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1.
Abstract

Importance of agricultural practices for greenhouse gases mitigation is examined worldwide. However, there is no consensus on CO2 emissions as affected by soil management practices. Deeper understanding of soil CO2 fluxes and drivers under different management practices are needed. The investigation of net CO2 exchange rate as dependent variable and drivers (soil water and temperature, air temperature) as affected by soil type (loam and sandy loam), tillage (conservation and no-tillage) and fertilization are presented.

Soil management practices and weather conditions affected the CO2 flux through effects on soil water and temperature regime. Mean net CO2 exchange rate on sandy loam was 8% higher than on loam. No-tillage, as a moisture-conserving tool, could be an appropriate tool for CO2 emissions mitigation in any weather conditions on sandy loam; however, the advantage of no-tillage on loam was negligible. Mineral NPK fertilizers promoted significantly higher net CO2 exchange rate in both soils, but suppressed it by 15% on sandy loam during a normal year. Effect of soil water content on net CO2 exchange rate was direct in all tillage and fertilization treatments in both loam and sandy loam, whereas this effect was positive only in dry and normal weather conditions. In wet weather conditions, the direct effect of soil water content on net CO2 exchange rate was negative. Soil and air temperature acted indirectly on net CO2 exchange rate. The increase in temperature markedly suppressed the positive direct impact of soil water content on net CO2 exchange rate in dry weather conditions, but did not reduce the direct effect of soil water content in normal weather conditions. In a wet year the negative indirect effect of increased temperature enhanced the negative direct impact of soil water surplus on net CO2 exchange rate.  相似文献   

2.
Summary Trenching was used to reduce root activity in treeless plots in a New Mexico mixed-conifer forest to examine the effects of plant roots on soil processes. Trenching led to increases in moisture content (104%), inorganic N concentration (115%), and mass loss from cellulose (196%). In laboratory incubations, trenched soils collected in the 1st and 2nd year after trenching evolved 52% and 115% more CO2, respectively, than control soils. Amending incubated trenched and control soils with moisture and inorganic N indicated that increased soil moisture content in trenched plots could explain the increased microbial activity. Trenching also had statistically significant but inconsistent effects on net N mineralization in incubated soils. The greatest effect of trenching was to increase net N mineralization under favorable temperature and moisture conditions. Irrigation of field plots increased both CO2 evolution and net N mineralization. Overall, these data are consistent with the hypothesis that plant roots reduced microbial activity by moisture uptake during the time of the study.  相似文献   

3.
土壤呼吸排放是陆地生态系统土气交换快速而活跃的途径之一,对大气CO2浓度的变化有显著的影响。本文对太湖地区一个代表性水稻土水稻收割后土壤基底呼吸CO2排放进行了昼夜观测和采样分析。结果表明,不同小区平均土壤呼吸与CO2排放速率在CO2-C.12.2～25.2.mg/(m2h)之间,日排放量在CO2-C.327.2～604.1mg/(m2d)之间,低于文献报道的森林和草地及旱作农田的土壤呼吸;与长期有机-无机配施处理相比,长期单施化肥CO2日排放量提高了55%～85%,并且显著提高了土壤呼吸对土壤(5.cm)温度的响应敏感性。相关分析表明,土壤呼吸CO2排放强度与土壤微生物N(Nmic)、微生物C∶N(Cmic/Nmic)和P的有效性有密切的关系;生物有效N和P的有效性显著地影响着土壤呼吸与CO2的生成和排放。本试验结果进一步支持了水稻土的固碳效应。但是,供试不同小区土壤呼吸排放强度的变异隐含着长期不同施肥处理可能使与高呼吸活性有关的微生物群落发生改变,有待于进一步研究。  相似文献   

