共查询到20条相似文献,搜索用时 203 毫秒
1.
Effects of soil variables and season on the production and consumption of nitric oxide in oxic soils 总被引:2,自引:0,他引:2
Summary NO production rates, NO uptake rate constants, NO compensation points, and different soil variables were determined for various soil types and different soil horizons, and checked for mutual correlations. NO production was detected in all, and NO comsuption in most soils tested. Only soils in a very early state of soil genesis showed no NO consumption activity. NO consumption was positively correlated with soil water and NH
4
+
contents. NO production rates were not correlated with any soil variable. Both NO production and NO consumption tended to decrease from the upper organic to the deeper mineral horizons in different climax soils. The seasonal variation of NO production and NO consumption in a calcic cambisol and a luvisol showed highest rates in summer. The rates of NO production and NO consumption were correlated with a few of the soil variables, but showed no uniform, theoretically comprehensible pattern. However, NO production in samples of the calcic cambisol was stimulated by fertilization with NH
4
+
, but not with NO
3
–
and was inhibited by nitrapyrin, indicating that NO was produced by nitrification. NO production made up about 3% of the nitrification rates. In the luvisol, in contrast, NO production was not affected by the addition of NH
4
+
or NO
3
–
. Nitrification was also undetectable in this acidic soil, except for a few patches where NO production was also detected. 相似文献
2.
3.
The NO turnover in soils was measured in two different experimental set-ups, a flow-through system, which is very time-consuming
and needs rather sophisticated equipment, and a closed system using serum bottles. We compared the NO turnover parameters
(NO consumption rate constant, NO production rate, NO compensation concentration) that were measured with both systems in
different soils, under different conditions and in the presence of 10 Pa acetylene to inhibit nitrification. The values of
the NO turnover parameters that were measured with the two systems under oxic conditions were usually comparable. The addition
of acetylene did not affect the NO consumption rate constants of the soils with the exception of soil G1. However, the NO
production rates and the NO compensation concentrations decreased significantly in the presence of acetylene, indicating that
nitrification was the main source of NO in these soils. Only one soil (Bol) showed no nitrifying activity. Increasing soil
moisture content resulted in decreasing NO consumption rate constants and NO production rates. Even at a high soil moisture
content of 80% water holding capacity, nitrification was the main source of NO. The values of the NO turnover parameters that
were measured with the two systems were not comparable under anoxic conditions. The NO consumption rate constants and the
NO production rates were much lower in the closed than in the flow-through system, indicating that the NO consumption activity
became saturated by the high NO concentrations accumulating in the closed system. Under oxic conditions, however, closed serum
bottles were a cheap, easy and reliable tool with which to determine NO turnover parameters and to distinguish between nitrification
and denitrification as sources of NO.
Received: 21 April 1998 相似文献
4.
Junbao Yu Franz X. Meixner Weidong Sun Guoping Wang Chuanhai Xia 《Soil biology & biochemistry》2010,42(10):1784-1792
Nitric oxide (NO) is an important component of biogeochemical cycling of nitrogen, produced via biologically mediated processes of nitrification and denitrification in soils. The production and consumption processes of NO in black soils are not fully understood. We established how moisture and temperature affect NO dynamics for black soil samples of maize land in the temperate zone of northeastern China. The optimum soil moisture for the maximum NO production and emission was determined to be 41% water-filled pore space (WFPS), based on laboratory experiments and modeling. For a given moisture, NO fluxes increased exponentially with soil temperature at any given soil moisture. The optimum soil moisture for the maximum NO emission was constant and independent of soil temperature. The NO consumption rate constant (k) in the studied soil (range 9.31 × 10−6-15.1 × 10−6 m3 kg−1 s−1) was in the middle of the range of similar k values published to date. The maximum NO emission potential for black soils at 25 °C and 15 °C were about 18.6 and 9.0 ng N m−2 s−1, respectively. Based on laboratory results and field monitoring data of soil water content and soil temperature, the average NO fluxes from black soils in the region were estimated to be 10.7 ng N m−2 s−1 for an entire plant growth period. NO emissions likely occur principally in July, associated with optimum soil moisture. The present study suggests that NO fluxes from black soil are much lower than the previous reports from cropland in southern parts of China. 相似文献
5.
