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1.
土壤添加沼渣对温室气体排放及小麦生长的影响   总被引：1，自引：1，他引：0  
Digestate, the product obtained after anaerobic digestion of organic waste for biogas production, is rich in plant nutrients and might be used to fertilize crops. Wheat(Triticum spp. L.) was fertilized with digestate, urea, or left unfertilized and cultivated in the greenhouse for 120 d. Emissions of greenhouse gasses(carbon dioxide(CO_2), methane(CH_4), and nitrous oxide(N_2O)) were monitored and plant growth characteristics were determined at harvest. The digestate was characterized for heavy metals, pathogens, and C and N mineralization potential in an aerobic incubation experiment. No Salmonella spp., Shigella spp., or viable eggs of helminths were detected in the digested pig slurry, but the number of faecal coliforms was as high as 3.6 × 10~4colony-forming units(CFU) g-~(1)dry digestate. The concentrations of heavy metals did not surpass the upper limits established by US Environmental Protection Agency(EPA). After 28 d, 17% of the organic C(436 g kg~(-1)dry digestate) and 8% of the organic N(6.92 g kg~(-1)dry digestate)were mineralized. Emissions of CO_2 and CH_4 were not significantly affected by fertilization in the wheat-cultivated soil, but digestate significantly increased the cumulative N_2O emission by 5 times compared to the urea-amended soil and 63 times compared to the uncultivated unfertilized soil. It could be concluded that digestate was nutrient rich and low in heavy metals and pathogens, and did not affect emissions of CH_4 and CO_2 when applied to a soil cultivated with wheat, but increased emission of N_2O.  相似文献   

2.
Bio-organic fertilizers enriched with plant growth-promoting microbes(PGPMs)have been widely used in crop fields to promote plant growth and maintain soil microbiome functions.However,their potential effects on N2O emissions are of increasing concern.In this study,an in situ measurement experiment was conducted to investigate the effect of organic fertilizer containing Trichoderma guizhouense(a plant growth-promoting fungus)on soil N2O emissions from a greenhouse vegetable field.The following four treatments were used:no fertilizer(control),chemical fertilizer(NPK),organic fertilizer derived from cattle manure(O),and organic fertilizer containing T.guizhouense(O+T,referring to bio-organic fertilizer).The abundances of soil N cycling-related functional genes(amoA)from ammonium-oxidizing bacteria(AOB)and archaea(AOA),as well as nirS,nirK,and nosZ,were simultaneously determined using quantitative PCR(qPCR).Compared to the NPK plot,seasonal total N2O emissions decreased by 11.7%and 18.7%in the O and O+T plots,respectively,which was attributed to lower NH4+-N content and AOB amoA abundance in the O and O+T plots.The nosZ abundance was significantly greater in the O+T plot,whilst the AOB amoA abundance was significantly lower in the O+T plot than in the O plot.Relative to the organic fertilizer,bio-organic fertilizer application tended to decrease N2O emissions by 7.9%and enhanced vegetable yield,resulting in a significant decrease in yield-scaled N2O emissions.Overall,the results of this study suggested that,compared to organic and chemical fertilizers,bio-organic fertilizers containing PGPMs could benefit crop yield and mitigate N2O emissions in vegetable fields.  相似文献   

3.
Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO_2) evolution from biochar-amended soils at very high temperatures, as observed for tropical surface soils, is limited but urgently needed for the development of region-specific biochar management targeted to optimize biochar effects on soil functions. Here, we investigated the temperature sensitivity of soil respiration to the addition of different rates of Miscanthus biochar(0, 6.25, 12.5, and 25 Mg ha~(-1)) in two types of soils with contrasting textures. Biochar-amended soil treatments and their controls were incubated at constant temperatures of 20, 30, and 40℃. Overall, our results show that: i) considering data from all treatments and temperatures, the addition of biochar decreased soil CO_2 emissions when compared to untreated soils;ii) CO_2 emissions from biochar-amended soils had a higher temperature sensitivity than those from biochar-free soils; iii) the temperature sensitivity of soil respiration in sandy soils was higher than that in clay soils; and iv) for clay soils, relative increases in soil CO_2 emissions from biochar-amended soils were higher when the temperature increased from 30 to 40℃, while for sandy soils, the highest temperature responses of soil respiration were observed when increasing the temperature from 20 to 30℃. Together, these findings suggest a significantly reduced potential to increase soil organic carbon stocks when Miscanthus biochar is applied to tropical soils at high surface temperatures, which could be counteracted by the soil-and weather-specific timing of biochar application.  相似文献   

