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AbstractBoth nitrogen (N) deposition and biochar can affect the emissions of nitrous oxide (N2O), carbon dioxide (CO2) and ammonia (NH3) from different soils. Here, we have established a simulated wet N deposition experiment to investigate the effects of N deposition and biochar addition on N2O and CO2 emissions and NH3 volatilization from agricultural and forest soils. Repacked soil columns were subjected to six N deposition events over a 1-year period. N was applied at rates of 0 (N0), 60 (N60), and 120 (N120) kg Nh a?1 yr?1 without or with biochar (0 and 30 t ha?1 yr?1). For agricultural soil, adding N increased cumulative N2O emissions by 29.8% and 99.1% (p < 0.05) from the N60 and N120 treatments, respectively as compared to without N treatments, and N120 emitted 53.4% more (p < 0.05) N2O than the N60 treatment; NH3 volatilization increased by 33.6% and 91.9% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 43.6% more (p < 0.05) NH3 than N60; cumulative CO2 emissions were not influenced by N addition. For forest soil, adding N significantly increased cumulative N2O emissions by 141.2% (p < 0.05) and 323.0% (p < 0.05) from N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 75.4% more (p < 0.05) N2O than N60; NH3 volatilization increased by 39.0% (p < 0.05) and 56.1% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and there was no obvious difference between N120 and N60 treatments; cumulative CO2 emissions were not influenced by N addition. Biochar amendment significantly (p < 0.05) decreased cumulative N2O emissions by 20.2% and 25.5% from agricultural and forest soils, respectively, and increased CO2 emissions slightly by 7.2% and NH3 volatilization obviously by 21.0% in the agricultural soil, while significantly decreasing CO2 emissions by 31.5% and NH3 volatilization by 22.5% in the forest soil. These results suggest that N deposition would strengthen N2O and NH3 emissions and have no effect on CO2 emissions in both soils, and treatments receiving the higher N rate at N120 emitted obviously more N2O and NH3 than the lower rate at N60. Under the simulated N deposition circumstances, biochar incorporation suppressed N2O emissions in both soils, and produced contrasting effects on CO2 and NH3 emissions, being enhanced in the agricultural soil while suppressed in the forest soil. 相似文献
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Nitrous oxide (N2O) from agricultural soil is a significant source of greenhouse gas emissions. Biochar amendment can contribute to climate change mitigation by suppressing emissions of N2O from soil, although the mechanisms underlying this effect are poorly understood. We investigated the effect of biochar on soil N2O emissions and N cycling processes by quantifying soil N immobilisation, denitrification, nitrification and mineralisation rates using 15N pool dilution techniques and the FLUAZ numerical calculation model. We then examined whether biochar amendment affected N2O emissions and the availability and transformations of N in soils.Our results show that biochar suppressed cumulative soil N2O production by 91% in near-saturated, fertilised soils. Cumulative denitrification was reduced by 37%, which accounted for 85–95 % of soil N2O emissions. We also found that physical/chemical and biological ammonium (NH4+) immobilisation increased with biochar amendment but that nitrate (NO3−) immobilisation decreased. We concluded that this immobilisation was insignificant compared to total soil inorganic N content. In contrast, soil N mineralisation significantly increased by 269% and nitrification by 34% in biochar-amended soil.These findings demonstrate that biochar amendment did not limit inorganic N availability to nitrifiers and denitrifiers, therefore limitations in soil NH4+ and NO3− supply cannot explain the suppression of N2O emissions. These results support the concept that biochar application to soil could significantly mitigate agricultural N2O emissions through altering N transformations, and underpin efforts to develop climate-friendly agricultural management techniques. 相似文献