The kinetics of nitric oxide consumption in four tropical soils were studied under oxic and anoxic conditions in a flow-through
system in the laboratory. Under anoxic conditions the soils had a very high affinity for NO, resulting in K
M values of 0.02–0.27 ppmv NO (equivalent to 0.04–0.50 nM NO in the aqueous phase). These K
M values were lower than literature values for NO consumption by denitrifying bacteria. Under oxic conditions the kinetics
of NO consumption in the tropical soils were completely different, exhibiting K
M values higher than 1.7 ppmv. These higher K
M values were similar to literature values for NO consumption by aerobic heterotrophic bacteria. Thus, the tropical soils studied
seem to contain two different NO consumption activities which can be distinguished by their kinetics and which predominate
under aerobic and anaerobic conditions, respectively. However, it was not possible to quantify the contribution of each process
to total NO consumption under natural conditions. Under aerobic conditions NO turnover kinetics were positively correlated
with soil respiration, N mineralisation and soil organic carbon, whereas under anaerobic conditions they were positively correlated
with potential and actual denitrification rates and pH.
Received: 26 September 1996 相似文献
6.
Soils are the dominant sink in the global budget of atmospheric H2, and can be an important local source of atmospheric CO. In order to understand which soil characteristics affect the rates
of H2 consumption and CO production, we measured these activities in 16 different soils at 30% and 60% of their maximum water holding
capacity (whc). The soils were obtained from forests, meadows and agricultural fields in Germany and exhibited different characteristics
with respect to texture, pH, total C, substrate-induced respiration (SIR), respiration, total and inorganic N, N mineralization,
nitrification, N2O production and NO turnover. The H2 consumption rate constants were generally lower at 60% than at 30% whc, whereas the CO production rates were not influenced
by the whc. Spearman correlation analysis showed that H2 consumption correlated significantly (r>0.5, P<0.05) at both water contents only with SIR and potential nitrification. The correlation with these variables that are largely
dominated by soil microorganisms is consistent with our understanding that atmospheric H2 is oxidized by soil hydrogenases. Multiple regression analysis and factor analysis gave similar results. Production of CO,
on the other hand, was significantly correlated to soil total C, respiration, total N and NH4
+. The correlation with these variables that are largely dominated by a soil's chemical composition is consistent with our
understanding that CO is produced by chemical oxidation of soil organic C. CO production was also influenced by soil usage,
with rates increasing in the order: arable<meadow<forest. H2 consumption was not influenced by soil usage.
Received: 28 October 1999 相似文献
7.
8.
9.
Hannu T. Koponen Claudia Escudé Duran Jyrki Hytönen 《Soil biology & biochemistry》2006,38(7):1779-1787
Both NO and N2O are produced in soil microbial processes and have importance in atmospheric physics and chemistry. In recent years several studies have shown that N2O emissions from organic soils can be high at low temperatures. However, the effects of low temperature on NO emissions from soil are unknown. We studied in laboratory conditions, using undisturbed soil cores, the emissions of NO and N2O from organic soils at various temperatures, with an emphasis on processes and emissions during soil freezing and thawing periods. We found no soil freezing- or thawing-related emission maxima for NO, while the N2O emissions were higher both during soil freezing and thawing periods. The results suggest that different factors are involved in the regulation of NO and N2O emissions at low temperatures. 相似文献
10.