4.
The effects of soil mesofauna and different farming systems on decomposition of clover (Trifolium repens) litter were investigated in a laboratory experiment. Microcosms were incubated for 16 weeks with fine and coarse litterbags in soils from three types of management systems: fallow, integrated farming and organic farming, the latter two cropped with wheat. The effects were studied by analysing litter mass loss, C and N content, DOC, nitrate and pH in soil leachate, and CO2 production, as well as mesofauna. Mesofauna significantly accelerated mass loss and C and N release from clover litter in all three soils. With mesofauna access, at the end of the experiment average clover mass loss was almost twice as high and clover C and N content were 60% lower than without mesofauna. Farming systems influenced the decomposition through affecting both element turnover and mesofauna. Although in the first weeks less N was leached from organic farming than from integrated farming soil, cumulative N leaching did not differ between these soils. However, more than 20% less N was leached from the fallow soil than from the field soils. CO2 production was highest in fallow soil. Here, mesofauna had no effect on this variable. In soil with integrated farming, mesofauna reduced cumulative CO2 production by 10% whereas in soil from organic farming it increased CO2 production by 20%. Our data suggest that differences in C and N turnover in different management systems are strongly mediated by soil mesofauna.  相似文献   

5.
The impact of horticultural management on carbon sequestration in soils has been limited so far to tillage and nitrogen fertilization. Our objective was to evaluate by mathematical modeling the effect of potassium fertilization on CO2 binding in cropland soils. The developed model integrates three subunits: (1) A published simulator of crop dry‐matter (DM) production in response to N, P, K fertilization, but not DM partitioning; (2) a published soil–crop–atmosphere model predicting crop yield and DM partitioning as a function of N but not K fertilization; (3) an original model computing the organic‐inorganic carbon transformations, inorganic‐carbon reactions and transport in soil, CO2 diffusion, and soil carbon sequestration. The model described the K‐fertilization effect on C binding in soil as a function of the soil pH, the Ca2+ concentration in the soil solution, hydraulic properties, air temperature, and crop DM production, and partitioning characteristics. In scenarios of corn (Zea mays L.) growth in clayey soil and wheat (Triticum aestivum L.) in loam soil, the computed K‐induced CO2 sequestration amounted to ≈ 14.5 and 24 kg CO2 (kg K)–1, respectively (0 vs. 100 kg ha–1 K application). The soil CO2 sequestration declined by 8% when corn grew in sandy instead of clayey soil and by 20% when the temperature was 10°C higher than the temperature prevailing in mild semiarid zones. All predicted CO2‐sequestration results were approximately 30‐fold higher than the 0.6 kg CO2 emitted per kg of K manufactured in industry.  相似文献   

6.
Net carbon dioxide (CO2) emission from soils is controlled by the input rate of organic material and the rate of decomposition which in turn are affected by temperature, moisture and soil factors. While the relationships between CO2 emission and soil factors are well-studied in non-salt-affected soils, little is known about soil properties controlling CO2 emission from salt-affected soils. To close this knowledge gap, non-salt-affected and salt-affected soils (0-0.30 m) were collected from two agricultural regions: in India (irrigation induced salinity) and in Australia (salinity associated with ground water or non-ground water associated salinity). A subset (50 Indian and 70 Australian soils) covering the range of electrical conductivity (EC) and sodium adsorption ratio (SAR) in each region was used in a laboratory incubation experiment. The soils were left unamended or amended with mature wheat residues (2% w/w) and CO2 release was measured over 120 days at constant temperature and soil water content. Residues were added to overcome carbon limitation for soil respiration. For the unamended soils, separation in multidimensional scaling plots was a function of differences in soil texture (clay, sand), SOC pools (particulate organic carbon (POC) and humus-C) and also EC. Cumulative CO2-C emission from unamended and amended soils was related to soil properties by stepwise regression models. Cumulative CO2-C emission was negatively correlated with EC in saline soils (R2 = 0.50, p < 0.05) from both regions. In the unamended non-salt-affected soils, cumulative CO2-C emission was significantly positively related to the content of POC for the Indian soils and negatively related to clay content for the Australian soils. In the wheat residue amended soils, cumulative CO2-C emission had positive relationship with POC and humus-C but a negative correlation with EC for both Indian and Australian soils. SAR was negatively related (β = −0.66, p < 0.05) with cumulative CO2-C emission only for the unamended saline-sodic soils of Australia. Cumulative CO2-C emission was significantly negatively correlated with bulk density in amended soils from both regions. The study showed that in salt-affected soils, EC was the main factor influencing for soil respiration but the content of POC, humus-C and clay were also influential with the magnitude of influence depending on whether the soils were salt affected or not.  相似文献   

