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1.
中国农田土壤有机碳贮存的空间特征   总被引：2，自引：0，他引：2  
The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1546 typical cropland soil profiles, the paddy field and dryland SOC storage among quantified to characterize the spatial pattern of cropland SOC storage in China regions of China were systematically to examine the relationship between mean annual temperature, precipitation, soil texture features arid SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.  相似文献   

2.
Soil organic carbon(SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance(240–1 900 nm) and traditional physico-chemical methods.The representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg~(-1). Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.  相似文献   

3.
Changes in soil organic carbon (SOC) in agricultural soils influence soil quality and greenhouse gas concentrations in the atmosphere. Dry farmland covers more than 70% of the whole cropland area in China and plays an important role in mitigating carbon dioxide (CO2) emissions. In this study, 4109 dry farmland soil polygons were extracted using spatial overlay analysis of the soil layer (1:500000) and the land use layer (1:500000) to support Century model simulations of SOC dynamics for dry farmland in Anhui Province, East China from 1980 to 2008. Considering two field-validation sites, the Century model performed relatively well in modeling SOC dynamics for dry farmland in the province. The simulated results showed that the area-weighted mean soil organic carbon density (SOCD) of dry farmland increased from 18.77 Mg C ha1 in 1980 to 23.99 Mg C ha1 in 2008 with an average sequestration rate of 0.18 Mg C ha1 year?1. Approximately 94.9% of the total dry farmland area sequestered carbon while 5.1% had carbon lost. Over the past 29 years, the net SOC gain in dry farmland soils of the province was 19.37 Tg, with an average sequestration rate of 0.67 Tg C year1. Augmentation of SOC was primarily due to increased consumption of nitrogen fertilizer and farmyard manure. Moreover, SOC dynamics were highly differentiated among dry farmland soil groups. The integration of the Century model with a fine-scale soil database approach could be conveniently utilized as a tool for the accurate simulation of SOC dynamics at the regional scale.  相似文献   

4.
Opencast lignite mining in the Lusatia region of Germany has resulted in large scale landscape disturbances,which require suitable recultivation techniques in order to promote plant growth and establishment in the remaining nutrient-poor substrates with low water-holding capacity.Thus,the effects of two commercial soil additives (CSA),a hydrophilic polymer mixed with volcanic rock flour and bentonite (a-CSA),and digester solids from biogas plants enriched with humic acids and bentonite (b-CSA),on soil organic carbon (SOC) storage,plant yields and root biomass were assessed after cultivating perennial crops (Dactylis glomerata L.) in monoculture and Helianthus annuus L.-Brassica napus L.in crop rotation systems.The CSA were incorporated into the top 20 cm soil depth using a rotary spader.The results indicated that a-CSA led to a significant increase in plant yield during the first year,and improved root biomass in the following year.As a result,SOC stocks increased,especially in the 0-10 cm soil layer.No significant sequestration of additional SOC was observed on b-CSA-amended plots at the end of both years.Bulk density values decreased in all treatments under the monoculture system.It can be concluded that application of a-CSA enhanced soil water availability for plant uptake and consequently promoted plant growth and organic carbon sequestration.The relative enrichment of organic matter without effects on water-holding capacities of b-CSA treatments suggested that it was not suitable for rapid land reclamation.  相似文献   

5.
There is a limited knowledge of spatial heterogeneity in soil nutrients and soil respiration in the semi-arid and arid grasslands of China. This study investigated the spatial differences in soil nutrients and soil respiration among three desertified grasslands and within two shrub-dominated communities on the Ordos Plateau of Inner Mongolia, China in 2006. Both soil organic carbon (SOC) and total nitrogen (TN) were significantly different (P < 0.01) among the three desertified grasslands along a degradation gradient. Within the two shrub-dominated communities, the SOC and TN contents decreased with increasing distance from the main stems of the shrub, and this “fertile island” effect was most pronounced in the surface soil. The total soil respirations during the growing season were 131.26, 95.95, and 118.66 g C m-2, respectively, for the steppe, shrub, and shrub-perennial grass communities. The coefficient of variability of soil respiration was the highest in the shrub community and lowest in the steppe community. CO2 effluxes from the soil under the canopy of shrub were significantly higher than those from the soil covered with biological crusts and the bare soil in the interplant spaces in the shrub community. However, soil respiration beneath the shrubs was not different from that of the soil in the inter-shrub of the shrub-perennial grass community. This is probably due to the smaller shrub size. In the two shrub-dominated communities, spatial variability in soil respiration was found to depend on soil water content and C:N ratio.  相似文献   