Temperature dependence of nitrification,denitrification, and turnover of nitric oxide in different soils 总被引:2,自引:0,他引:2
Summary The temperature dependence of the NO production rate and the NO consumption rate constant was measured in an Egyptian soil, a soil from the Bavarian Forest, and a soil from the Donau valley, together with the temperature dependence of the potential rates of ammonium oxidation, nitrite oxidation, and denitrification, and the temperature dependence of the growth of NH
inf4
sup+
-oxidizing, NO
inf2
sup-
-oxidizing, and NO
inf3
sup-
-reducing bacteria in most probable number assays. In the acidic Bavarian Forest soil, NO production was only stimulated by the addition of NO
inf3
sup-
but not NH
inf4
sup+
. However, NO production showed no temperature optimum, indicating that it was due to chemical processes. Most probable numbers and potential activities of nitrifiers were very low. NO consumption, in contrast, showed a temperature optimum at 25°C, demonstrating that consumption and production of NO were regulated individually by the soil temperature. In the neutral, subtropical Egyptian soil, NO production was stimulated only by the addition of NH
inf4
sup+
but not NO
inf3
sup-
. All activities and most probable numbers showed a temperature optimum at 25° or 30°C and exhibited apparent activation energies between 61 and 202 kJ mol-1. However, a few nitrifiers and denitrifiers were also able to grow at 8° or 50°C. Similar temperature characteristics were observed in the Donau valley soil, although it originated from a temperate region. In this soil NO production was stimulated by the addition of NH
inf4
sup+
or of NO
inf3
sup-
. Both NO production and consumption were stimulated by drying and rewetting. 相似文献
11.
Purpose
Two recent discoveries in nitrogen (N) cycling processes, i.e., archaeal ammonia oxidizers and anaerobic ammonia (ammonium) oxidation (anammox), have triggered great interest in studying microbial ammonia oxidation processes. The purpose of this review is to highlight recent progress in ammonia oxidation processes in soils and sediments and to propose future research activities in this topic.Results and discussion
Aerobic ammonia oxidation and anammox processes are linked through the production and consumption of nitrite, respectively, thereby removing the reactive N (NH4 +, NO2 ?, NO3 ?) from soil and sediment ecosystems. Ammonia-oxidizing microorganisms are widely distributed in soils and sediments, and increasing evidence suggests that ammonia-oxidizing archaea and bacteria are functionally dominant in the ammonia oxidation of acid soils and other soils, respectively. The widespread occurrence and great variation in the abundance of anammox bacteria indicate their heterogeneous distribution and niche differentiation. Therefore, the worldwide distribution of both microbial groups in nature has stimulated researchers to investigate the physiology and metabolism of related groups, as well as appraising their contribution to N cycling.Conclusions
We summarized the current progress and provided future perspectives in the microbiology of aerobic and anaerobic ammonia oxidation in soils and sediments. With increasing concern and interest in soil and sediment ammonia oxidation processes, studies in the microbial mechanisms underlying nitrification and anammox, as well as their interactions, are essential for understanding their contribution to the loss of N either through nitrate leaching or N-related gas emissions. 相似文献12.
Soils are a major source of atmospheric NO and N2O. Since the soil properties that regulate the production and consumption of NO and N2O are still largely unknown, we studied N trace gas turnover by nitrification and denitrification in 20 soils as a function
of various soil variables. Since fertilizer treatment, temperature and moisture are already known to affect N trace gas turnover,
we avoided the masking effect of these soil variables by conducting the experiments in non-fertilized soils at constant temperature
and moisture. In all soils nitrification was the dominant process of NO production, and in 50% of the soils nitrification
was also the dominant process of N2O production. Factor analysis extracted three factors which together explained 71% of the variance and identified three different
soil groups. Group I contained acidic soils, which showed only low rates of microbial respiration and low contents of total
and inorganic nitrogen. Group II mainly contained acidic forest soils, which showed relatively high respiration rates and
high contents of total N and NH4
+. Group III mainly contained neutral agricultural soils with high potential rates of nitrification. The soils of group I produced
the lowest amounts of NO and N2O. The results of linear multiple regression conducted separately for each soil group explained between 44–100% of the variance.
