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1.
Background Aim and Scope
Soil monitoring in Germany should register the current soil condition, monitor its changes and provide a forecast for future development. In order to achieve these goals, the long-term soil monitoring sites in Germany (BDF -Bodendauerbeobachtungsflächen) have been established by the federal states. This has been done according to criteria worked out by soil monitoring experts. In this article a method for the examination of the suitability of Germany’s soil monitoring sites for soil conservation and protection purposes, as well as for environmental monitoring and reporting, is introduced. This method includes the landscape representativity of soil monitoring sites as well as the comparability and spatial validity of collected data.Methods
BDF-criteria are operationalized in a three-step procedure: At first, a metadatabase is established containing information that allows the comparison of monitoring sites by means of measuring parameters, methods and quality assurance as well as quality control of measurements. Secondly, the representativity of the BDF-sites for soil types, land use, vegetation, and climate (air temperature, duration of sunlight, precipitation) by means of frequency statistics and neighborhood analysis is quantified. At last, the spatial validity of soil monitoring data is examined through the application of geostatistical methods. Both data and statistical methods are integrated in a Geoinformationsystem (GIS).Results
The analysis of metadata reveals that the soil monitoring is of great importance for environmental analysis because of its ecosystematic concept and its considerable degree of methodical harmonization. Assuming that the number of BDF should be directly proportional to the areal portion of an ecoregion in the entire area of Germany, it can be shown that the geographical distribution of BDF-sites fit quite well according to the areal portions of the ecoregions. The maximum deviation is about ñ 6%. If the number of BDF is not proportional to the area covered by a certain combination of site characteristics, these areas can either be complemented or thinned through MNR-indices derived by neighborhood analysis. Soil monitoring sites can be added where the MNR are highest and removed where MNR are lowest. Throughout the neighborhood analysis, three GISmaps were processed: ecoregionaiization, soil types and land use. Decisions to reduce the spatial density of monitoring sites should not only be based on the landscape representativness of monitoring networks, but on the support of geostatistical analysis of measured data as well. For example, the results of the geostatistical analysis of Pb-concentrations in top soils are compared for a complete and a reduced BDF monitoring network.Conclusion
The investigations show that not only the proportional distribution of monitoring sites in landscape units (landscape representativity) is important for the assessment of environmental monitoring networks; The number of monitoring sites, rather, should be sufficient to guarantee a spatial representation of the respective measurement variable. Their geographical distribution should be based on the spatial model of landscape units. Additionally, particular criteria that are important for the object of investigation, for example the distance to emitters, should also be considered.Perspective
It is strongly recommended that activities for the integration of ecological data collected in diverse monitoring networks be intensified. A central German environmental information system should be established in order to realize integrated analysis of environmental data by aspects of harmonization and representativity. Furthermore, Internet and GIS technologies should be used to assist the environmental data acquisition in Germany. A prototype of such an instrument, the socalled Internet and GIS-based Environmental Monitoring System (IGUS) was already established and tested in the moss monitoring program 2000.2.
Chao Ye Zhonglu Guo Chongfa Cai Junguang Wang Jia Deng 《Journal of Soils and Sediments》2017,17(1):210-219
Purpose
Soil aggregate mechanical characteristics can significantly affect soil strength and are important soil properties to predict soil erodibility. However, in most research, the aggregate mechanical strength is always measured under air-dried condition, and limited information is available about the mechanical strength of aggregates and soil blocks with different water contents. This study evaluated the effects of water content, bulk density, and aggregate size on mechanical properties of soil blocks and aggregates.Materials and methods
Shear strength (τ) parameters (φ and c) of soil blocks in different states (undisturbed and remoulded) and tensile strength (TS) of aggregates were determined in the laboratory on two soils derived from Quaternary red clay (Q) and shale (S) with variations in water content, bulk density, and aggregate size.Results and discussion
The results indicated that the φ values were higher in drier and denser soil and showed no obvious variation with varying aggregate size. The c values increased first and then decreased with increasing water content and decreasing aggregate size and increased with increasing bulk density. The water content corresponding to the rapid decrease of the c value appeared to be related to soil properties. Tensile strength increased with decreasing water content in all sizes of aggregates. It decreased with increasing aggregate size at a relative low water content (3.2–7.3 %), but increased with increasing aggregate size at a relative high water content (10.6–14.8 %). The effect of soil moisture on soil strength varied with soil states. Thus, water content, bulk density, and aggregate size have significant effects on the mechanical properties of the soil blocks and aggregates.Conclusions
The result from this research may contribute to a better understanding of the soil erosion resistance of Aquults from the perspective of soil mechanics.3.