6.
普通克里格法在土壤有机碳制图中的应用   总被引：1，自引：0，他引：1  
The quantification of the pattern and spatial distribution of soil organic carbon (SOC) is fundamental to understand many ecosystem processes.This study aimed to apply ordinary kriging (OK) to model the spatial distribution of SOC in a selected part of Zambia.A total of 100 soil samples were collected from the study area and analyzed for SOC by determining soil oxidizable carbon using the Walkley-Black method.An automated fitting procedure was followed when modeling the spatial structure of the SOC data with the exponential semivariogram.The results indicated that the short range spatial dependence of SOC was strong with a nugget close to zero.The spatial autocorrelation was high to medium with a nugget to sill ratio of 0.25.The root mean square error of the predictions was 0.64,which represented 58.18％ of the mean observed data for SOC.It can be concluded that the generated map could serve as a proxy for SOC in the region where evidence of spatial structure and quantitative estimates of uncertainty are reported.Therefore,the maps produced can be used as guides for various uses including optimization of soil sampling.  相似文献   

7.
Soil organic matter (SOM) content is one of the main factors to be considered in the evaluation of soil health and fertility. As timing, human and monetary resources often limit the amount of available data, geostatistical techniques provide a valid scientific approach to cope with spatial variability, to interpolate existing data and to predict values at unsampled locations for accurate SOM status survey. Using geostatistical and geographic information system (GIS) approaches, the spatial variability of some physical and chemical soil parameters was investigated under Mediterranean climatic condition in the Abruzzo region of central Italy, where soil erosion processes accelerated by human induced factors are the main causes of soil degradation associated with low SOM content. Experimental semivariograms were established to determine the spatial dependence of the soil variables under investigation. The results of 250 soil sampling point data were interpolated by means of ordinary kriging coupled with a GIS to produce contour maps distribution of soil texture, SOM content related to texture, and C/N ratio. The resulting spatial interpolation of the dataset highlighted a low content of SOM in relation with soil texture in most of the surveyed area (87%) and an optimal C/N ratio for only half of the investigated surface area. Spatial location of degraded area and the assessment of its magnitude can provide decision makers with an accurate support to design appropriate soil conservation strategies and then facilitate a regional planning of agri-environmental measures in the framework of the European Common Agricultural Policy.  相似文献   

8.
Carbon fractions in soils apparently vary not only in space, but also over time. A lack of knowledge on the seasonal variability of labile carbon fractions under arable land hampers the reliability and comparability of soil organic carbon(SOC) surveys from different studies. Therefore, we studied the seasonal variability of two SOC fractions, particulate organic matter(POM) and dissolved organic carbon(DOC), under maize cropping: POM was determined as the SOC content in particle-size fractions, and DOC was measured as the water-extractable SOC(WESOC) of air-dried soil. Ammonium, nitrate, and water-extractable nitrogen were measured as potential regulating factors of WESOC formation because carbon and nitrogen cycles in soils are strongly connected. There was a significant annual variation of WESOC(coefficient of variation(CV) = 30%). Temporal variations of SOC in particle-size fractions were smaller than those of WESOC. The stocks of SOC in particle-size fractions decreased with decreasing particle sizes, exhibiting a CV of 20%for the coarse sand-size fraction(250–2 000 μm), of 9% for the fine sand-size fraction(50–250 μm), and of 5% for the silt-size fraction(20–50 μm). The WESOC and SOC in particle-size fractions both peaked in March and reached the minimum in May/June and August, respectively. These results indicate the importance of the time of soil sampling during the course of a year, especially when investigating WESOC.  相似文献   

