共查询到20条相似文献，搜索用时 15 毫秒
1.
Stability and saturation of soil organic carbon in rice fields: evidence from a long-term fertilization experiment in subtropical China 总被引：1，自引：1，他引：0
Purpose
Soil organic carbon (SOC) sequestration in croplands plays a critical role in climate change mitigation and food security, whereas the stability and saturation of the sequestered SOC have not been well understood yet, particularly in rice (Oryza sativa L.) fields. The objective of this study was to determine the long-term effect of inorganic fertilization alone or combined with organic amendments on SOC stability in a double rice cropping system, and to characterize the saturation behavior of the total SOC and its fractions in the paddy soil.Materials and methods
Soils were collected from a long-term field experiment in subtropical China where different fertilization regimes have been carried out for 31 years. The total SOC pool was separated into four fractions, characteristic of different turnover rates through chemical fractionation. Annual organic carbon (C) inputs were also estimated by determining the C content in crop residues and organic amendments.Results and discussion
Relative to the initial level, long-term double rice cropping without any fertilizer application significantly increased SOC concentration, suggesting that double rice cropping facilitates the storage and accumulation of SOC. The partial substitution of inorganic fertilizers with organic amendments significantly increased total SOC concentration compared to the unfertilized control. Total SOC increased significantly with greater C inputs and did not show any saturation behavior. Increased SOC was primarily stored in the labile fraction with input from organic amendments. However, other less labile SOC fractions showed no further increase with greater C inputs exhibiting C saturation.Conclusions
While the paddy soil holds a high potential for SOC sequestration, stable C fractions saturate with increasing C inputs, and thus, additional C inputs mainly accumulate in labile soil C pools. 相似文献2.
This work sets out to verify whether the application of municipal solid waste compost (MSWC) or treated urban sewage sludge (USS) organic amendments efficiently promote organic matter (OM) increases in a Haplic Podzol (PZha) and in a Calcic Vertisol (VRcc). For that purpose, carbon (C) mineralization and C kinetic parameters were studied, using a laboratory experimental incubation setup. The results showed that the addition of the amendments to the soils increased their mineralization capacities, and that the highest C mineralization rate was reached at the end of the first 2 d of incubation. The different characteristics of the soils seem to have influenced the C mineralization rates during the 28-d incubation. The USS induced higher C mineralization than the MSWC, and the PZha soil gave rise to higher C mineralization than VRcc. For all treatments, C mineralization adjusted well to an exponential plus linear kinetic model, suggesting that the organic C of the amendments was made up of two organic pools of differing degrees of stability. With the exception of the application of USS 60 t ha−1, all the treatments increased the OM content on both soils, or at least the OM remained constant throughout the incubation. 相似文献
3.
Electron transfer capacity of soil dissolved organic matter and its potential impact on soil respiration 总被引：1，自引：0，他引：1
Purpose
Soil dissolved organic matter (DOM) as the labile fraction of soil organic carbon (SOC) is able to facilitate biogeochemical redox reactions effecting soil respiration and carbon sequestration. In this study, we took soil samples from 20 sites differing in land use (forest and agriculture) to investigate the electron transfer capacity of soil DOM and its potential relationship with soil respiration.Materials and methods
DOM was extracted from 20 soil samples representing different land uses: forest (nos. 1–12) and agriculture (nos. 13–20) in Guangdong Province, China. Chronoamperometry was employed to quantify the electron transfer capacity (ETC) of the DOM, including electron acceptor capacity (EAC) and electron donor capacity (EDC), by applying fixed positive or negative potentials to a working electrode in a conventional three-electrode cell. The reversibility of electron accepting from or donating to DOM was measured by applying switchable potentials to the working electrode in the electrochemical system with the multiple-step potential technique. Carbon dioxide produced by soil respiration was measured with a gas chromatograph.Results and discussion
Forest soil DOM samples showed higher ETC and electron reversible rate (ERR) than agricultural soil DOM samples, which may be indicative of higher humification rate and microbial activity in forest soils. The average soil respiration of forest soil (nos. 1–12) and agricultural soil (nos. 13–10) was 26.34 and 18.58 mg C g?1 SOC, respectively. Both EDC and EAC of soil DOM had close relationship with soil respiration (p?<?0.01). The results implied that soil respiration might be accelerated by the electroactive moieties contained in soil DOM, which serve as electron shuttles and facilitate electron transfer reactions in soil respiration and SOC mineralization.Conclusions
DOM of forest soils showed higher ETC and ERR than DOM of agricultural soils. As soil represents one of the largest reservoirs of organic carbon, soil respiration affects C cycle and subsequently CO2 concentration in the atmosphere. As one of the important characteristics of soil DOM related to soil respiration, ETC has a significant impact on greenhouse gas emission and soil carbon sequestration but has not been paid attention to. 相似文献4.
