N2O emissions were 0.24, 0.38, and 0.56 kg N2O ha−1 in open water, bare tidal flat and S. salsa marsh, respectively, compared with -0.51 kg N2O ha−1 for S. alterniflora marsh and −0.25 kg N2O ha−1 for P. australis marsh. The carbon sequestration rate of S. alterniflora marsh amounted to 3.16 Mg C ha−1 yr−1 in the top 100 cm soil profile, a value that was 2.63- to 8.78-fold higher than in native plant marshes. The estimated GWP was 1.78, −0.60, −4.09, and −1.14 Mg CO2eq ha−1 yr−1 in open water, bare tidal flat, P. australis marsh and S. salsa marsh, respectively, but dropped to −11.30 Mg CO2eq ha−1 yr−1 in S. alterniflora marsh. Our results indicate that although S. alterniflora invasion stimulates CH4 emissions, it can efficiently mitigate increases in atmospheric CO2 and N2O along the coast of China. [ABSTRACT FROM AUTHOR]

There are large temporal and spatial variations of methane (CH) emissions from natural wetlands. To understand temporal changes of CH production potential (MPP), soil samples were collected from a permanently inundated Carex lasiocarpa marsh and a summer inundated Calamagrostis angustifolia marsh over the period from June to October of 2011. MPP, dissolved organic carbon (DOC) concentration, abundance and community structure of methanogenic archaea were assessed. In the C. lasiocarpa marsh, DOC concentration, MPP and the methanogen population showed similar seasonal variations and maximal values in September. MPP and DOC in the C. angustifolia marsh exhibited seasonal variations and values peaked during August, while the methanogen population decreased with plant growth. Methanogen abundance correlated significantly ( P = 0.02) with DOC only for the C. lasiocarpa marsh. During the sampling period, the dominant methanogens were the Methanosaetaceae and Zoige cluster I (ZC-Ι) in the C. angustifolia marsh, and Methanomicrobiales and ZC-Ι in the C. lasiocarpa marsh. MPP correlated significantly ( P = 0.04) with DOC and methanogen population in the C. lasiocarpa marsh but only with DOC in the C. angustifolia marsh. Addition of C. lasiocarpa litter enhanced MPP more effectively than addition of C. angustifolia litter, indicating that temporal variation of substrates is controlled by litter deposition in the C. lasiocarpa marsh while living plant matter is more important in the C. angustifolia marsh. This study indicated that there was no apparent shift in the dominant types of methanogen during the growth season in the species-specific freshwater wetlands. Temporal variation of MPP is controlled by substrates and substrate-driven changes in the abundance of methanogenic archaea in the C. lasiocarpa marsh, while MPP depends only on substrate availability derived from root exudates or soil organic matter in the C. angustifolia marsh. [ABSTRACT FROM AUTHOR]

To evaluate the long–term effect of compost (CM) and inorganic fertilizer (NPK) application on microbial community structure and organic carbon (OC) accumulation at aggregate scale, soils from plots amended with CM, NPK and no fertilizer (control) for 20 years (1989–2009) were collected. Soil was separated into large macroaggregate (>2,000 μm), small macroaggregate (250–2,000 μm), microaggregate (53–250 μm), silt (2–53 μm) and clay fraction (<2 μm) by wet-sieving, and their OC concentration and phospholipid fatty acids (PLFA) were measured. The 20-year application of compost significantly (P<0.05) increased OC by 123–134% and accelerated the formation of macroaggregates, but decreased soil oxygen diffusion coefficient. NPK mainly increased OC in macroaggregates and displayed weaker influence on aggregation. Bacteria distributed in all aggregates, while fungi and actinobacteria were mainly in macroaggregates and microaggregates. The ratio of monounsaturated to branched (M/B) PLFAs, as an indicator for the ratio of aerobic to anaerobic microorganisms, increased inversely with aggregate size. Both NPK and especially CM significantly (P<0.05) decreased M/B ratios in all aggregates except the silt fraction compared with the control. The increased organic C in aggregates significantly (P<0.05) negatively correlated with M/B ratios under CM and NPK. Our study suggested that more efficient OC accumulations in aggregates under CM–treated than under NPK–treated soil was not only due to a more effective decrease of actinobacteria, but also a decrease of monounsaturated PLFAs and an increase of branched PLFAs. Aggregations under CM appear to alter micro-habitats to those more suitable for anaerobes, which in turn boosts OC accumulation. [ABSTRACT FROM AUTHOR]