7.
Degradation of14C-labeled 2-aminobenzimidazole was measured in sandy loam soils by means of the evolution of14C into CO2. The correlation between soil temperature and 2-AB-degradation was investigated utilizing a temperature gradient incubator for temperatures between 1 and 40°C with a water content of 100% of field capacity. Within the temperature interval 1 to 20°C, the evolution of14C was exponentially related to the inverse of the absolute temperature, in accordance with the Arrhenius' equation. Maximum evolution of14C was at 22°C while between 25 and 35°C the evolution remained almost constant and at 40°C it was almost nil. The correlation between soil water content and 2-AB-degradation was measured at 25°C in air dry soil and with water contents varying from 5 to 41% (equivalent to 28 to 227% of field capacity (FC)). From 28 to 94% of FC an exponential increase in the evolution of14C was observed while the evolution was slightly decreasing in soil with water contents above this level. Degradation of 2-AB in soil was greatly enhanced when the soil was inoculated with liquid or with soil aliquots from a soil perfusion apparatus through which 2-AB had been percolating for 6 mo. This indicates the presence of organisms able to decompose 2-AB in the pre-treated soil and in the perfusing water.  相似文献   

8.
The turnover of native and applied C and N in undisturbed soil samples of different texture but similar mineralogical composition, origin and cropping history was evaluated at −10 kPa water potential. Cores of structurally intact soil with 108, 224 and 337 g clay kg−1 were horizontially sliced and 15N-labelled sheep faeces was placed between the two halves of the intact core. The cores together with unamended treatments were incubated in the dark at 20 °C and the evolution of CO2-C determined continuously for 177 d. Inorganic and microbial biomass N and 15N were determined periodically. Net nitrification was less in soil amended with faeces compared with unamended soil. When adjusted for the NO3-N present in soil before faeces was applied, net nitrification became negative indicating that NO3-N had been immobilized or denitrified. The soil most rich in clay nitrified least N and 15N. The amounts of N retained in the microbial biomass in unamended soils increased with clay content. A maximum of 13% of the faeces 15N was recovered in the microbial biomass in the amended soils. CO2-C evolution increased with clay content in amended and unamended soils. CO2-C evolution from the most sandy soil was reduced due to a low content of potentially mineralizable native soil C whereas the rate constant of C mineralization rate peaked in this soil. When the pool of potentially mineralizable native soil C was assumed proportional to volumetric water content, the three soils contained similar proportions of potentially mineralizable native soil C but the rate constant of C mineralization remained highest in the soil with least clay. Thus although a similar availability of water in the three soils was ensured by their identical matric potential, the actual volume of water seemed to determine the proportion of total C that was potentially mineralizable. The proportion of mineralizable C in the faeces was similar in the three soils (70% of total C), again with a higher rate constant of C mineralization in the soil with least clay. It is hypothesized that the pool of potentially mineralizable C and C rate constants fluctuate with the soil water content.  相似文献   