4.
中国东北休闲期稻田温室气体排放   总被引：2，自引：0，他引：2  
CH4, N2O and CO2 emissions from northeast Chinese rice fields were measured in the fallow season （November to March） to investigate the effects of freezing-thawing on the emissions. Both CH4 emission from and atmospheric CH4 oxidation by the soil occurred, but the flux was small. During the fallow season, rice fields acted as a minor source of atmospheric CH4, which accounted for about 1% of the CH4 emission during the rice growing period. The field was also a substantial source of atmospheric N20, which ranged between 40 to 77 mg m-2 and eu=counted for 40%-50% of the annual N20 emission. The largest N20 flux was observed in the thawing period during the fallow season. Laboratory incubation tests showed that the largest N20 flux came from the release of N20 trapped in frozen soil. Tillage and rice straw application （either mulched on the soil surface or incorporated in the soil） stimulated the CH4 and CO2 emissions during the fallow season, but only straw application stimulated N2O emission substantially.  相似文献   

5.
Intensity of tillage practices can enhance organic matter decomposition, increasing CO2 emissions from soil to the atmosphere. Conservation tillage （CT） has been proposed as a means of counteracting potential damages to the environment. In this study the effects of two CT systems, reduced tillage in a long-term experiment （RTL） and no-tillage in a short-term experiment （NTs）, were compared to traditional tillage （TT） in the long （TTL） and short-term experiments （TTs）. CO2 fluxes, total soil organic carbon （SOC） and dehydrogenase activity （DHA） were evaluated at 0-5, 5-10 and 10-15 cm depths throughout the three years studied （Oct. 2006 Jul. 2009）. Traditional tillage increased C02 emissions compared to CT. The CT treatments （RTL and NTs） accumulated more SOC in the surface layer （0 5 cm） than the TT treatments （TTL and TTs）. SOC accumulation was moderate but DHA consistently increased in CT in the surface soil, especially with a legume crop included in the crop rotation. Values of stratification ratio of all parameters studied were higher in the CT treatments （RTL and NTs）. The agricultural and environmental benefits derived from CT make this system recommendable for semi-arid Mediterranean rain-fed agriculture.  相似文献   

6.
A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region,China.Of the fourteen randomly distributed treatments consisting of different combinations of organic manure,inorganic nitrogen (N),phosphorus (P),and potassium (K),and rice straw,eight were selected for the present study in 2007.Application of organic manure plus straw significantly increased soil organic carbon (SOC) content of the topsoil (0-10 cm) compared to that of chemical fertilizers alone.The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments.The stable carbon isotope ratio (δ 13 C) ranged from 24‰ to 28‰ and increased gradually with depth.The content of SOC was significantly (P < 0.05) negatively correlated with δ 13 C.In the 0-20 cm layer,the δ 13 C value significantly decreased in the treatments of manure alone (M),manure and chemical N and P fertilizers (MNP),manure and chemical N,P,and K fertilizers (MNPK),manure,rice straw,and chemical N fertilizer (MRN),and chemical N fertilizer and rice straw (CNR),as compared with the no-fertilizer control.In the 30-50 cm layer,however,the ratio significantly increased in all the treatments except Treatment CNR.Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks,being faster in the manure treatments than the chemical fertilizer treatments.The average rate of mineralization varied from 55.36 to 75.46 mL CO 2 kg-1 d-1 and that of stable mineralization from 10 to 20 mL CO 2 kg-1 d-1.In eight weeks of incubation,cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments,being the highest in Treatment MRN.Combined humus in the soil was mainly (over 50%) composed of tightly combined fraction.The loosely combined humus and its ratio of humic acid (HA) to fulvic acid (FA) significantly increased with long-term application of organic manure and chemical fertilizers.It could be concluded that the cycle of organic C in the paddy soil ecosystem studied was stable over the long-term application of fertilizers and continued cultivation.  相似文献   