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A laboratory investigation was performed to compare the fluxes of dinitrogen (N2), N2O and carbon dioxide (CO2) from no-till (NT) and conventional till (CT) soils under the same water, mineral nitrogen and temperature status. Intact soil cores (0-10 cm) were incubated for 2 weeks at 25 °C at either 75% or 60% water-filled pore space (WFPS) with 15N-labeled fertilizers (100 mg N kg−1 soil). Gas and soil samples were collected at 1-4 day intervals during the incubation period. The N2O and CO2 fluxes were measured by a gas chromatography (GC) system while total N2 and N2O losses and their 15N mole fractions in the soil mineral N pool were determined by a mass spectrometer. The daily accumulative fluxes of N2 and N2O were significantly affected by tillage, N source and soil moisture. We observed higher (P<0.05) fluxes of N2+N2O, N2O and CO2 from the NT soils than from the CT soils. Compared with the addition of nitrate (NO3−), the addition of ammonium (NH4+) enhanced the emissions of these N and C gases in the CT and NT soils, but the effect of NH4+ on the N2 and/or N2O fluxes was evident only at 60% WFPS, indicating that nitrification and subsequent denitrification contributed largely to the gaseous N losses and N2O emission under the lower moisture condition. Total and fertilizer-induced emissions of N2 and/or N2O were higher (P<0.05) at 75% WFPS than with 60% WFPS, while CO2 fluxes were not influenced by the two moisture levels. These laboratory results indicate that there is greater potential for N2O loss from NT soils than CT soils. Avoiding wet soil conditions (>60% WFPS) and applying a NO3− form of N fertilizer would reduce potential N2O emissions from arable soils. 相似文献
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Benjamin Trost Annette Prochnow Michael Baumecker Andreas Meyer-Aurich Katrin Drastig Frank Ellmer 《Archives of Agronomy and Soil Science》2013,59(5):569-580
The aim of this study was to investigate the effect of supplemental irrigation on the amount of N2O emissions on a sandy soil in north-east Germany. N2O flux measurements were carried out over two vegetation periods from the emergence of plants to harvest. The level of N2O emissions was low, which is typical for sandy soils in north-east Germany. In both periods, irrigation had no increasing effect on N2O emissions. Relevant factors were the soil temperature and the soil water-filled pore space (WFPS), which were mainly influenced by weather conditions. This may indicate that nitrification was the main source of N2O emissions. In conclusion, this study has confirmed that sandy soils under weather conditions of north-east Germany generally have a very low potential for N2O emissions. 相似文献
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Taiki Mori Seiichi Ohta Shigehiro Ishizuka Ryota Konda Agus Wicaksono Joko Heriyanto 《Biology and Fertility of Soils》2014,50(1):45-51
We examined the effects of phosphorus (P) fertilization on N2O emissions from an Acacia mangium plantation in Indonesia. We focused on the roles of microbial and plant root activities using a trenching method to prepare root-excluded and root-including plots. In root-excluded plots, P application did not change the amount of N2O emissions. By contrast, in root-including plots, P application significantly reduced N2O emissions (from 71.1?±?20.2 to 19.3?±?5.1 mg N m?2 106 days?1). Lower total P, Bray-2 P, and Bio-P (microbial P determined by chloroform fumigation extraction method) contents in the soils of root-including plots as compared to root-excluded plots a few days after P application shows that acacia trees absorbed P fertilizer rapidly. This rapid P uptake probably relieved the P limitation of acacia and might have consistently increased root N uptake. This interpretation is supported by lower inorganic N content in P-applied soils (the average of three sampling times is 8.9 and 11.3 μg N g soil?1 in P-applied soils and soils without P application, respectively), which in turn decreased N2O emissions. Our study suggests that P fertilizer suppresses N2O emissions from tropical leguminous forest plantations. 相似文献
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Effect of mineral nitrogen fertilizer forms on N2O emissions from arable soils in winter wheat production