The soil variables that regulated consumption of NO, total production of NO and N2O, and production of NO and N2O by either nitrification or denitrification differed among the different soil groups. The soil pH, the contents of NH4
+, NO2
– and NO3
–, the texture, and the rates of microbial respiration and nitrification were among the important variables.
Received: 28 October 1999 相似文献
13.
For this century, an increasing frequency of extreme meteorological boundary conditions is expected, presumably resulting in a changing frequency of freezing and thawing of soils in higher‐elevation areas. Our current knowledge about the effects of these events on trace‐gas emissions from soils is scarce. In this study, the effects of freeze–thaw events on the fluxes of the trace gases CO2, N2O, and NO between soil and atmosphere were investigated in a laboratory experiment. Undisturbed soil columns were collected from a mature Norway spruce forest in the “Fichtelgebirge”, SE Germany. The influence of freezing temperatures (–3°C, –8°C, –13°C) on gas fluxes was studied during the thawing periods (+5°C) in three freeze–thaw cycles (FTCs) and compared to unfrozen controls (+5°C). Two different types of soil columns were examined in parallel—one consisting of O layer only (O columns) and one composed of O layer and mineral soil horizons (O+M columns)—to quantify the contribution of the organic layer and the top mineral soil to the production or consumption of these trace gases. During the thawing period, we observed increasing emissions of CO2, N2O, and NO from the spruce forest soil, but the cumulative emissions of these gases did mostly not exceed the level of the controls. The results show that the O layers were mainly involved in the gas production. Severe soil frost increased CO2 fluxes during soil thawing, whereas repetition of the freeze–thaw events decreased CO2 fluxes from the thawing soil. Fluxes of N2O and NO were neither influenced by freezing temperature nor by freeze–thaw repetition. Stable‐isotope analysis indicated that denitrification was mostly responsible for the N2O production in the FTC columns. Furthermore, isotope data demonstrated a consumption of N2O through microbial denitrification to N2. It was further shown, that production of N2O also occurred in the mineral horizons. The NO emissions were mainly driven by increasing soil temperature during thawing. In this freeze–thaw experiment up to 20 times higher NO than N2O fluxes were recorded. Our results suggest that topsoil thawing has little potential to increase the emissions of CO2, N2O, and NO in spruce forest soils. 相似文献
14.
羟胺(NH_2OH)和亚硝态氮(NO_2~--N)均可以通过非生物过程产生N_2O,但是同一土壤中其对N_2O排放的相对贡献尚不明确。本文采用高压灭菌和室内培养方法,测定了采自6个不同地点的农业利用土壤在灭菌和非灭菌条件下添加NH_2OH或NO_2~--N后N_2O的排放量,以研究土壤中NH_2OH和NO_2~--N非生物过程对N_2O排放的相对贡献及其关键因子。结果表明,供试土壤中,NH_2OH非生物过程产生的N_2O贡献介于6%~73%,NO_2~--N非生物过程产生N_2O占的比例为3%~236%;在pH7的衢州茶园、鹰潭旱地、常熟菜地和海伦旱地土壤中,添加NO_2~--N后非生物过程产生N_2O比例大于添加NH_2OH的处理,但是在pH7的常熟果园和封丘旱地土壤中则相反;pH是影响NH_2OH和NO_2~--N非生物过程产生N_2O的关键因子,添加NH_2OH处理中非生物过程产生N_2O占N_2O总排放量的比例与土壤pH呈正相关(p0.05),而在添加NO_2~--N处理中呈负相关(p0.01)。上述结果说明,NO_2~--N在偏酸性土壤中可能主要通过非生物过程产生N_2O,而在偏碱性土壤中主要通过生物过程;NH_2OH则与之相反。 相似文献
15.