9.
Studies on earthworms in rice-based ecosystems tend to focus on some pest species, while the potential of these important soil engineers for beneficially affecting carbon storage and cycling is widely ignored. We carried out a microcosm experiment to quantify the impact of the tropical earthworm Pheretima sp. on the C turnover in paddy soils under different conditions of water saturation and N fertilization. The soil was sampled at the lowland farm of the International Rice Research Institute (Philippines). In the absence of earthworms, soil respiration showed a distinct hump-shaped maximum at intermediate levels of water saturation (4-fold higher than in hand-dry soil) and increased 1.5-fold with increasing amounts of N fertilization. Amounts of CH4 emitted, in contrast, were small at low to moderate soil humidity and became very high under conditions of water saturation (80-fold higher than hand-dry soil). No response to nitrogen addition was observed. Earthworms suppressed both the respiration maximum at intermediate saturation levels (by a factor of 1.4) and the stimulating impact of N fertilization (1.7-fold at maximum fertilizer level). On the other hand, earthworms strongly increased CH4 release under conditions of high water saturation (3-fold). No consistent response of the soil microflora (bacterial abundance, soil enzymes) to earthworm activity could be established. Our findings suggest that the stabilization of soil organic C via earthworm bioturbation is confined to the range of soil humidity that allows high activity of Pheretima sp. Under conditions of intensive agriculture, the stabilizing effect of the worms may even be augmented by the fact that they offset the positive effect of N fertilization on microbial respiration. Earthworms may thus play a vital role in reducing the CO2 flush from paddy soils after the conversion to non-flooded crops such as aerobic rice or maize. Acceleration of methane emission in very humid soils nevertheless points to a certain risk that is associated with increasing earthworm abundance in production systems that are still exposed to temporary flooding during the wet season.  相似文献   

10.
A 90‐day laboratory incubation study was carried out using six contrasting subtropical soils (calcareous, peat, saline, noncalcareous, terrace, and acid sulfate) from Bangladesh. A control treatment without nitrogen (N) application was compared with treatments where urea, ammonium sulfate (AS), and ammonium nitrate (AN) were applied at a rate of 100 mg N (kg soil)–1. To study the effect of N fertilizers on soil carbon (C) turnover, the CO2‐C flux was determined at nine sampling dates during the incubation, and the total loss of soil carbon (TC) was calculated. Nitrogen turnover was characterized by measuring net nitrogen mineralization (NNM) and net nitrification (NN). Simple and stepwise multiple regressions were calculated between CO2‐C flux, TC, NNM, and NN on the one hand and selected soil properties (organic C, total N, C : N ratio, CEC, pH, clay and sand content) on the other hand. In general, CO2‐C fluxes were clearly higher during the first 2 weeks of the incubation compared to the later phases. Soils with high pH and/or indigenous C displayed the highest CO2‐C flux. However, soils having low C levels (i.e., calcareous and terrace soils) displayed a large relative TC loss (up to 22.3%) and the added N–induced TC loss from these soils reached a maximum of 10.6%. Loss of TC differed depending on the N treatments (urea > AS > AN >> control). Significantly higher NNM was found in the acidic soils (terrace and acid sulfate). On average, NNM after urea application was higher than for AS and AN (80.3 vs. 71.9 and 70.9 N (kg soil)–1, respectively). However, specific interactions between N‐fertilizer form and soil type have to be taken into consideration. High pH soils displayed larger NN (75.9–98.1 mg N (kg soil)–1) than low pH soils. Averaged over the six soils, NN after application of urea and AS (83.3 and 82.2 mg N (kg soil)–1, respectively) was significantly higher than after application of AN (60.6 mg N (kg soil)–1). Significant relationships were found between total CO2 flux and certain soil properties (organic C, total N, CEC, clay and sand content). The most important soil property for NNM as well as NN was soil pH, showing a correlation coefficient of –0.33** and 0.45***, respectively. The results indicate that application of urea to acidic soils and AS to high‐pH soils could be an effective measure to improve the availability of added N for crop uptake.  相似文献   