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Nitrogen fertilizers are supposed to be a major source of nitrous oxide (N2O) emissions from arable soils. The objective of this study was to compare the effect of N forms on N2O emissions from arable fields cropped with winter wheat (Triticum aestivum L.). In three field trials in North‐West Germany (two trials in 2011/2012, one trial in 2012/2013), direct N2O emissions during a one‐year measurement period, starting after application of either urea, ammonium sulfate (AS) or calcium ammonium nitrate (CAN), were compared at an application rate of 220 kg N ha?1. During the growth season (March to August) of winter wheat, N2O emission rates were significantly higher in all three field experiments and in all treatments receiving N fertilizer than from the non‐fertilized treatments (control). At two of the three sites, cumulative N2O emissions from N fertilizer decreased in the order of urea > AS > CAN, with emissions ranging from 522–617 g N ha?1 (0.24–0.28% of applied fertilizer) for urea, 368–554 g N ha?1 (0.17–0.25%) for AS, and 242–264 g N ha?1 (0.11–0.12%) for CAN during March to August. These results suggest that mineral nitrogen forms can differ in N2O emissions during the growth period of winter wheat. Strong variations in the seasonal dynamics of N2O emissions between sites were observed which could partly be related to weather events (e.g., precipitation). Between harvest and the following spring (post‐harvest period) no significant differences in N2O emissions between fertilized and non‐fertilized treatments were detected on two of three fields. Only on one site post‐harvest emissions from the AS treatment were significantly higher than all other fertilizer forms as well as compared to the control treatment. The cumulative one‐year emissions varied depending on fertilizer form across the three field sites from 0.05% to 0.51% with one exception at one field site (AS: 0.94%). The calculated overall fertilizer induced emission averaged for the three fields was 0.38% which was only about 1/3 of the IPCC default value of 1.0%. 相似文献
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Journal of Soils and Sediments - The reduction of nitrate (NO3ˉ) to nitrous oxide (N2O) and eventually to dinitrogen (N2) during denitrification in soil has rarely been studied at temperatures... 相似文献
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Yi Cheng Jing Wang Shen-Qiang Wang Jin-Bo Zhang Zu-Cong Cai 《Biology and Fertility of Soils》2014,50(7):1099-1108
Soil moisture changes, arising from seasonal variation or from global climate changes, could influence soil nitrogen (N) transformation rates and N availability in unfertilized subtropical forests. A 15?N dilution study was carried out to investigate the effects of soil moisture change (30–90 % water-holding capacity (WHC)) on potential gross N transformation rates and N2O and NO emissions in two contrasting (broad-leaved vs. coniferous) subtropical forest soils. Gross N mineralization rates were more sensitive to soil moisture change than gross NH4 + immobilization rates for both forest soils. Gross nitrification rates gradually increased with increasing soil moisture in both forest soils. Thus, enhanced N availability at higher soil moisture values was attributed to increasing gross N mineralization and nitrification rates over the immobilization rate. The natural N enrichment in humid subtropical forest soils may partially be due to fast N mineralization and nitrification under relatively higher soil moisture. In broad-leaved forest soil, the high N2O and NO emissions occurred at 30 % WHC, while the reverse was true in coniferous forest soil. Therefore, we propose that there are different mechanisms regulating N2O and NO emissions between broad-leaved and coniferous forest soils. In coniferous forest soil, nitrification may be the primary process responsible for N2O and NO emissions, while in broad-leaved forest soil, N2O and NO emissions may originate from the denitrification process. 相似文献
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Gross nitrogen transformations and related N2O emissions in uncultivated and cultivated black soil 总被引:1,自引:0,他引:1