Summary NO and N2O release rates were measured in an acidic forest soil (pH 4.0) and a slightly alkaline agricultural soil (pH 7.8), which were incubated at different O2 concentrations (<0.01 – 20% O2) and at different NO concentrations (40 – 1000 ppbv NO). The system allowed the determination of simultaneously operating NO production rates and NO uptake rate constants, and the calculation of a NO compensation concentration. Both NO production and NO consumption decreased with increasing O2. NO consumption decreased to a smaller extent than NO production, so that the NO compensation concentrations also decreased. However, the NO compensation concentrations were not low enough for the soils to become a net sink for atmospheric NO. The release of N2O increased relative to NO release when the gases were allowed to accumulate instead of being flushed out. The forest soil contained only denitrifying, but not nitrifying bacteria, whereas the agricultural soil contained both. Nevertheless, NO release rates were less sensitive to O2 in the forest soil compared to the agricultural soil. 相似文献
16.
Nitrification and denitrification are, like all biological processes, influenced by temperature. We investigated temperature
effects on N trace gas turnover by nitrification and denitrification in two soils under two experimental conditions. In the
first approach ("temperature shift experiment") soil samples were preincubated at 25 °C and then exposed to gradually increasing
temperatures (starting at 4 °C and finishing at 40–45 °C). Under these conditions the immediate effect of temperature change
was assessed. In the second approach ("discrete temperature experiment") the soil samples were preincubated at different temperatures
(4–35 °C) for 5 days and then tested at the same temperatures. The different experimental conditions affected the results
of the study. In the temperature shift experiment the NO release increased steadily with increasing temperature in both soils.
In the discrete temperature experiment, however, the production rates of NO and N2O showed a minimum at intermediate temperatures (13–25 °C). In one of the soils (soil B9), the percent contribution of nitrification
to NO production in the discrete temperature experiment reached a maximum (>95% contribution) at 25 °C. In the temperature
shift experiment nitrification was always the dominant process for NO release and showed no systematic temperature dependency.
In the second soil (soil B14), the percent contribution of nitrification to NO release decreased from 50 to 10% as the temperature
was increased from 4 °C to 45 °C, but no differences were evident in the discrete temperature experiment. The N2O production rates were measured in the discrete temperature experiment only. The contribution of nitrification to N2O production in soil B9 was considerably higher at 25–35 °C (60–80% contribution) than at 4–13 °C (15–20% contribution).
In soil B14 the contribution of nitrification to N2O production was lowest at 4 °C. The effects of temperature on N trace gas turnover differed between the two soils and incubation
conditions. The experimental set-up allowed us to distinguish between immediate effects of short-term changes in temperature
on the process rates, and longer-term effects by which preincubation at a particular temperature presumably resulted in the
adaptation of the soil microorganisms to this temperature. Both types of effects were important in regulating the release
of NO and N2O from soil.
Received: 20 October 1998 相似文献
17.
设施菜田土壤pH和初始C/NO3– 对反硝化产物比的影响 总被引:1,自引:0,他引:1
18.