11.
The concentrations of CO2 and methane in soil air have been measured in different horizons of the profile of irrigated sierozemic soils of Uzbekistan. The data obtained on a typical sierozem and a meadowsierozemic soil under wheat and cotton fields during different phases of plant growth show that the maximum concentration of CO2 in the soil air is observed at the depth of 60–80 cm. This is explained by the maximum content of roots of winter wheat and cotton in this layer; this is also the layer with the maximum content of microorganisms producing CO2 in the course of microbial respiration. In the regularly irrigated sierozemic soils, anaerobic conditions are formed after irrigation. They favor the development of anaerobic microorganisms producing methane in relatively small amounts. The distribution of methane in the soil air along the soil profile is more even than that of CO2 (the variation coefficients are 0.14 for methane and 0.46 for CO2).  相似文献   

12.
Agricultural peat soils in the Sacramento-San Joaquin Delta, California have been identified as an important source of dissolved organic carbon (DOC) and trihalomethane precursors in waters exported for drinking. The objectives of this study were to examine the primary sources of DOC from soil profiles (surface vs. subsurface), factors (temperature, soil water content and wet-dry cycles) controlling DOC production, and the relationship between C mineralization and DOC concentration in cultivated peat soils. Surface and subsurface peat soils were incubated for 60 d under a range of temperature (10, 20, and 30 °C) and soil water contents (0.3-10.0 g-water g-soil−1). Both CO2-C and DOC were monitored during the incubation period. Results showed that significant amount of DOC was produced only in the surface soil under constantly flooded conditions or flooding/non-flooding cycles. The DOC production was independent of temperature and soil water content under non-flooded condition, although CO2 evolution was highly correlated with these parameters. Aromatic carbon and hydrophobic acid contents in surface DOC were increased with wetter incubation treatments. In addition, positive linear correlations (r2=0.87) between CO2-C mineralization rate and DOC concentration were observed in the surface soil, but negative linear correlations (r2=0.70) were observed in the subsurface soil. Results imply that mineralization of soil organic carbon by microbes prevailed in the subsurface soil. A conceptual model using a kinetic approach is proposed to describe the relationships between CO2-C mineralization rate and DOC concentration in these soils.  相似文献   

13.
The aim of this study was to evaluate experimentally derived temperature functions for the rate coefficients of net N mineralization in sandy arable soils from NW Germany via field measurements. In part I of this paper (Heumann and Böttcher, 2004), different temperature functions for the rate coefficients of a two‐pool first‐order kinetic equation were derived by long‐term laboratory incubations at 3°C to 35°C. In this paper, field net N mineralization during winter of 25 plots was measured in undisturbed soil columns with a diameter of 20 cm to the depth of the Ap horizon. Mean simulated net N mineralization with the most adequate multiple functions corresponded also best with the mean of the measured values despite of an overestimation of about 10%. Distinctly larger deviations under use of other temperature functions (Arrhenius, Q10) were directly related to their deviations from mean, experimentally derived rate coefficients. Simulated net N mineralization in the soil columns was significantly correlated with measured values, regardless of the temperature functions. Yet the goodness of fit was generally relatively low due to the spatial variability of measured net N mineralization within replicate soil columns, although the mean CV (38%) was by far not extraordinary. The pool of slowly mineralizable N contributed considerably to net N mineralization during four to five winter months, on an average 10.0 kg N ha–1, about one third of total simulated N mineralization. Sometimes, it contributed even 21.3 kg N ha–1, which is almost sufficient to reach the EU drinking‐water limit for nitrate in these soils. Simulations with widely used functions that were once derived from loess soils overestimated mineralization from pool Nslow in the studied sandy arable soils by a factor of two.  相似文献   