9.
A number of process-based models have been developed for quantifying carbon(C)sequestration in agro-ecosystems.The DeNitrification-DeComposition(DNDC)model was used to simulate and quantify long-term(1980-2008)soil organic carbon(SOC)dynamics in the important rice-producing province,Jiangsu,China.Changes in SOC storages were estimated from two soil databases differing in spatial resolution:a county database consisting of 68 polygons and a soil patch-based database of 701 polygons for all 3.7 Mha of rice fields in Jiangsu.The simulated SOC storage with the coarse resolution county database ranged between 131.0-320.6 Tg C in 1980 and 170.3-305.1 Tg C in 2008,respectively,while that estimated with the fine resolution database was 201.6 and 216.2 Tg C in 1980 and 2008,respectively.The results modeled with the soil databases differing in spatial resolution indicated that using the soil input data with higher resolution substantially increased the accuracy of the modeled results;and when lacking detailed soil datasets,the DNDC model,parameterized with the most sensitive factor(MSF) method to cope with attribute uncertainty,could still produce acceptable results although with deviations of up to 60% for the case study reported in this paper.  相似文献   

10.
地中海山地土壤中团聚体的形成和有机质的储存   总被引：1，自引：0，他引：1  
R. M. POCH  M. ANT&#;NEZ 《土壤圈》2010,20(6):702-710
Soil aggregation and organic matter of soils from the pre-Pyrenean range in Catalonia (NE Spain) were studied, in order to assess their quality as carbon sinks and also to select the best soil management practices to preserve their quality. Aggregate stability, organic carbon and micromorphology were investigated. The highest amount of organic carbon was found in alluvial, deep soils (228 Mg C ha-1), and the lowest was in a shallow, stony soil with a low plant cover (78 Mg C ha-1). Subsurface horizons of degraded soils under pastures were the ones with smaller and less-stable aggregates. Fresh residues of organic matter (OM) were found mostly in interaggregate spaces. Within the aggregates there were some organic remains that were beginning to decompose, and also impregnative nodules of amorphous OM. Although OM was evenly distributed among the aggregate fractions, the larger blocky peds had more specific surface, contained less decomposed OM and had a lower organic/mineral interphase than smaller crumb aggregates, which were also more stable. Soil carbon storage was affected primarily by the OM inputs in the surface horizons. In order to store organic carbon over the mid-and long-term periods, the mechanisms favouring structuration through biological activity and creating small aggregates with intrapedal stable microporosities seemed to be the most effective.  相似文献   

11.
氮素形态对樱桃番茄果实氮素和有机酸代谢的影响   总被引：1，自引：0，他引：1  
Cherry tomatoes(Lycopersicon esculentum Mill.,cv.hongyangli) were hydroponically cultivated in a greenhouse to determine the effect of different nitrogen(N) forms on organic acid concentration and the activities of related enzymes involved in nitrogen and organic acid metabolism during cherry tomato fruit development.The results showed that fruit nitrate reductase(NR) activity was much higher following treatment with 100% NO 3 and 75% NO 3 + 25% NH + 4 than with 100% NH + 4 except at maturity.Glutamine synthetase(GS) activity trended downward during fruit development under all three treatments.Plants fed 100% NH + 4 had the lowest fruit citrate and malate levels at maturity,with the highest malate concentration at an early stage.The activity of phosphoenolpyruvate carboxylase(PEPC) was found to be in accord with the malate concentration with every N source.Under all three N forms,the citrate synthase(CS) activity peaked one week before the citrate concentration.  相似文献   

12.
研究了全硝（100%NO-3）、铵硝配施（75%NO-3: 25%NH+4）及全铵（100%NH+4）营养对樱桃番茄果实有机酸含量的影响,测定了与有机酸合成相关的磷酸烯醇式丙酮酸羧化酶（PEPC）、柠檬酸合成酶（CS）、苹果酸脱氢酶（MDH）活性变化,并利用RT-PCR检测了相应的基因在转录水平上的表达差异。结果表明, 1）全硝和铵硝配施处理下果实柠檬酸含量在整个生育期均显著高于全铵处理,而铵硝配施处理下果实中柠檬酸和苹果酸含量在成熟期均显著低于全硝处理。2）不同形态氮素及配施处理下,果实中柠檬酸含量与CS活性的变化趋势均呈单峰型,但到达峰值的时间不同。全铵处理下果实苹果酸含量与PEPC活性呈显著正相关,全硝、铵硝配施处理下果实苹果酸和柠檬酸含量都与MDH活性呈显著正相关。3）在膨大期和成熟期,全硝处理和铵硝配施处理下PEPC基因（PPC1、PPC2）表达显著高于全铵处理; 线粒体苹果酸脱氢酶（mMDH）的表达对果实苹果酸脱氢酶活性和苹果酸积累起主要作用,表明适当比例的铵硝配施可能通过影响果实中PEPC和MDH的活性和基因表达从而显著降低成熟果实有机酸的含量。  相似文献   