A better understanding of the nitrogen (N) cycle in agricultural soils is crucial for developing sustainable and environmentally friendly N fertilizer management and to propose effective nitrous oxide (N2O) mitigation strategies. This laboratory study quantified gross nitrogen transformation rates in uncultivated and cultivated black soils in Northeast China. It also elucidated the contribution made by nitrification and denitrification to the emissions of N2O. In the laboratory, soil samples adjusted to 60 % water holding capacity (WHC) were spiked with 15NH4NO3 and NH4 15NO3 and incubated at 25 °C for 7 days. The size and 15N enrichment of the mineral N pools and the N2O emission rates were determined between 0 and 7 days. The results showed that the average N2O emission rate was 21.6 ng N2O-N kg?1 h?1 in cultivated soil, significantly higher than in the uncultivated soil (11.6 ng N2O-N kg?1 h?1). Denitrification was found to be responsible for 32.1 % of the N2O emission in uncultivated soil, and the ratio increased significantly to 43.2 % in cultivated soil, due to the decrease in soil pH. Most of the increase in net N2O-N emissions observed in the cultivated soil was resulting from the increased production of N2O through denitrification. Gross nitrification rate was significantly higher in the cultivated soil than in the uncultivated soil, and the ratio of gross nitrification rate/ammonium immobilization rate was 6.87 in cultivated soil, much larger than the uncultivated soil, indicating that nitrification was the dominant NH4 + consuming process in cultivated soil, and this will lead to the increased production of nitrate, whereas the increased contribution of denitrification to N2O emission promoted the larger emission of N2O. This double impact explains why the risk of N loss to the environment is increased by long-term cultivation and fertilization of native prairie sites, and controlling nitrification maybe effective to abate the negative environmental effects. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(7-8):633-640
Abstract Twenty soil samples were collected from three different locations in Nigeria to study the relationship between available water, organic matter content and particle size class with the objective to develop a prediction equation for available water capacity using these soil properties. A high correlation between available water and the textural separates of the soil was obtained, the highest correlation being with silt (r = 0.96). Organic matter in these soils did not highly correlate with available water (r = 0.22). Silt was found to contribute most to the total variation in available water (95.5%). However, when clay was introduced in the regression equation, 98% of the variation in available water capacity was accounted for with a smaller standard error (1.31) than when using silt content alone (1.97). The equation: Awc = 0.93 + 0.54 silt + 0.13 clay can be used to predict the available water capacity of these soils. 相似文献
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农田土壤N2O排放的连续自动测定方法 总被引:6,自引:2,他引:6
本文介绍了农田N2O排放连续自动测定系统的方法原理、系统整体构造和气路配置,并通过对华北平原旱地土壤夏玉米季N2O排放的连续观测,比较了连续自动测定方法与传统手动间歇取样测定方法的差异。结果表明,夏玉米季N2O排放具有明显的日排放规律,且在三叶期和十叶期施肥后存在明显的释放高峰;通过选取7:20、8:30、9:40、10:50、12:00、13:20、14:30、15:40、16:50和18:00不同采样时间的测定结果,分别模拟了间隔为3d和6d的排放总量,结果表明,间隔取样的累积排放结果与连续观测结果的差异,与采样当天中具体的采样时间紧密相关,间隔估算结果随着采样时间的延后具有先升高后降低的趋势,与N2O的日排放规律相一致。本研究中,不同时间间隔对估算结果影响不明显。 相似文献
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不同氮水平下黄瓜-番茄日光温室栽培土壤N_2O排放特征 总被引:4,自引:3,他引:4
为探讨日光温室黄瓜—番茄种植体系内N2O排放动态变化及其对不同氮水平的响应规律,采用密闭静态箱法,研究了常规氮量(黄瓜季1 200 kg/hm2,番茄季900 kg/hm2)、比常规氮量减25%(黄瓜季900 kg/hm2,番茄季675 kg/hm2)、减50%(黄瓜季600 kg/hm2,番茄季450 kg/hm2)以及不施氮对日光温室土壤N2O排放的影响。结果表明,温度是影响日光温室土壤N2O排放强度的重要因素,4-10月(平均气温为27.4℃)的N2O排放通量最高达818.4μg/(m2·h);而2-3月(平均气温15.1℃)以及11-12月(平均气温14.7℃)期间的N2O排放通量最高仅为464.5μg/(m2·h),比4-10月的N2O排放峰值降低了43.2%。N2O排放峰值在氮肥追施后5 d内出现,N2O排放量集中在氮肥施用后7 d内,可占整个监测期(271 d)排放量的64.7%~67.8%。施氮因增加了土壤硝态氮含量而引起N2O排放爆发式增长,0~10 cm土壤硝态氮含量与N2O排放量呈指数函数关系(P0.01)。日光温室黄瓜—番茄种植体系内的N2O排放量为0.99~9.92 kg/hm2,其中75.6%~90.0%由施氮造成。与常规氮用量相比,氮减量25%和50%处理的N2O排放量分别降低了40.4%和59.3%,总产量却增加4.9%和7.4%。综上所述,合理减少氮用量不仅可显著降低日光温室土壤N2O排放,而且不会引起产量的降低。该研究为日光温室蔬菜生产构建科学合理的施氮技术及估算中国设施农田温室气体排放量提供参考。 相似文献
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Yoshitaka Uchida Tim J. Clough Francis M. Kelliher Robert R. Sherlock 《Soil biology & biochemistry》2008,40(4):924-931