Several recent studies have observed physical, chemical and microbiological heterogeneities on the scale of soil aggregates. The publications emphasize the ecological importance of these small scale gradients. This paper introduces a method for the rapid fractionation of soil structure units into a surface fraction and a core fraction. The technique combines a rapid freezing in liquid N2 and standardized wet sieving of the structure units. During the sieving process the aggregate surfaces begin to thaw and are consequently washed through the sieve. The soil passing the sieve during a specified time is termed aggregate surface fraction, the remainder is the aggregate core fraction. Samples from 18 forest soil profiles were taken to study the precision and accuracy of the method, as well as factors determining the efficiency of fractionation. The precision of aggregate fractionation as determined by parallel fractionations yielded coefficients of variability of 5.3 to 7.5% and 6.5 to 11.4% for the amount of core and surface fraction, respectively. Furthermore, the proposed technique yielded results comparable to those obtained by manual razor-peeling of the aggregate surfaces. The variation of concentrations of chemical parameters in water extracts of both aggregate fractions was up to six times greater than in soil solutions obtained from mixed samples. Increasing soil organic C resulted in a decrease in the proportion of the aggregate surface soil collected under fixed sieving conditions, while clay content correlated positively with the amount of the aggregate surface fraction collected. 相似文献
4.
Aki Sinkkonen Sari Kauppi Veera Pukkila Hui Nan Tomasz Płociniczak Merja Kontro Rauni Strömmer Martin Romantschuk 《Journal of Soils and Sediments》2013,13(8):1430-1438
Purpose
Previous investigations—field samplings and laboratory experiments—support the hypothesis that the degradation of s-triazines is enhanced in previously exposed as compared to pristine soils in terrestrial environments. Despite this, bottlenecks of soil sampling and various soil modification practices in microcosm studies have made it difficult to guarantee that previous contamination history enhances contaminant degradation regardless of soil origin in terrestrial ecosystems. We test the hypothesis that the degradation of simazine (2-chloro-4,6-bis(ethylamino)-s-triazine) is enhanced in previously exposed soils as compared to pristine soils in 10 l buckets at the mesocosm scale.Materials and methods
We collected soil at three separate sites consisting of a previously exposed and a pristine field. At every field, soil was collected at three separate plots and simazine degradation (days 0 and 65) and the response to atzB degrader gene primers (days 0 and 110) were followed. We analyzed the results using analysis of covariance (ANCOVA). Previous exposure and field site were assessed as fixed factors and initial simazine concentration and abiotic soil conditions as covariates.Results and discussion
After the 65-day exposure, remaining simazine concentrations depended on previous exposure but not on collection site. The response to atzB gene primers was positive in all mesocosms where simazine degradation had been rapid. Soil moisture, pH, and organic matter content were insignificant. If soil moisture was not included in the ANCOVA model, previous exposure did not appear as a significant factor.Conclusions
The results support the hypothesis that simazine is degraded more rapidly in previously exposed soils as compared to pristine environments, provided that degradation genes are available. Previously exposed soil might be used to enhance the degradation of simazine in recently contaminated terrestrial soils, supposing that the central requirements for microbial growth are adequate. 相似文献5.