13.
增铵营养对番茄幼苗生长和有机酸含量的影响   总被引：9，自引：0，他引：9  
A hydroponic experiment was conducted to study the effect of partial replacement of NO(3^-)-N by NH -N on theseedling growth and organic acid content of tomato (Lycopersicon esculentum Mill.). A completely randomized designwas established with three replications and five treatments, i.e., NO(3^-)-N/NH(4^ )-N of 100/0, 75/25, 50/50, 25/75 and0/100. Results showed that 25% replacement of NO(3^-)-N by NH(4^ )-N significantly (P = 0.05) improved fresh and dryweight, revealing that a proper percentage of NH -N was important for tomato nitrogen nutrition. This could increasethe plant growth even though tomato was a crop that preferred nitrate nutrition. Also an increase in the proportion ofNH -N in the nutrient solution led to a significant decrease (P=0.05) in malate, citrate and fumarate. However, the25% NH(4^ )-N plus 75% NO(3^-)-N treatment had no significant effect (P = 0.05) on the 2-ketoglutarate, succinate or oxalicacid content, showing that only some organic acids in tomato plants were affected. Only pyruvate increased significantly(P=0.05), and it only increased for 25% and 50% replacement of NO(3^-)-N by NH(4^ )-N. Metabolism of these organicacids, especially malate, citrate and fumarate, should be further studied at the molecular level in vegetables applied withdifferent nitrogen forms.  相似文献   

14.
【目的】探明不同保护性耕作措施对黄土高原旱作土壤不同粒级复合体中有机氮含量与分配的影响,可对评价耕作措施的效果提供科学依据。【方法】基于黄土高原旱区14年的长期定位试验,采用Bremner法, 对传统耕作(T)、免耕(NT)、秸秆覆盖(TS)及免耕+秸秆覆盖(NTS)四种耕作措施条件下不同土壤粒级复合体中的有机氮含量和分配进行了研究。【结果】保护性耕作方式均增加了2~10 μm粒级土壤复合体的比例,增幅为20.0%~31.7%;降低了0~2 μm粒级土壤复合体在土壤中所占的比例,降幅为27.6%~31.0%。在所有耕作措施下,耕层土壤中不同粒级复合体所占的比例为10~50 μm＞2~10 μm＞0~2 μm＞50~100 μm＞100 μm。保护性耕作方式均明显提高了耕层0~2 μm粒级土壤复合体中氨基糖氮的含量,增幅在46.9%~107.1%,降低了单位质量0~2 μm粒级土壤复合体中的NH+4-N含量,降幅在14.8%~27.0%;明显提高了耕层单位质量2~10 μm粒级土壤复合体中酸解总氮、氨基酸氮和氨基糖氮的含量,增幅分别为8.2%~14.3%、16.2%~31.5%和154.9%~184.3%;降低了单位质量2~10 μm粒级土壤复合体中NH+ 4-N的含量,降幅为28.7%~46.6%。传统耕作(T)条件下,与各粒级土壤复合体相结合的有机氮量顺序为10~50 μm＞0~2 μm＞2~10 μm＞50~100 μm＞100 μm以上,而保护性耕作条件下,与各粒级土壤复合体相结合的有机氮量顺序为10~50 μm＞2~10 μm＞0~2 μm＞50~100 μm＞100 μm以上;与传统耕作相比,保护性耕作措施显著地增加了耕层土壤中酸解总氮、氨基酸氮、氨基糖氮的含量,增幅分别为6.6%~20.4%、89.0%~113.0%和11.9%~31.6%,降低了NH+4-N的含量。【结论】与传统耕作(T)处理相比,保护性耕作(NT、TS、NTS)措施明显提高了土壤2~10 μm粒级复合体的比例,降低了0~2 μm粒级复合体的比例;增加了耕层土壤中酸解氮总氮、氨基糖态氮和氨基酸态氮的含量,降低了NH+ 4-N的含量。土壤中以氨基酸态氮占优势地位,其它形态的有机氮无明显分布规律。  相似文献   