7.
菜地土壤中氮肥的反硝化损失和N2O排放   总被引：4，自引：0，他引：4  
A field experiment was conducted on Chinese cabbage （Brassica campestris L. ssp. pekinensis （Lour.） Olsson） in a Nanjing suburb in 2003. The experiment included 4 treatments in a randomized complete block design with 3 replicates： zero chemical fertilizer N （CK）; urea at rates of 300 kg N ha^-1 （U300） and 600 kg N ha^-1 （U600）, both as basal and two topdressings; and polymer-coated urea at a rate of 180 kg N ha^-1 （PCU180） as a basal application. The acetylene inhibition technique was used to measure denitrification （N2 ＋ N2O） from intact soil cores and N2O emissions in the absence of acetylene. Results showed that compared to （3K total denitrification losses were significantly greater （P ≤ 0.05） in the PCU180, U300, and U600 treatments,while N2O emissions in the U300 and U600 treatments were significantly higher （P ≤ 0.05） than （3K. In the U300 and U600 treatments peaks of denitrification and N2O emission were usually observed after N application. In the polymer-coated urea treatment （PCU180） during the period 20 to 40 days after transplanting, higher denitrification rates and N2O fluxes occurred. Compared with urea, polymer-coated urea did not show any effect on reducing denitrification losses and N2O emissions in terms of percentage of applied N. As temperature gradually decreased from transplanting to harvest, denitrification rates and N2O emissions tended to decrease. A significant （P ≤0.01） positive correlation occurred between denitrification （r = 0.872） or N2O emission （r = 0.781） flux densities and soil temperature in the CK treatment with a stable nitrate content during the whole growing season.  相似文献   

8.
不同水稻、小麦品种对N2O排放的影响   总被引：3，自引：0，他引：3  
B. GOGOI  K. K. BARUAH 《土壤圈》2012,22(1):112-121
Plant species of cropping systems may affect nitrous oxide (N2O) emissions. A field experiment was conducted to investigate dynamics of N2O emissions from rice-wheat fields from December 2006 to June 2007 and the relationship between soil and plant parameters with N2O emissions. The results indicated that N2O emissions from different wheat varieties ranged from 12 to 291 μg N2O-N m-2 h-1 and seasonal N2O emissions ranged from 312 to 385 mg N2O-N m-2. In the rice season, it was from 11 to 154 μg N2O-N m-2 h-1 with seasonal N2O emission of 190--216 mg N2O-N m-2. The seasonal integrated flux of N2O differed significantly among wheat and rice varieties. The wheat variety HUW 234 and rice variety Joymoti showed higher seasonal N2O emissions. In the wheat season, N2O emissions correlated with soil organic carbon (SOC), soil NO3--N, soil temperature, shoot dry weight, and root dry weight. Among the variables assessed, soil temperature followed by SOC and soil NO3--N were considered as the important variables influencing N2O emission. N2O emission in the rice season was significantly correlated with SOC, soil NO3--N, soil temperature, leaf area, shoot dry weight, and root dry weight. The main driving forces influencing N2O emission in the rice season were soil NO3--N, leaf area, and SOC.  相似文献   