14.
淡水湿地不同围垦土壤非耕季节呼吸速率差异   总被引：1，自引：0，他引：1  
选择何种湿地利用方式,使得土壤固碳能力及CO2气体排放受到的影响最小,是合理利用湿地、减少温室气体排放的关键所在,湿地土壤呼吸不仅受环境条件的影响,还受土壤本身性状的影响。以皖江地区为研究区域,利用定位试验对天然湿地及不同围垦利用方式下土壤在非耕季节CO2排放通量、大气温度及表层土壤温度进行测定,并对其土壤TOC含量进行分析。结果表明,CO2排放通量:水稻田[700.70 mg/(m2·h)]> 旱地[433.80 mg/(m2·h)]> 天然湿地[302.66 mg/(m2·h)],天然湿地土壤TOC含量明显高于围垦旱地及水稻田(0-30 cm),说明天然湿地较围垦旱地和水稻田对大气中CO2浓度贡献最小,能存储更多的碳。探讨了CO2排放通量与温度的相关性,得出3种土壤类型CO2排放通量与大气温度和表层土壤温度均呈正相关关系。  相似文献   

15.
为研究氮肥施用对玉米根际呼吸和土壤基础呼吸温度敏感性的影响,采用动态密闭气室红外CO2分析法,于2010年进行田间试验,该试验设4个处理：裸地不施氮肥（CK）、裸地施氮肥（CK-N）、种植玉米不施加氮肥（M）、种植玉米施加氮肥（M-N）,观测玉米田土壤呼吸各组分的日变化规律,同时观测土壤温度、气温等环境因子。结果表明,不种植玉米处理（CK和CK-N）土壤呼吸速率（土壤基础呼吸）为0.57～1.23μmol·m-2·s-1,施加氮肥对土壤基础呼吸没有显著影响;种植玉米条件下,施氮处理（M-N）的季节平均土壤呼吸速率为3.14μmol·m-2·s-1,显著高于不施氮处理（M）,增幅达31.9%。CK和CK-N处理的土壤基础呼吸温度敏感系数Q10分别为1.20、1.25,而不施氮和施氮条件下玉米根际呼吸的Q10值则分别为1.27、1.49。施加氮肥导致玉米根际呼吸温度敏感性明显增强（Q10值增大）,而土壤基础呼吸的温度敏感性则无明显变化,两种效应的叠加使得种植玉米土壤的总呼吸速率温度敏感性明显增加。  相似文献   

16.
Fate of inorganic 15N in the profile of different coniferous forest soils   总被引：3，自引：0，他引：3  
The fate of inorganic 15N added to different coniferous forest soils was traced throughout the soil profile (0–25 cm) in a laboratory experiment under controlled conditions of temperature and water content. Six soils with different chemical climates were compared. The sequestration of labelled N was significantly explained by the clay content but the correlation was improved when C and N content were included. The level of acidification, even in soil with a fine texture, reduced the immobilization. For a similar N input, sandy soils with low C content or high acidification showed a reduced N storage capacity, so that N excess would be able to pollute the ground-water.  相似文献   

17.
不同培肥措施下土壤CO2释放及其动力学研究   总被引：7，自引：0，他引：7  
实验室恒温密闭培养法研究了 4种培肥措施连续培肥 23年后农田土壤的CO2释放状况及其动力学特征。结果表明 ,含水量 12%至 24%范围内 ,土壤CO2释放过程完全可以用一级反应动力学方程 y =A0(1-e-kt)进行定量描述 (r2=0.9812～0.995 9,P 0.01) ;土壤CO2释放量和潜在可释放C量A0 随含水量增加呈线性增加 (r2=0.9728～0.9987,P0.01) ,速率常数k则随含水量增加呈线性降低 (r2=0.9356～0.9939,P0.01)。不同培肥措施明显影响土壤CO2释放状况及其动力学特征参数 ;NP化肥和厩肥 +NP化肥 2种培肥措施较不施肥对照明显增加了土壤CO2释放量、潜在可释放C量A0和速率常数k ;秸秆 +NP化肥培肥措施较不施肥对照显著增加了土壤CO2释放量、潜在可释放C量A0,但却显著降低了释放速率常数k ;有机无机肥料配合措施 (秸秆 +NP、厩肥 +NP)与单施NP化肥措施比较 ,明显降低了释放速率常数k。  相似文献   