15.
增铵营养对番茄植株伤流液组分及含量的影响   总被引：1，自引：1，他引：0  
在总氮(N)浓度相等的条件下,研究全硝营养(100% NO3-)和25% 增铵营养(NH4+∶NO3- = 25%∶75%)对开花期和幼果期番茄植株伤流液各组分含量的影响.结果表明,增铵营养显著增加幼果期伤流液中 K的含量,对Ca、Mg、P元素含量没有显著影响;增铵营养下伤流液中 NO3- 的含量下降、NH4+ 含量增加,氨基酸、苹果酸等的含量均显著增加,氨基酸/硝态氮含量之比显著提高,表明喜硝作物适当增铵不仅能够提高根系活力,显著促进K的吸收以供果实发育之需,而且提高了植株整体同化N素的能力.  相似文献   

16.
不同有机肥对采煤塌陷区土壤氮素矿化动态特征研究   总被引：1，自引：1，他引：0  
为揭示不同有机肥对煤矿复垦土壤氮素矿化特性的影响,以山西省孝义市水峪煤矿采煤塌陷复垦土壤为研究对象,采用室内好气培养法,研究在40%含水量和30℃培养条件下,施用3种有机肥(鸡粪、猪粪、牛粪)后在0~161天的氮素矿化动态特征,以明确不同有机肥对该矿区复垦土壤氮素矿化特征,从而预估不同有机肥的供氮特性,为合理施用有机肥进行低产农田的培肥改造提供科学依据。结果表明:(1)各处理0~14天铵态氮含量均随培养时间的延长迅速下降,与培养时间呈极显著负相关关系(P<0.01),14~161天土壤铵态氮含量维持在较低水平,培养结束时,各处理铵态氮含量均低于1.31mg/kg。(2)各处理土壤硝态氮含量、累积量及矿质氮累积量变化均呈近似的“S”形曲线递增,表现为0~56天缓慢增加,56~84天迅速增加,84天至培养结束(161天)其含量基本不变。培养结束时不同处理间硝态氮含量、累积量及矿质氮累积量整体上均表现为鸡粪>猪粪>牛粪>空白,且鸡粪较猪粪和牛粪处理间存在显著差异,猪粪和牛粪较空白处理间存在显著差异(P<0.05)。(3)不同施肥处理出现氮素净矿化的时间点不同,其中鸡粪处理在第14天时最早出现净矿化现象,而猪粪和牛粪在培养28天后才出现明显的氮素净矿化。(4)不同施肥处理在培养的不同阶段硝态氮和矿质氮累积速率不同,但整体趋势一致,表现为培养0~84天各处理土壤累积矿化波动较大,56~84天达到峰值,培养84~161天各处理矿化速率平稳下降。总体来看,有机肥的施入能有效促进煤矿复垦土壤氮素矿化,从而提高土壤氮素有效性。其中,施鸡粪较猪粪和牛粪对提高矿区复垦土壤有效氮效果更好。4种处理的氮素矿化效果总体表现为鸡粪>猪粪>牛粪>空白。  相似文献   

17.
Two experiments were conducted to determine the effects of various NH4(+)-N/NO3(-)-N percentages on growth and mineral concentrations in potato (Solanum tuberosum L.) plants using a non-recirculating nutrient film system in a controlled environment. The first experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 20/80, 40/60, 60/40, 80/20, and 100/0 with the same total N concentration of 4 mM. The second experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 4/96, 8/92, 12/88, 16/84, and 20/80 again with the same total N of 4 mM. In each experiment, plants were harvested 35 days after transplanting when tubers had been initiated and started to enlarge. Dry weights of shoots, tubers, and whole plant at the harvest were increased significantly with all mixed nitrogen treatments as compared with single NH4+ or NO3- form. The enhanced growth with mixed nitrogen was greatest at 8% to 20% NH4(+)-N. Also, the concentrations and accumulation of total N in the shoots and roots were greater with mixed nitrogen than with separate NH4+ or NO3- nutrition. With NH4+ present in the solutions, the concentrations of P and Cl in the shoots were increased compared to NO3- alone, whereas the tissue concentrations of Ca and Mg were decreased. It was concluded that nitrogen fertilization provided with combined NH4+ and NO3- forms, even at small proportions of NH4+, can enhance nitrogen uptake and productivity in potato plants.  相似文献   