Fingerprinting sediment sources in the outlet reservoir of a hilly cultivated catchment in Tunisia 总被引：1，自引：1，他引：1
Abir Ben Slimane Damien Raclot Olivier Evrard Mustapha Sanaa Irène Lefèvre Mehdi Ahmadi Mouna Tounsi Cornelia Rumpel Abdallah Ben Mammou Yves Le Bissonnais 《Journal of Soils and Sediments》2013,13(4):801-815
Purpose
Approximately 74 % of agricultural soils in Tunisia are affected by water erosion, leading to the siltation of numerous human-made reservoirs and therefore a loss of water storage capacity. The objective of this study was to propose a methodology for estimating the relative contributions of gully/channel bank erosion and surface topsoil erosion to the sediment accumulated in small reservoirs.Materials and methods
We tested an approach based on the sediment fingerprinting technique for sediments collected from a reservoir (which has been in operation since 1994) at the outlet of a catchment (Kamech, 2.63 km2). Sampling concentrated on the soil surface (in both cropland and grassland), gullies and channel banks. A total of 17 sediment cores were collected along a longitudinal transect of the Kamech reservoir to investigate the origin of the sediment throughout the reservoir. Radionuclides (particularly caesium-137, 137Cs) and nutrients (total phosphorus, total nitrogen and total organic carbon (TOC)) were analysed as potential tracers.Results and discussion
The applications of a mixing model with 137Cs alone or 137Cs and TOC provided very similar results: The dominant source of sediment was surface erosion, which was responsible for 80 % of the total erosion within the Kamech catchment. Additionally, we showed that the analysis of a single composite core provided information on the sediment origin that was consistent with the analysis of all sediment layers in the core. We demonstrated the importance of the core sampling location within the reservoir for obtaining reliable information regarding sediment sources and the dominant erosion processes.Conclusions
The dominance of surface erosion processes indicates that conservation farming practices are required to mitigate erosion in the agricultural Kamech catchment. Based on the results from 17 sediment cores, guidelines regarding the number and location of sampling cores to be collected for sediment fingerprinting are proposed. We showed that the collection of two cores limited the sediment source apportionment uncertainty due to the core sampling scheme to <10 %. 相似文献6.
The selenium and salt content of the top 15 cm of the soil profile at Kesterson Reservoir (Merced County, California) have been monitored annually to develop a data set that provides a foundation for: (1) evaluating the status of the selenium inventory and biological hazards at Kesterson Reservoir; (2) understanding selenium fluxes near the soil surface; and (3) making long-term predictions of the selenium concentrations available for plant uptake and dissolution into rainwater ephemeral pools. Results of this monitoring program indicate that the soil selenium inventory at Kesterson may be categorized in terms of three main patterns: (1) spatial trends associated with historic Reservoir operations; (2) temporal trends due to the oxidation and remobilization of the selenium inventory and; (3) temporal trends due to seasonal cycles. It is evident that the selenium inventory and distribution within the soil profile will evolve slowly whereby the fraction of the total inventory that is now immobile (est. at 93%) will oxidize to more mobile and bioavailable forms. Two major issues with broad importance were raised concerning sampling the surface soil selenium environment at Kesterson which may be helpful to others conducting investigations of similar nature. These issues include: (1) the recognition that variations in surface soil contaminant concentrations due to seasonal redistribution may obscure long term trends and; (2) large spatial variability in soil contaminant concentrations make it difficult to obtain large enough data sets to detect statistically significant changes in the contaminant inventory until large changes have already taken place. A combination of both process-oriented and synoptic type sampling are recommended to better define time trends. 相似文献
7.