18.
Summary Soil pH, total organic C, total N, exchangeable Al, available P, CO2 evolution, microbial biomass C and N, phosphatase and dehydrogenase activities were determined in acid soils sampled under spruce subjected to acid deposition, before and after liming. A slight decrease in pH values was observed from the edge of a tree canopy to the base of the trunk in acid soils. Liming drastically reduced exchangeable Al and increased CO2 evolution, microbial biomass, and the metabolic quotient. The microbial biomass C to total organic C ratio increased after liming but did not reach 2%, the average value considered valid in soils where the C content is in equilibrium, that is when C inputs are equal to C outputs. The microbial biomass C:N ratio decreased after liming, thus indicating that bacteria became predominant over fungi when soil acidity decreased. Dehydrogenase activity but not phosphatase activity was increased by liming. The decrease in phosphatase activity was not completely related to the increase in available P, but was also dependent on microbial growth and the decrease in acid phosphatase, the predominant component of acid soils.  相似文献   

19.
The comparative decomposition of tropical leaf litters (e.g. Andropogon gayanus, Casuarina equisetifolia, Faidherbia albida) of different qualities was investigated under laboratory conditions during a 60-day incubation period conducted with a typical oxisol. Total CO2-C, soil inorganic N, microbial biomass (fumigation-extraction), -glucosidase and dehydrogenase activities were determined over the incubation to assess how they responded to the addition of inorganic N (+N). Cumulative CO2-C evolved from the litter-amended soils was higher than that recorded for the unamended control soil. For the unfertilized treatment (0 N), correlation coefficients calculated between initial chemical data and CO2 flux during the first day of incubation were r =0.963 for water soluble-C and 0.869 for soluble carbohydrates (P <0.05). At the end of the incubation, the amounts of CO2-C in the F. albida- and A. gayanus-amended soils were higher than that in the C. equisetifolia-amended treatment. Cumulative net N immobilization increased during the first 30 days of incubation, the amounts being similar for A. gayanus- and C. equisetifolia-amended soil and higher than that recorded in the F. albida-amended treatment. Soil microbial biomass and enzyme activities increased in the litter-amended soils during the first 15 days of incubation and decreased (except for the dehydrogenase activity) thereafter. The addition of inorganic N modified the patterns of CO2-C respiration and net N immobilization. The magnitude of these modifications varied according to the litter quality. The use of an accurate indicator based on several litter components to predict the amplitude of organic material decomposition is discussed.  相似文献   

20.
武岩  红梅  林立龙  美丽  张建强 《土壤》2017,49(4):745-752
本研究以河套灌区农田盐化潮土为研究对象,通过静态暗箱-气相色谱法和田间土壤氨挥发原位测定法(通气法),研究了4种不同施肥措施(农民习惯施肥、膨润土+农民习惯施肥、生物炭+农民习惯施肥、腐殖酸+农民习惯施肥,分别标记为CK、B、C、HA)对土壤氨(NH_3)挥发及氧化亚氮(N_2O)排放的影响。结果表明:B处理可以显著降低土壤N_2O的排放,其N_2O累计排放量较CK降低30.9%,氮肥损失率较CK降低31.5%;其他处理N_2O累计排放量与CK无显著差异。各处理NH_3挥发速率于施肥灌水后3~5 d达到峰值,之后逐渐降低趋于平稳。B、C、HA处理可以显著降低土壤NH_3挥发,NH_3累计挥发量较CK降低56.0%、41.2%、49.0%,氮肥损失率较CK降低56.0%、41.2%、52.1%。相关性分析表明,土壤温度和空气温度与土壤N_2O的排放呈显著正相关;生育期土壤含水量处于151.2~203.3 g/kg,在这一范围内,土壤含水量与土壤N_2O的排放呈正相关关系。B处理可显著降低土壤NH3挥发及N_2O排放,且比CK增产11.1%,是较为合理的施肥措施。  相似文献   

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