18.
The effect of three different nitrogen (N) supply forms differing in their ammonium-to-nitrate (NH(4):NO(3)) ratio (100% NH(4), 50% NH(4) + 50% NO(3), 100% NO(3)) under three different levels of daily photosynthetic active radiation (PAR) (low, 5.0; medium, 6.8; high, 9.0 mol m(-2) day(-1)) on a range of desirable health-promoting phytochemicals in Brassica rapa subsp. nipposinica var. chinoleifera and Brassica juncea was determined. The 100% NH(4) supply under medium PAR levels led to the highest concentration of glucosinolates based on a low nitrogen/sulfur ratio as well as high levels of carotenoids in the leaves of both Brassica species. However, the 100% NH(4) supply under low and medium PAR levels resulted in low concentrations of flavonoids based on high N concentration in the leaves. Thus, the data provided here have strong implications for crop management strategies aimed at optimizing both the concentration and composition of a range of phytochemicals.  相似文献   

19.
热带亚热带酸性土壤硝化作用与氮淋溶特征   总被引：3，自引：0，他引：3  
通过室内好气培养和土柱模拟淋洗培养试验,研究了氨基氮肥加入对热带亚热带4种不同性质和利用方式酸性土壤硝化、氮及盐基离子淋溶、土壤及淋出液酸化的影响。4种土壤分别为采自花岗岩发育的海南林地砖红壤(HR)、玄武岩发育的云南林地砖红壤(YR)、第四纪红黏土发育的江西旱地红壤(RU)和第四纪下蜀黄土发育的江苏旱地黄棕壤(YU)。结果表明:4种土壤硝化作用大小表现为YURUYRHR。HR主要以可溶性有机氮(DON)和NH_4~+-N形态淋失,YU土壤的氮淋溶形态以NO_3~–-N为主,YR和RU土壤的氮淋溶形态NO_3~–-N、NH_4~+-N和DON兼而有之。盐基离子总淋失量与NO_3~–-N淋失量显著正相关,但各盐基离子淋失由于离子本性和土壤性质差异并不完全一致。Ca~(2+)在缓冲外源NH_4~+-N硝化致酸和平衡NO_3~–-N淋失所带负电荷过程中起重要作用。在阳离子交换量小、盐基饱和度低的土壤(如RU土壤),外源NH_4~+-N的硝化和淋失不仅导致盐基离子淋失,而且引发NH_4~+-N、甚至是H~+淋失。综上,热带亚热带地区土壤上外源氮输入的增加可能会在更短的时间内导致氮素向系统外的流失,引发环境问题。  相似文献   

20.
镇江市古运河河岸沉积物氮及有机质分布特征   总被引：1，自引：0，他引：1  
为揭示镇江市古运河河岸带表层沉积物中氮元素含量的分布特征,结合古运河周边环境状况,选择6个典型的采样点对其表层沉积物进行样品采集,对各样品沉积物总氮（TN）,氨氮（NH4+-N）,硝氮（NO3--N）,亚硝氮（NO2--N）以及有机质（O.M）和pH值进行了分析,并根据经验公式对沉积物有机氮进行了计算。结果表明,TN,NH4+-N,NO3--N,NO2--N以及Org-N含量介于0.39~2.40 g/kg,1.63~11.31 mg/kg,2.46~6.95 mg/kg,0.54~2.29 mg/kg,0.99~2.32 g/kg,总氮和有机氮的变异系数最大,为83.59%,氨态氮、硝态氮以及亚硝态氮的变异系数介于40.36%~49.15%,表现为中等离散程度,表明研究区域总氮和有机氮的离散程度较高,其在空间分布上呈现较为明显的异质性;古运河沉积物有机质含量介于0.99%~2.32%,变异系数为32.50%,表现为中等变异性,表明各采样点的沉积物有机质含量变化幅度中等;通过沉积物C/N值来判断,古运河有机质主要以陆源贡献为主;相关性分析结果表明,NO2--N与TN的关系最为密切,而氨氮与硝氮、亚硝氮以及有机氮之间的相关性不强,说明氨氮与其他形态氮在沉积物方式上存在一定的差异性。此外,pH值对古运河表层沉积物氮形态的具有较为显著的影响。  相似文献   

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