9.
氮施用水平和方式对高粱作物产量和质量的影响   总被引：1，自引：0，他引：1  
A. RASHID  R. U. KHAN  H. ULLAH 《土壤圈》2008,18(2):236-241
A field study was conducted for two years at the Arid Zone Research Institute, Dera Ismail Khan, Pakistan, to determine the optimum level of nitrogen and efficient application method in the production of sorghum （Sorghum bicolor L.）. Using four levels of nitrogen, i.e., 0, 60, 90, and 120 kg ha^-1, and two different application methods （soil application and foliar spray）, the experiment was laid out in a split-plot design, where the main plots were used to determine the effective method of application and the subplots were used to detect the influence of N levels on the grain yield. The average data obtained after two years of study indicated an increase in the grain yields with an increase in N levels irrespective of the method used of N application. The grain yield increased from 2.92 to 5.61 t ha^-1 in the plots that were treated with 90 kg N ha^-1 compared with the control plots. Quadratic regression analysis showed that the increase in the yield was higher at the lower levels of N compared with the succeeding higher levels. The soil application method, producing an average grain yield of 4.79 t ha^-1, was found to be superior to the foliar spray method with an average grain yield of 4.56 t ha^-1. The protein content of the grain showed a linear increase with N application, attaining the maximum at 120 kg N ha^-1 in both the methods of N application. In addition, compared with the method of soil application, higher crude protein contents were observed using the method of foliar spray at all N levels.  相似文献   

10.
Biochar is a carbon-rich product obtained by biomass pyrolysis and considered a mean of carbon sequestration. In this research, a sandy calcareous soil from the Farm of the College of Food & Agriculture Sciences, King Saud University, Saudi Arabia, was amended with either woody waste of Conocarpus erectus L.(CW) or the biochar(BC) produced from CW at rates of 0(control), 10, 30 and 50 g kg-1. The effects of the amendments on soil p H, dissolved organic carbon(DOC), microbial biomass carbon(MBC), CO2 emission and metabolic quotient(q CO2) of the sandy calcareous soil were studied in a 60-d incubation experiment. The results showed that the addition of CW led to a significant decrease in soil p H compared to the control and the addition of BC. The CO2-C emission rate was higher in the first few days of incubation than when the incubation time progressed. The cumulative CO2-C emission from the soil amended with CW, especially at higher rates, was higher(approximately 3- to 6-fold) than that from the control and the soil amended with BC. The BC-amended soil showed significant increases in CO2-C emission rate during the first days of incubation as compared to the non-amended soil, but the increase in cumulative CO2-C emission was not significant after 60 d of incubation. On the other hand, CW applications resulted in considerably higher cumulative CO2-C emission, MBC and DOC than the control and BC applications. With the exception of 0 day(after 1 h of incubation), both CW and BC applications led to lower values of q CO2 as compared to the control. The power function kinetic model satisfactorily described the cumulative CO2-C emission. Generally, the lowest values of CO2 emission were observed in the soil with BC, suggesting that the contribution of BC to CO2 emission was very small as compared to that of CW.  相似文献   

11.
Greenhouse gases are known to play an important role in global warming. In this study, we determined the effects of selected soil and climate variables on nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from a tropical grassland fertilized with chicken slurry, swine slurry, cattle slurry, and cattle compost. Cumulative N2O emissions did not differ between treatments and varied from 29.26 to 32.85 mg N m-2. Similarly, cumulative CH4 emissions were not significantly different among the treatments and ranged from 6.34 to 57.73 mg CH4 m-2. Slurry and compost application induced CO2 emissions that were significantly different from those in the control treatment. The CH4 conversion factors measured were 0.21%, 1.39%, 4.39%, and 5.07% for cattle compost, chicken slurry, swine slurry, and cattle slurry, respectively, differing from the recommendations of the Intergovernmental Panel on Climate Change (IPCC). The fraction of added N emitted as N2O was 0.39%, which was lower than the IPCC default value of 2%. Our findings suggest that N2O emissions could be mitigated by replacing synthetic fertilizer sources with either biofertilizer or compost. Our results indicate the following:N2O emission was mainly controlled by soil temperature, followed by soil moisture and then soil NH4+ content; CH4 fluxes were mainly controlled by soil moisture and chamber headspace temperature; and CO2 fluxes were mainly controlled by chamber headspace temperature and soil moisture.  相似文献   