Zhijie Chen Heikki Setälä Shicong Geng Shijie Han Shuqi Wang Guanhua Dai Junhui Zhang 《Journal of Soils and Sediments》2017,17(1):23-34
Purpose
Anthropogenic-induced greenhouse gas (GHG) emission rates derived from the soil are influenced by long-term nitrogen (N) deposition and N fertilization. However, our understanding of the interplay between increased N load and GHG emissions among soil aggregates is incomplete.Materials and methods
Here, we conducted an incubation experiment to explore the effects of soil aggregate size and N addition on GHG emissions. The soil aggregate samples (0–10 cm) were collected from two 6-year N addition experiment sites with different vegetation types (mixed Korean pine forest vs. broad-leaved forest) in Northeast China. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) production were quantified from the soil samples in the laboratory using gas chromatography with 24-h intervals during the incubation (at 20 °C for 168 h with 80 % field water capacity).Results and discussion
The results showed that the GHG emission/uptake rates were significantly higher in the micro-aggregates than in the macro-aggregates due to the higher concentration of soil bio-chemical properties (DOC, MBC, NO3 ?, NH4 +, SOC and TN) in smaller aggregates. For the N addition treatments, the emission/uptake rates of GHG decreased after N addition across aggregate sizes especially in mixed Korean pine forest where CO2 emission was decreased about 30 %. Similar patterns in GHG emission/uptake rates expressed by per soil organic matter basis were observed in response to N addition treatments, indicating that N addition might decrease the decomposability of SOM in mixed Korean pine forest. The global warming potential (GWP) which was mainly contributed by CO2 emission (>98 %) decreased in mixed Korean pine forest after N addition but no changes in broad-leaved forest.Conclusions
These findings suggest that soil aggregate size is an important factor controlling GHG emissions through mediating the content of substrate resources in temperate forest ecosystems. The inhibitory effect of N addition on the GHG emission/uptake rates depends on the forest type.8.
S. J. Fansler J. L. Smith H. Bolton Jr V. L. Bailey 《Biology and Fertility of Soils》2005,42(1):17-23
Knowledge of the cycling and compartmentalization of soil C that influence C storage may lead to the development of strategies to increase soil C storage potentials. The objective of this study was to use soil hydrolases and soil aggregate fractionation to explore the relationship between C cycling activity and soil aggregate structure. The prairie chronosequence soils were native prairie (NP) and agricultural (AG) and tallgrass prairies restored from agriculture in 1979 (RP-79) and 1993 (RP-93). Assays for -glucosidase (E.C. 3.2.1.21) and N-acetyl--glucosaminidase (NAGase, EC 3.2.1.30) activities were conducted on four aggregate size fractions (>2 mm, 1–2 mm, 250 m–1 mm, and 2–250 m) from each soil. There were significantly greater amounts of >2-mm aggregates in the RP-79 and RP-93 soils compared to the NP and AG soils due to rapid C accumulation from native plant establishment. Activities for both enzymes (g PNP g–1 soil h–1) were greatest in the microaggregate (2–250 m) compared to the macroaggregate (>2 mm) fraction; however, microaggregates are a small proportion of each soil (<12%) compared to the macroaggregates (75%). The RP soils have a hierarchical aggregate system with most of the enzyme activity in the largest aggregate fractions. The NP and AG soils show no hierarchical structure based on aggregate C accretion and significant C enzyme activity in smaller aggregates. The distribution of enzyme activity may play a role in the storage of C whereby the aggrading restored soils may be more susceptible to C loss during turnover of macroaggregates compared to the AG and NP soils with less macroaggregates. 相似文献
9.
Soil plots were established in catchments within the frame of the Norwegian Monitoring Programme for Long-Range Transported Air Pollutants. Four soil plots of about 10 m by 20 m were established within each catchment in areas with relatively homogeneous soil and vegetation. Multiple soil cores were taken at 50 points in a grid from each plot (repeated 4 times) and the samples were pooled by depths. Each soil core was divided by soil horizon, by predefined depths or by a combination of these, usually giving one soil sample for each 2-cm-depth down to about 15 cm. The soil pH measured in water suspension varied for all soils between 3.5 and 4.9. Base saturation measured at pH 7 varied between 2% and 22% with the highest values in the upper, more humus rich layers. All of the monitored catchments include acid soils poor in base cations. After 8 years the plots were resampled using the same procedure as for the first sampling. In most of the plots a decreasing pH trend from the first to the second sampling was measured. However, the base saturation was generally higher in all plots at the second sampling compared with the first. There are no clear effects of the different pollution regimes in the various catchments. It must be emphasized, however, that 8 years is a short period for measuring long-term soil changes. 相似文献
10.