The dominant N2O emission source in New Zealand, calculated using the Intergovernmental Panel on Climate Change methodology, is agricultural soils. The largest source of N2O emissions in New Zealand occurs as a result of excreta deposition onto pasture during grazing. There is a dearth of studies examining the effect of soil compaction and soil aggregate size on N2O emissions from urine patches in grazed pastures. In this study, we repacked soil cores with four different soil aggregate sizes (<1.0–5.6 mm diameter), applied bovine urine, and then subjected the soil cores to four levels of soil compaction. Fluxes of N2O were monitored for 37 days after which soil cores were allowed to dry out prior to a rewetting event. There was an interaction between aggregate size and soil compaction with the cumulative loss of N2O over the first 37 days ranging from 0.3% to 9.6% of the urine-N applied. The highest N2O emissions occurred from the smallest and most compacted aggregates. Even under the highest levels of compaction the N2O loss from the large aggregates (4.0–5.6 mm diameter) was <1% of the urine-N applied. Reasons for the observed differences in the N2O flux from the different-sized aggregates included varying gas diffusivities and higher rates of denitrification in the smallest aggregates, as evidenced by the disappearance of nitrate. 相似文献
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Winnie Ntinyari Rüdiger Reichel Joseph P. Gweyi-Onyango Mekonnen Giweta Holger Wissel Cargele Masso Roland Bol Nicolas Brüggemann 《Soil Use and Management》2023,39(3):1125-1139
The application of nitrogen (N) fertilizers and liming (CaCO3) to improve soil quality and crop productivity are regarded as effective and important agricultural practices. However, they may increase greenhouse gas (GHG) emissions. There is limited information on the GHG emissions of tropical soils, specifically when liming is combined with N fertilization. We therefore conducted a full factorial laboratory incubation experiment to investigate how N fertilizer (0 kg N ha−1, 12.5 kg N ha−1 and 50 kg N ha−1) and liming (target pH = 6.5) affect GHG emissions and soil N availability. We focussed on three common acidic soils (two ferralsols and one vertisol) from Lake Victoria (Kenya). After 8 weeks, the most significant increase in cumulative carbon dioxide (CO2) and nitrous oxide (N2O) fluxes compared with the unfertilized control was found for the two ferralsols in the N + lime treatment, with five to six times higher CO2 fluxes than the control. The δ13C signature of soil-emitted CO2 revealed that for the ferralsols, liming (i.e. the addition of CaCO3) was the dominant source of CO2, followed by urea (N fertilization), whereas no significant effect of liming or of N fertilization on CO2 flux was found for the vertisol. In addition, the N2O fluxes were most significantly increased by the high N + lime treatment in the two ferralsols, with four times and 13 times greater N2O flux than that of the control. No treatment effects on N2O fluxes were observed for the vertisol. Liming in combination with N fertilization significantly increased the final nitrate content by 14.5%–39% compared with N fertilization alone in all treatment combinations and soils. We conclude that consideration should be given to the GHG budgets of agricultural ferralsols since liming is associated with high liming-induced CO2 and N2O emissions. Therefore, nature-based and sustainable sources should be explored as an alternative to liming in order to manage the pH and the associated fertility of acidic tropical soils. 相似文献
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Erik S. Button Karina A. Marsden Philip D. Nightingale Elizabeth R. Dixon David R. Chadwick David L. Jones Laura M. Cárdenas 《European Journal of Soil Science》2023,74(2):e13363