12.
Nitrogen-use efficiency in arable agriculture after organic fertilization can be improved by the incorporation of digestate into soil and through the use of nitrification inhibitors. To test the efficiency and the interaction of these measures, a laboratory microcosm study was conducted with undisturbed samples from two arable soils – a Gleysol and a Plaggic Anthrosol. Treatments were digestate application by injection to 15 or 20 cm depths or by trailing hose with subsequent incorporation. Half of the replicates of each application treatment were treated with the nitrification inhibitor 3,4-dimethyl pyrazole phosphate (DMPP). Emissions of the greenhouse gases (GHGs) CO2, N2O and CH4 were monitored during 51 days of incubation. Deeper injection (20 cm) did not lead to different GHG emissions compared with a shallow injection (15 cm). Application of DMPP decreased cumulative N2O emissions significantly by 17–70%. DMPP inhibited N2O fluxes and NO3- production, suggesting a positive effect of DMPP on the mitigation of direct GHG emission and nitrate leaching at least during several weeks after digestate fertilization. The effect of DMPP is independent of the application technique.  相似文献   

13.
Injection of slurry or digestate below maize seeds is a relatively new technique developed to improve nitrogen use efficiency. However, this practice has the major drawback of increasing nitrous oxide (N2O) emissions. The application of a nitrification inhibitor (NI) is an effective method to reduce these emissions. To evaluate the effect of the NI 3,4‐dimethypyrazole phosphate (DMPP) on N2O emissions and the stabilization of ammonium, a two‐factorial soil‐column experiment was conducted. PVC pipes (20 cm diameter and 30 cm length) were used as incubation vessels for the soil‐columns. The trial consisted of four treatments in a randomized block design with four replications: slurry injection, slurry injection + DMPP, digestate injection, and digestate injection + DMPP. During the 47‐day incubation period, N2O fluxes were measured twice a week and cumulated by linear interpolation of the gas‐fluxes of consecutive measurement dates. After completion of the gas flux measurement, concentration of ammonium and nitrate within the soil‐columns was determined. DMPP delayed the conversion of ammonium within the manure injection zone significantly. This effect was considerably more pronounced in treatment digestate + NI than in treatment slurry + NI. Regarding the cumulated N2O emissions, no difference between slurry and digestate treatments was determined. DMPP reduced the release of N2O significantly. Transferring the results into practice, the use of DMPP is a promising way to reduce greenhouse gas emissions and nitrate leaching, following the injection of slurry or digestate.  相似文献   

14.
As global warming intensifies, the soil environment in middle to high latitudes will undergo more extensive and frequent freeze–thaw cycles (FTCs), which will significantly affect the carbon and nitrogen cycles of soil ecosystems and aggravate greenhouse gas (GHG) emissions. Biochar can increase soil organic carbon storage and mitigate climate change. To effectively control GHG emissions, soil supplemented with biochar at different application rates (0%, 2%, 4% and 6% [w/w]) under different numbers of FTCs (0, 3, 6, 9, and 12) was selected as the research object. The soil GHG emission characteristics in different experimental treatments and their relationships with soil physical and chemical properties were determined. Our results showed that N2O and CO2 emissions were promoted during FTCs, with values of 3.13–50.37 and 16.22–135.50 μg m−2 h−1, respectively. The order of N2O and CO2 emissions with respect to biochar application rate was as follows: 2% > 0% > 4% > 6%. CH4 emissions were negative during FTCs, varying from −1.62 to −10.59 μg m−2 h−1, and negative CH4 emissions were promoted by biochar. Correlation analysis showed that N2O, CO2 and CH4 emissions were significantly correlated with pH, soil moisture and soil organic matter (SOM), total nitrogen (TN) and NH 4 + –N contents (p < .01). The conceptual path model demonstrated that GHG emissions were significantly influenced by FTCs, moisture, SOM and biochar application rate. Our results indicate that the effects of FTCs on GHG emissions were greater than those of biochar application. Biochar application rates of 4% or 6% should be considered in the future to reduce soil GHG emissions in the black soil region of Northeast China. Our results can help provide a theoretical basis and effective strategy to reduce soil GHG emissions during FTCs in seasonally frozen regions.  相似文献   