Svetlana N. Sushkova Tatiana M. Minkina Saglara S. Mandzhieva Galina K. Vasilyeva Nikolay I. Borisenko Irina G. Turina Olga V. Bolotova Tatiana V. Varduni Rıdvan Kızılkaya 《Journal of Soils and Sediments》2016,16(4):1323-1329
Purpose
The optimization of benzo[a]pyrene extraction conditions by subcritical water extraction method from soils is the purpose of the research. The optimal conditions for benzo[a]pyrene recovery are 30-min extraction by water in a special steel cartridge at 250 °C and 100 atm.Materials and methods
Studies were conducted on the soils of monitoring plots subjected to Novocherkassk Power Station emissions. Monitoring plots were established at different distances from the Novocherkassk Power Station (NPS; 1.0–20.0 km).Results and discussion
It was shown that the use of water in subcritical state as a solvent for benzo[a]pyrene extraction from soil allows to avoid large volumes of organic solvents and to decrease the time of sample preparation. It is shown that the maximum benzo[a]pyrene maintenance was observed in soils of the monitoring plots located most close (to 5 km) to a pollution source in the area of the prevailing direction of a wind rose. Dynamics of pollutant accumulation in soils depend on number of Novocherkassk state district power station emissions.Conclusions
The method of benzo[a]pyrene subcritical water extraction from soil was developed and approbated during long-term monitoring researches of technogenic polluted territories. The optimum conditions for benzo[a]pyrene extraction from soil have been determined: the soil is treating by subcritical water at 250 °C and 100 atm of pressure for 30 min. Trends in the accumulation of benzo[a]pyrene in soil zones of the thermal power plant influence have been researched over a 5-year period of monitoring observations by subcritical water extraction method. Benzo[a]pyrene accumulation in soils depends on the technogenic emissions to the atmosphere from Novocherkassk power station and on the soil physical and chemical properties.11.
Song Li Yue Li Xueru Huang Feinan Hu Xinmin Liu Hang Li 《Journal of Soils and Sediments》2018,18(3):863-873
Purpose
The extensive application of phosphate fertilizers could produce a series of environmental problems by adsorbing on the surface of soil particle and migrating into water during soil erosion. Therefore, this study is to explore the effects of phosphate on soil aggregate stability and soil erosion and to analyze the mechanisms of phosphate enhancing soil erosion from the scope of soil charge density, electric field, and particle interaction.Materials and methods
A variable charged soil (0–20 cm) was pre-treated firstly by KCl, K2HPO4, and KH2PO4, respectively. Under the conditions of KCl, K2HPO4, and KH2PO4 solutions with concentrations of 0.0001, 0.001, 0.01, 0.1, and 1 mol L?1, (1) the amounts of soil particle transport and erosion intensities were measured using rainfall simulation with electrolyte solutions instead of rainwater; (2) the aggregate stabilities were measured by weighing the particles and micro-aggregates of <2, 5, and 10 μm after soil aggregate breakdown in electrolyte solutions; and (3) the zeta potentials of soil particles were measured in electrolyte solutions.Results and discussion
The application of K2HPO4 and KH2PO4 in soil strongly enhanced soil aggregate breakdown and soil erosion, while in KCl application, soil aggregates were stable and erosion did not occur. Moreover, the intensities of soil aggregate breakdown and soil erosion for K2HPO4 application were much stronger than that for KH2PO4 application. Phosphate, especially K2HPO4, strongly increased surface negative charge density of soil particles and thus increased the electrostatic repulsive pressure between adjacent soil particles in aggregates, and as a result, the soil erosion intensity increased. However, the surface charge density was not increased by the increased pH, specific adsorption, and dispersion force adsorption but possibly attributed to a non-classic induction force adsorption arising from the anionic non-classic polarization in the strong electric field around soil particle surface.Conclusions
The application of phosphate decreased aggregate stability and stimulated soil erosion through increasing charge density of particle surface by a new non-classic induction adsorption of phosphate.12.