戴云山自然保护区森林土壤氮转化特点研究 总被引:3,自引:1,他引:2
利用~(15)N稳定同位素成对标记法并结合MCMC数值模型,研究了戴云山国家级自然保护区天然毛竹林(BF)及其邻近黄山松–杉木林(NF)土壤氮素初级转化速率,以评估该地区森林生态系统土壤氮状态,并分析其保氮机制。结果表明:BF土壤NH_4~+-N的总产生速率(以N量计,13.16μg/(g×d))是NF土壤的2倍(6.25μg/(g×d)),其中黏土矿物对NH_4~+-N的解吸作用是BF产生NH_4~+-N的主要过程(55%),而NF主要以有机氮的矿化作用为主(56%)。BF土壤氮素初级矿化速率为5.56μg/(g×d),显著高于NF的3.40μg/(g×d)。土壤氮素初级矿化速率与土壤全氮含量显著正相关(P0.05),而与C/N比表现显著负相关(P0.05)。BF与NF土壤NH_4~+-N总产生量的90%均被土壤微生物的同化作用以及黏土矿物的吸附作用所消耗。两种土壤的硝化作用微弱,BF土壤总硝化速率(以N量计,0.23μg/(g×d))与NF土壤(0.26μg/(g×d))相差不大。两种林地土壤硝化作用均以有机氮的异养硝化为主,自养硝化过程可忽略不计。BF与NF土壤中NO_3~–-N消耗速率均超过了产生速率,表明BF与NF土壤均能有效降低NO_3~–-N的潜在淋失风险,其中BF土壤中NO_3~–-N的消耗以微生物的同化作用为主(58%),而NF土壤以NO_3~–-N异化还原为NH_4~+-N过程为主(68%)。戴云山国家级自然保护区两种亚热带森林土壤的氮转化过程均以NH_4~+-N转化为主,产生的绝大多数NH_4~+-N会迅速通过微生物对NH_4~+-N的同化作用以及黏土矿物对NH_4~+-N的吸附作用固持到有机氮库中;自养硝化过程微弱,使得无机氮主要以NH_4~+-N的形式保存于土壤中,同时酸性土壤环境有效削弱了NH_4~+-N的挥发损失。此外,相对较高的NO_3~–-N微生物同化速率以及异化还原为NH_4~+-N速率,进一步有效降低了NO_3~–-N的淋溶损失以及反硝化作用的气态损失风险,使该地区森林土壤能够在多雨的条件下有效保持氮素,满足植物的生长需求。 相似文献
19.
D. Levanon J. J. Meisinger E. E. Codling J. L. Starr 《Water, air, and soil pollution》1994,72(1-4):179-189
The impact of two tillage systems, plow tillage (PT) and no-tillage (NT), on microbial activity and the fate of pesticides in the 0–5 cm soil layer were studied. The insecticides carbofuran and diazinon, and the herbicides atrazine and metolachlor were used in the study, which included the incubation and leaching of pesticides from untreated soils and soils in which microorganisms had been inhibited. The mineralization of ring14C labeled pesticides was studied. The study differentiated between biotic and abiotic processes that determine the fate of pesticides in the soil. Higher leaching rates of pesticides from PT soils are explaned by the relative importance of each of these processes. In NT soils, higher microbial populations and activity were associated with higher mineralization rates of atrazine, diazinon and carbofuran. Enhanced transformation rates played an important role in minimizing the leaching of metolachlor and carbofuran from NT soils. The role of abiotic adsorption/retention was important in minimizing the leaching of metolachlor, carbofuran and atrazine from NT soils. The role of fungi and bacteria in the biodegradation process was studied by selective inhibition techniques. Synergistic effects between fungi and bacteria in the degradation of atrazine and diazinon were observed. Carbofuran was also degraded in the soils where fungi were selectively inhibited. Possible mechanisms for enhanced biodegradation and decreased mobility of these pesticides in the upper layer of NT soils are discussed. 相似文献
20.
生境因子作用下NO_3~-/NH_4~+吸收及硝酸还原酶活性变化 总被引:1,自引:0,他引:1
土壤中的氮素因土壤类型和季节变化产生异质性。在长期的进化过程中,植物适应各自的氮营养生境,形成了对NO3-/NH4+吸收的分子机制。饱和高亲和传输系统(HATS)中,植物在不同的转录基因控制下吸收NO3-/NH4+,表现出对两种氮源的偏选性。这种偏选性主要取决于植物种的特性,但是NO3-/NH4+的吸收受光照、介质N强度、pH值、外源氨基酸和温度等生境因子的影响,同时植物的营养生境也因NO3-/NH4+的吸收被深刻改造。硝酸还原酶(NR)在氮同化过程中作用于NO3-还原阶段,其活性受各种生境因子的制约,影响植物对NO3-吸收利用。 相似文献