15.
Anaerobic digestion of animal manure and crop residues may be employed to produce biogas as a climate-neutral source of energy and to recycle plant nutrients as fertilizers. However, especially organic farmers are concerned that fertilizing with the digestates may impact the soil microbiota and fertility because they contain more mineral nitrogen (N) and less organic carbon (C) than the non-digested input materials (e.g. raw animal slurry or fresh plant residues). Hence, an incubation study was performed where (1) water, (2) raw cattle slurry, (3) anaerobically digested cattle slurry/maize, (4) anaerobically digested cattle slurry/grass-clover, or (5) fresh grass-clover was applied to soil at arable realistic rates. Experimental unites were sequentially sampled destructively after 1, 3 and 9 days of incubation and the soil assayed for content of mineral N, available organic C, emission of CO2 and N2O, microbial phospholipid fatty acids (biomass and community composition) and catabolic response profiling (functional diversity). Fertilizing with the anaerobically digested materials increased the soil concentration of NO3− ca. 30–40% compared to when raw cattle slurry was applied. Grass-clover contributed with four times more readily degradable organic C than the other materials, causing an increased microbial biomass which depleted the soil for mineral N and probably also O2. Consequently, grass-clover also caused a ∼10 times increase in emissions of CO2 and N2O greenhouse gasses compared to any of the other treatments during the 9 days. Regarding microbial community composition, grass-clover induced the largest changes in microbial diversity measures compared to the controls, where raw cattle slurry and the two anaerobically digested materials (cattle slurry/maize, cattle slurry/grass-clover) only induced minor and transient changes.  相似文献   

16.
Applying biochar to soil is an easy way to sequester carbon in soil, while it might reduce greenhouse gas (GHG) emissions and stimulate plant growth. The effect of charcoal application (0, 1.5, 3.0 and 4.5%) on GHG emission was studied in a wastewater sludge-amended arable soil (Typic Fragiudepts) cultivated with wheat (Triticum spp. L.) in a greenhouse. The application of charcoal at ≥1.5% reduced the CO2 emission rate significantly ≥37% compared to unamended soil (135.3 g CO2 ha−1 day−1) in the first two weeks, while the N2O emission rate decreased 44% when 4.5% charcoal was added (0.72 g N2O ha−1 day−1). The cumulative GHG emission over 45 days was 2% lower when 1.5% charcoal, 34% lower when 3.0% charcoal and 39% lower when 4.5% charcoal was applied to the sludge-amended soil cultivated with wheat. Wheat growth was inhibited in the charcoal-amended soil compared to the unamended soil, but not yields after 135 days. It was found that charcoal addition reduced the emissions of N2O and CO2, and the cumulative GHG emissions over 45 days, without altering wheat yield.  相似文献   

17.
Soil cultivation changes and usage of agricultural wastes can have profound impacts on greenhouse gas (GHG) emission from soil. In this study, the effects of soil cultivation and organic amendment on GHG emission were investigated using aerobic incubation. Surface soil (0–20 cm) from (1) rice–legume consecutive rotation (Rice) and (2) recently (<3 years) converted from rice field to plastic-covered intensive vegetable and flower production (VegC) were collected in Kunming, P.R. China. Rose (Rosa rugosa Thunb.) residues and cattle manure were applied at 5% by weight. Results indicated that N2O and CO2 fluxes were significantly influenced by soil cultivation, organic amendment, incubation time and their interaction (p <0.05). Applying cattle manure increased, while rose residue decreased, cumulative N2O emissions from soil (84 days). Rose residue application significantly increased cumulative CO2 emissions with peak values of 6371 (Rice) and 7481 mg kg?1 (VegC), followed by cattle manure addition figure of 2265 (VegC) and 3581 mg kg?1 (Rice). Both were significantly higher (p <0.05) than the un-amended Control at 709 (VegC) and 904 mg kg?1 (Rice). Our study demonstrates that a low C/N ratio in cattle manure is better than a high C/N ratio in rose residue in regard to reducing the global warming potential of agricultural soil.  相似文献   