《Communications in Soil Science and Plant Analysis》2012,43(18):2263-2277
ABSTRACTHow to address improving degraded soil has become an increased concern for agricultural production. Biomass ash is used for remediation of degraded soil and improvement in soil structure. To investigate the responses of aggregate stability and soil consistency by biomass ash and other amendments, a pot experiment with a degraded soil and seven treatments including a control (CK), no fertilizer or amendment; only N-P-K fertilizer (F); N-P-K fertilizer with lime (FL), lime and zeolite (FLZ), biomass ash (FBA), biological fertilizer (FBF) and peat ash (FPA), respectively, were conducted. Stability of soil aggregate, water-holding capacity, and soil consistency was analyzed within a lettuce-water spinach-lettuce planting system. Results showed that amendment additions significantly raised the fractions of >0.25 mm soil aggregate. Applications of biomass ash reduced the percentage of aggregate destruction (PAD) by 45.07%-59.97% and reduced the value of fractal dimension (D) by 1.79–2.16 during whole cultivation period, indicating the stability of soil aggregates. Soil organic matter (SOM) plays a key role in soil consistency because of significant relationship between SOM and soil consistency indicators including plastic limit (PL), liquid limit (LL), plasticity index (PI) and liquidity index (LI). While, hydrodynamic characters and potential low clay content occurred in the soil treated with biomass ash during high moisture conditions. These findings suggest that the application of biomass ash improved the stability of soil aggregate, which improved the structural stability of degraded soil but may pose a risk to soil erosion by water force. 相似文献
13.
Zhang-Liu Du Jian-Kun Zhao Yi-Ding Wang Qing-Zhong Zhang 《Journal of Soils and Sediments》2017,17(3):581-589
Purpose
Biochar application is deemed to modify soil properties, but current research has been mostly conducted on the degraded land in tropical regions. Using six consecutive years of biochar field trial, we investigated effects of biochar on soil aggregates, structural stability, and soil organic carbon (SOC) and black C (BC) concentrations in aggregate fractions. The findings have important implications in managing soil structure and SOC sequestration in high fertility soils of the temperate areas.Materials and methods
The study had four treatments: control; biochar rate at 4.5 (B4.5) and biochar rate at 9.0 t ha?1 year?1 (B9.0); and straw return (SR). Soil samples were collected from 0–10-cm layer, and aggregate size distribution was determined with the wet-sieving method. Then, the mean weight diameter (MWD) of aggregates and the aggregate ratio (AR), i.e., the ratio of the >250 μm to the 53–250 μm size were calculated to assess the structural stability. Total SOC and BC concentrations in bulk soil (<2 mm) and separated fractions (i.e., >2000, 250–2000, 53–250, and <53 μm) were measured.Results and discussion
The B4.5 and B9.0 significantly increased macroaggregate (250–2000 μm) and MWD and AR indices relative to the control. Comparing to the SR, the improvements in soil aggregation under biochar treatments were limited. Additionally, more SOC in larger fractions (>2000, 250–2000, and 53–250 μm) and BC in extracted fractions under biochar soils were observed. These results implied that biochar addition enhanced both native SOC and BC physical protection by aggregation.Conclusions
Biochar application is effective in mediating soil aggregation, and thus improves both native SOC and BC stabilization in an intensive cropping system of North China.14.