Agricultural soils are a major source of the potent greenhouse gas and ozone depleting substance, N2O. To implement management practices that minimize microbial N2O production and maximize its consumption (i.e., complete denitrification), we must understand the interplay between simultaneously occurring biological and physical processes, especially how this changes with soil depth. Meaningfully disentangling of these processes is challenging and typical N2O flux measurement techniques provide little insight into subsurface mechanisms. In addition, denitrification studies are often conducted on sieved soil in altered O2 environments which relate poorly to in situ field conditions. Here, we developed a novel incubation system with headspaces both above and below the soil cores and field-relevant O2 concentrations to better represent in situ conditions. We incubated intact sandy clay loam textured agricultural topsoil (0–10 cm) and subsoil (50–60 cm) cores for 3–4 days at 50% and 70% water-filled pore space, respectively. 15N-N2O pool dilution and an SF6 tracer were injected below the cores to determine the relative diffusivity and the net N2O emission and gross N2O emission and consumption fluxes. The relationship between calculated fluxes from the below and above soil core headspaces confirmed that the system performed well. Relative diffusivity did not vary with depth, likely due to the preservation of preferential flow pathways in the intact cores. Gross N2O emission and uptake also did not differ with depth but were higher in the drier cores, contrary to expectation. We speculate this was due to aerobic denitrification being the primary N2O consuming process and simultaneously occurring denitrification and nitrification both producing N2O in the drier cores. We provide further evidence of substantial N2O consumption in drier soil but without net negative N2O emissions. The results from this study are important for the future application of the 15N-N2O pool dilution method and N budgeting and modelling, as required for improving management to minimize N2O losses. 相似文献
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Ute Szukics Evelyn Hackl Sophie Zechmeister-Boltenstern Angela Sessitsch 《Biology and Fertility of Soils》2009,45(8):855-863
Denitrification represents one of the main microbial processes producing the primary and secondary greenhouse gases nitrous oxide (N2O) and nitric oxide (NO) in soils. It is well established that abiotic factors like the soil water content and the availability of nitrogen (N) are key parameters determining the activity of denitrifiers in soils. However, soils differing regarding their characteristics such as the content of Corg, the soil texture or the pH value may respond in specific manners to equivalent changes in soil moisture and N input. Thus, short-term incubation experiments were performed to test and compare the capacity of two contrasting Austrian forest soils to respond to mineral N application at increased soil water contents. Soils from the pristine Rothwald forest (rich in Corg) and the more acidic Schottenwald forest (poor in Corg) were amended with either NH 4 + -N or NO 3 ? -N and were incubated at 40% and 70% water-filled pore space for 4 days. Changes in mineral N pools, nitrite reductase activity and NO and N2O emission rates were measured, and the abundance and structural community composition of the functional group involved in nitrite reduction were analysed via quantitative real-time polymerase chain reaction and terminal restriction fragment length polymorphism analysis of the nirK gene. Rapid and distinct activity responses to increased soil moisture and altered mineral nitrogen availability were observed in two contrasting forest soils. In both soils, nitrogen oxide emission rates were stimulated by N inputs and, depending on the soil moisture status, either NO or N2O emission was prevailing. However, different N cycling processes appeared to predominate in either soil under equivalent treatment. Nitrogen oxide emissions peaked following NO 3 ? application in Schottenwald soils but were the highest after NH 4 + application in Rothwald soils. Denitrifying (nirK) communities differed significantly in Rothwald and Schottenwald soils; however, changes in the community structure were marginal during the short-term incubation. Abundances of nirK genes remained unaffected by N application in either soil. The soil water content affected nirK gene abundances only in Rothwald soil, indicating a distinct reaction of nitrite reducing communities in the two soils. 相似文献