18.
We determined N2O fluxes from an unfertilized control (CON), from a treatment with mineral N‐fertilizer (MIN), from cattle slurry with banded surface application and subsequent incorporation (INC), and from slurry injection (INJ) to silage maize (Zea mays, L.) on a Haplic Luvisol in southwest Germany. In both years, amount of available N (total N fertilized + Nmin content before N application) was 210 kg N ha?1. In the slurry treatment of the 1st year, 140 kg N ha?1 were either injected or incorporated, whereas 30 kg N ha?1 were surface applied to avoid destruction of the maize plants. In the 2nd year, all fertilizers were applied with one single application. We calculated greenhouse gas emissions (GHG) on field level including direct N2O emissions (calculated from the measured flux rates), indirect N2O emissions (NH3 and NO 3 - induced N2O emission), net CH4 fluxes, fuel consumption and pre‐chain emissions from mineral fertilizer. NH3 losses were measured in the 2nd year using the Dräger‐Tube Method and estimated for both years. NH3 emission was highest in the treatment without incorporation. It generally contributed less than 5% of the greenhouse gas (GHG) emission from silage maize cultivation. The mean area‐related N2O emission, determined with the closed chamber method was 2.8, 4.7, 4.4 and 13.8 kg N2O‐N ha?1 y?1 for CON, MIN, INC, and INJ, respectively. Yield‐related N2O emission showed the same trend. Across all treatments, direct N2O emission was the major contributor to GHG with an average of 79%. Trail hose application with immediate incorporation was found to be the optimum management practice for livestock farmers in our study region.  相似文献   

19.
Increasing organic carbon (OC) stocks in soils reduce atmospheric CO2, but may also cause enhanced N2O emissions. The objective of this study was to determine whether there are any differences in N2O and CO2 emissions from sandy arable soils with different soil OC and total nitrogen stocks due to the annual application of either farmyard manure (S-FYM) or mineral fertilizer (S-MIN) over 27 years. A laboratory incubation was performed to test the short-term effects of the application of different fertilizers [farmyard manure (FYM), KNO3 (MIN) and biogas waste (BW)] on N2O and CO2 emissions. The CO2 emission rates indicated that OC availability in the soil was higher after BW application than after FYM application. N2O emission for 53 days following fertilizer application amounted to 0.01% (MIN), 0.21% (FYM) and 24% (BW) of the total amount of N applied. The high emissions induced by BW were attributed to the combination of a high availability of OC and ammonium in the fermented waste. Fertilization history, which caused higher soil OC stocks in S-FYM, did not influence N2O emissions. The results suggest that characterization of C and N pools in organic fertilizers is required to assess their impact on N2O emissions.  相似文献   

20.
Large areas of peatlands in Germany and the Netherlands are affected by drainage and high nitrogen deposition. Sheep grazing is a common extensive management activity on drained peatlands, in particular on nature protection areas. However, input of easily mineralisable material such as sheep excrements could enhance degradation of soil organic carbon (Corg), thereby increasing the effect of these ecosystems on national GHG budgets. Thus, a microcosm experiment on the influence of sheep excreta on GHG emissions from a histic Gleysol with strongly degraded peat was set up. The 15N and 13C stable isotope tracer technique was used to partition sources of CO2 and N2O. Labeled sheep faeces and urine were obtained by feeding enriched material. Undisturbed soil columns were treated with surface application of urine, faeces or mixtures of both in different label combinations to distinguish between direct effects and possible priming effects. Incubation was done under stable temperature and precipitation conditions. Fluxes as well as 15N and 13C enrichment of N2O and CO2, respectively, were measured for three weeks. Addition of sheep excreta increased emission of total CO2 in proportion to the added carbon amounts. There was no CO2 priming in the peat. No effect on CH4 and N2O was observed under the aerobic experimental conditions. The N2O–N source shifted from peat to excreta, which indicates negative priming, but priming was not significant. The results indicate that sheep excreta do not significantly increase GHG emissions from degraded peat soils. Considering the degraded peatland preserving benefits, sheep grazing on peatlands affected by drainage and high nitrogen deposition should be further promoted.  相似文献   

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