Annette Prechtel Margit von Lützow Bernd Uwe Schneider Oliver Bens Claus G. Bannick Ingrid Kögel‐Knabner Reinhard F. Hüttl 《植物养料与土壤学杂志》2009,172(5):601-614
Uncertainties in estimates of soil carbon (C) stocks and sequestration result from major gaps in knowledge of C storage in soils, land‐use history, the variability of field measurements, and different analytical approaches applied. In addition, there is a lack of long‐term datasets from relevant land‐use systems. As in many European countries, a national database on soil organic carbon (SOC) including all relevant information for the determination of soil C stocks is likewise missing in Germany. In this paper, we summarize and evaluate the present state of knowledge on organic‐C contents/pools in soils of Germany and discuss the need for the acquisition and access to new data on soil organic carbon. Despite the number of agricultural sites under permanent soil monitoring, regional surveys on SOC, comprehensive ecosystem studies, and long‐term field experiments, there is a striking lack of data in Germany particularly with regard to agricultural soils. Apart from a missing standardization of methods and homogeneous baseline values, the implementation of a periodic, nation‐wide soil inventory on agricultural soils is required in order to simultaneously record information on land use, land‐use change, and agricultural practice. In contrast, the existing national inventory of forest soils provides information on C‐stock changes in forest soils, although there is some concern with regard to the representativeness of the sampling design to adequately address the problem of spatial heterogeneity and temporal variability. It is concluded that the lack of comprehensiveness, completeness, actuality, data harmonization, and standardized sampling procedures will further prevent the establishment of a SOC database in Germany with regard to the monitoring of trends in soil C pools and fluxes and the assessment of long‐term C‐sequestration potentials of soils under different land use. A future soil inventory should represent the heterogeneity of organic matter through functionally different SOC pools, topsoil characteristics as well as content, pool, and flux data for the deeper mineral‐soil compartments. 相似文献
15.
Yong Wang Shuqing Gao Cuilan Li Jinjing Zhang Lichun Wang 《Journal of Soils and Sediments》2016,16(7):1849-1857
Purpose
Under a global warming scenario, understanding the response of soil organic carbon fractions and aggregate stability to temperature increases is important not only for better understanding and maintaining relevant ecosystem services like soil fertility and crop productivity, but also for understanding key environmental processes intimately related with the maintenance of other regulatory ecosystem services like global climate change mitigation through carbon sequestration. An increase in temperature would accelerate the mineralization of soil organic carbon. However, the properties of organic carbon remained in soil after mineralization is not well known.Materials and methods
Mollisol was collected at 0–20-cm depth from maize (Zea mays L.) field in Northeast China. A 180-day incubation experiment was conducted at three different temperatures (10, 30, and 50 °C) under constant soil moisture (60 % water holding capacity). Soil samples were assayed for total organic carbon (TOC), water-soluble organic carbon (WSOC), easily oxidizable organic carbon (EOC), humic fractions carbon, aggregate-associated carbon, and water stability of aggregates. Elemental analysis and solid-state 13C nuclear magnetic resonance spectroscopy were used to characterize humic acid and humin fractions.Results and discussion
The contents of soil TOC, EOC, humic fractions carbon, and aggregate-associated carbon decreased with the increase in temperature. The proportion of 2–0.25-mm macroaggregate and the mean weight diameter (MWD) of aggregates also decreased. The C, H, N, S, alkyl C, and O-alkyl C contents of humic acid and humin decreased, whereas the O, aromatic C, and carbonyl C contents increased. The H/C, aliphatic C/aromatic C, and O-alkyl C/aromatic C ratios in humic acid and humin fractions decreased.Conclusions
The increase in temperature has a negative impact on soil organic carbon content, soil aggregation, and aggregate stability. Moreover, humic acid and humin molecules become less aliphatic and more decomposed with the increase in temperature.16.