Invasion by the exotic species Spartina alterniflora, which has high net primary productivity and superior reproductive capacity compared with native plants, has led to rapid organic carbon accumulation and increased methane (CH) emission in the coastal salt marsh of China. To elucidate the mechanisms underlying this effect, the methanogen community structure and CH production potential as well as soil organic carbon (SOC), dissolved organic carbon, dissolved organic acids, methylated amines, aboveground biomass, and litter mass were measured during the invasion chronosequence (0-16 years). The CH production potential in the S. alterniflora marsh (range, 2.94-3.95 μg kg day) was significantly higher than that in the bare tidal mudflat. CH production potential correlated significantly with SOC, acetate, and trimethylamine concentrations in the 0-20 cm soil layer. The abundance of methanogenic archaea also correlated significantly with SOC, and the dominant species clearly varied with S. alterniflora-driven SOC accumulation. The acetotrophic Methanosaetaceae family members comprised a substantial proportion of the methanogenic archaea in the bare tidal mudflat while Methanosarcinaceae family members utilized methylated amines as substrates in the S. alterniflora marsh. Ordination analysis indicated that trimethylamine concentration was the primary factor inducing the shift in the methanogenic archaea composition, and regressive analysis indicated that the facultative family Methanosarcinaceae increased linearly with trimethylamine concentration in the increasingly sulfate-rich salt marsh. Our results indicate that increased CH production during the S. alterniflora invasion chronosequence was due to increased levels of the non-competitive substrate trimethylamine and a shift in the methanogenic archaea community. [ABSTRACT FROM AUTHOR]

Increased nitrogen (N) input to ecosystems could alter soil organic carbon (C) dynamics, but the effect still remains uncertain. To better understand the effect of N addition on soil organic C in wetland ecosystems, a field experiment was conducted in a seasonally inundated freshwater marsh, the Sanjiang Plain, Northeast China. In this study, litter production, soil total organic C (TOC) concentration, microbial biomass C (MBC), organic C mineralization, metabolic quotient ( qCO) and mineralization quotient ( qmC) in 0-15 cm depth were investigated after four consecutive years of N addition at four rates (CK, 0 g N m year; low, 6 g N m year; moderate, 12 g N m year; high, 24 g N m year). Four-year N addition increased litter production, and decreased soil organic C mineralization. In addition, soil TOC concentration and MBC generally increased at low and moderate N addition levels, but declined at high N addition level, whereas soil qCO and qmC showed a reverse trend. These results suggest that short-term N addition alters soil organic C dynamics in seasonally inundated freshwater marshes of Northeast China, and the effects vary with N fertilization rates. [ABSTRACT FROM AUTHOR]

Significant spatial variation in CH emissions is a well-established feature of natural wetland ecosystems. To understand the key factors affecting CH production, the variation in community structure of methanogenic archaea, in relation to substrate and external environmental influences, was investigated in selected wetlands across China, using denaturing gradient gel electrophoresis. Case study areas were the subtropical Poyang wetland, the warm-temperate Hongze wetland, the cold-temperate Sanjiang marshes, and the alpine Ruoergai peatland on the Qinghai-Tibetan Plateau. The topsoil layer in the Hongze wetland exhibited the highest population of methanogens; the lowest was found in the Poyang wetland. Maximum CH production occurred in the topsoil layer of the Sanjiang Carex lasiocarpa marsh, the minimum was observed in the Ruoergai peatland. CH production potential was significantly correlated with the dissolved organic carbon (DOC) concentration but not with the abundance or diversity indices of methanogenic archaea. Phylogenetic analysis and DOC concentration indicated a shift in the dominant methanogen from the hydrogenotrophic Methanobacteriales in DOC-rich wetlands to Methanosarcinaceae with a low affinity in wetlands with relatively high DOC and then to the acetotrophic methanogen Methanosaetaceae with a high affinity in wetlands with low DOC, or with high DOC but rich sulfate-reducing bacteria. Therefore, it is proposed that the dominant methanogen type in wetlands is primarily influenced by available DOC concentration. In turn, the variation in CH production potential in the wetlands of eastern China is attributable to differences in the DOC content and the dominant type of methanogen present. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to evaluate the influence of the continuous application of organic and mineral N fertilizer on N2O and NO emissions under maize and wheat rotation on the North China Plain. This study included eight treatments: no fertilizer (control); mineral N fertilizer (Nmin) at a rate of 200 kg N ha−1 per season; 50% mineral fertilizer N plus 50% cattle manure N (50% CM), 50% chicken manure N (50% FC) or 50% pig manure N (50% FP); 75% mineral fertilizer N plus 25% cattle manure N (25% CM), 25% chicken manure N (25% FC) or 25% pig manure N (25% FP). The annual N2O and NO emissions were 2.71 and 0.39 kg N ha−1, respectively, under the Nmin treatment, with an emission factor of 0.50% for N2O and 0.07% for NO. Compared with the Nmin treatment, N2O emissions did not differ when 50% of the mineral N was replaced with manure N (50% CM, 50% FC and 50% FP), while annual NO emissions were significantly reduced by 49.0% and 27.8% under 50% FC and 50% FP, respectively. In contrast, annual N2O emissions decreased by 21–38% compared to the Nmin treatment when 25% of the mineral N was replaced with manure N (25% CM, 25% FC and 25% FP). Most of the reduction occurred during the maize season. The 25% CM, 25% FC and 25% FP treatments had no effect on NO emissions compared to the Nmin treatment. There was no obvious difference in annual N2O and NO emissions among the organic manures at the same application rate, probably due to their similar C/N ratio. Replacing a portion of the mineral fertilizer N with organic fertilizer N did not significantly affect crop grain yield, except for the 50% FC treatment in the wheat season. Overall, the results suggest that the combined application of 25% organic manure N plus 75% mineral fertilizer N had the most potential to mitigate N2O emissions while not affecting crop yield in the maize and wheat rotation system in this area of China. [ABSTRACT FROM AUTHOR]