柑橘园土壤墒情远程监控系统设计与实现 总被引：4，自引：0，他引：4
针对传统的土壤墒情监测手段存在的监测范围小、采样率低等不足,设计实现了基于ZigBee无线传感网络和J2EE三层B/S架构技术的柑橘园土壤墒情远程监控系统。系统采用具有ZigBee无线数据传输功能的XBee-PRO模块和ECH2O型土壤水分传感器EC-5为核心组成传感器节点,部署于柑橘园的各个采集点对土壤墒情信息进行采集、预处理和无线发送等工作,通过基于ARM9的嵌入式网关与Internet网络连接,采集数据传输至远程Web主机,通过远程监控中心系统实现对采集数据分析处理和系统运行的远程和实时监控。进行了不同距离的传感器节点发送数据包的耗时和数据包发送成功率试验,在1 km以内耗时低于100 ms,数据包发送成功率高于98%。试验结果表明,系统实现了稳定可靠的数据传输,适合柑橘园土壤墒情的远程和实时监控。 相似文献
17.
Indigenous Australian earthworms comprise a patchily collected taxon that is likely to have high diversity and pose difficulties for systems of biodiversity prediction or monitoring that use surrogates. This is because surrogates for earthworm diversity have scarcely been identified at landscape scales in Australian contexts. In the present paper we examine the diversity of earthworms in a 26 km2 remnant of native vegetation. Comparison of diversity within the Porongurup Range to diversity of other earthworm faunas demonstrates the sampling intensities required to adequately sample regions of 100–101 km2. In addition diversity patterns were examined in relation to habitat as described by landscape context, vegetation cover and soil characteristics. Species accumulation in samples from the northern aspect of the Porongurup Range was less than expected from a random distribution of species. Combined Karri-, and Marri- and Karri-vegetated sites supported significantly more earthworm species on the southern aspect of the Porongurup Range than expected from accumulation in randomly ordered samples. Sites carrying Jarrah as the only dominant canopy had fewer earthworm species than would be expected from accumulation in randomly ordered samples. Jarrah overstorey sites and southern aspect Karri sites correspond to extremes in a continuum of soil and landscape characteristics. Earthworm responses to landscape and vegetation units in the region warrant further investigation. 相似文献
18.
《Communications in Soil Science and Plant Analysis》2012,43(17-18):2517-2528
Abstract An interagency forest monitoring program has been initiated on a systematic network of forested plots often accessible only by foot traffic along a compass line. Extensive site classification and physiochemistry data are being collected for vegetation and soil indicators of forest health. In order to select a suitable technique for obtaining an estimate of mineral soil bulk density, conventional clod and core methods were compared across a wide range of forest soils within the Coastal Plain of southeastern Virginia. Replicate soil clods and cores were collected from two to four horizons within each of six pedons representing different soil series. Following analysis, the sample data were used to evaluate main and interaction effects due to differences in the method, series, horizon, and texture effects. Differences between the clod and core data were highly significant on average (P < 0.001) as were all of the main effects. Both methods exhibited high precision (average CV < 5%) within the individual horizons sampled. The two data sets were highly correlated (r = 0.98), and the regression equation used to predict clod bulk density with data from the core method is: Clod BD = (1.011 x Core BD) + 0.068; standard errors of ±0.042 and ±0.048 for the slope and intercept, respectively. From an operational standpoint, the core method appears to have many advantages over the clod method for sampling in remote locations. 相似文献
19.
Soil data acquisition and assessment are crucial phases in the evaluation of soil degradation scenarios. To overcome the lack of field data, flexible sampling approaches can be used to complement conventional soil sampling. For the assessment of soil quality, it is necessary to integrate different soil support data and to provide a coherent spatial characterization of soil properties. This study proposes a new model to combine soil data from two different supports: “point” data, which refers to the concentration measured in the topsoil layer, and “bulk” data, which refers to the concentration measured for the whole soil depth sampled. The method developed uses a geostatistical co-simulation algorithm based on the experimental bi-distribution between both types of soil supports to compute co-simulated values. This new approach was applied to assess Soil Organic Carbon (SOC) availability in the topsoil. The results were used to identify critical areas in the Left Margin of the Guadiana River; an area in the South of Portugal with a high susceptibility to desertification. 相似文献
20.