生物质改良剂对川西北地区高寒草地沙化土壤有机碳特征的影响 总被引：1，自引：0，他引：1
川西北高寒草原特殊的地理环境、气候条件以及过度人为放牧导致草地沙化问题突出。为了探讨不同生物质改良剂对高寒草地沙化土壤有机碳特征的影响,采用随机区组试验设计方法,设置3种生物质改良剂[秸秆类(JG)、菌渣类(JZ)、生物炭类(SWT)], 2个施用水平(6 t·hm?2和18 t·hm?2),以空白处理(CK)为对照,研究高寒草地沙化土壤总有机碳、活性有机碳和呼吸特征的变化。结果表明:1)施用生物质改良剂显著提高了土壤有机碳(TOC)、微生物量碳(MBC)和易氧化有机碳(EOC)含量,且提高效果随改良剂施用量的增加而增强。与CK相比,JG、JZ、SWT处理0～10 cm TOC含量分别平均提高60.66%、39.22%、34.99%,且JG处理显著高于JZ和SWT处理; MBC含量在0～10 cm则表现为JZJGSWTCK,且处理间差异达显著水平; EOC含量表现为JG处理最高,在0～10 cm、10～20 cm土层处分别比对照提高108.82%、79.26%。2)不同生物质改良剂处理中, EOC/TOC表现为JGJZSWTCK,MBC/TOC表现为JZJGSWTCK,且不同处理间差异显著。3)施用不同改良剂均显著提高了土壤呼吸速率,且随改良剂施用量的增加,土壤呼吸速率显著增加。与CK相比,施用6 t·hm?2的JG、JZ、SWT的土壤呼吸速率平均提高103.42%、86.31%、18.83%, JZ和JG处理的土壤呼吸速率显著高于SWT和CK处理。相关性分析表明,土壤水分与土壤呼吸速率呈显著正相关关系, TOC、MBC以及EOC与土壤呼吸速率呈极显著正相关关系。4)施入不同改良剂均显著提高了土壤呼吸总量、土壤微生物呼吸总量和净生态系统生产力(NEP值),均表现出较强的碳汇潜力, JG处理的NEP值较JZ和SWT处理分别显著提高56.45%和122.12%,且各处理间差异显著,说明秸秆改良剂具有较高的碳汇强度。该研究可为川西北藏区补充完善高寒草地沙化土壤制定科学有效的土壤碳调控管理措施提供依据。 相似文献
5.
Anton A. Gasser Julius Diel Kerstin Nielsen Paul Mewes Christof Engels Uwe Franko 《Soil Use and Management》2022,38(1):179-190
Organic amendments are important to sustain soil organic matter (SOM) and soil functions in agricultural soils. Information about the contribution of organic amendments to SOM can be derived from incubation experiments. In this study, data from 72 incubated organic amendments including plant residues, digestates and manure were analysed. The incubation data was compiled from three experimental setups with varying incubation times, soils and incubation temperatures, in which CO2 release was measured continuously. The analysis of the incubation data was performed with an approach relying on conceptual parts of C-TOOL, CCB, Century, ICBM, RothC and Yasso which are all well-approved first-order carbon models that differ in structure and abstraction level. All models are an approximation of reality, whereby each model differs in understanding of the processes involved in soil carbon dynamics. To accumulate the advantages from each model a model ensemble was performed for each substrate. With the ability of each carbon model to compute the distribution of carbon into specific SOM pools a new approach for evaluating organic amendments in terms of humus building efficiency is presented that, depends on the weighted model fit of each ensemble member. Depending on the organic substrate added to the soil, the time course of CO2 release in the incubation studies was predicted with different accuracy by the individual model concepts. Averaging the output of the individual models leads to more robust prediction of SOM dynamics. The EHUM value is easy to interpret and the results are in accordance with the literature. 相似文献
6.
Stabilized municipal sewage sludge addition to improve properties of an acid mine soil for plant growth 总被引：1，自引：0，他引：1
M. D. Mingorance S. Rossini Oliva Benito Valdés F. J. Pina Gata Eduardo O. Leidi I. Guzmán Aránzazu Peña 《Journal of Soils and Sediments》2014,14(4):703-712
Purpose
Degraded soils, such as those encountered in areas of mine activities, need to be ameliorated by liming to correct soil acidity and by addition of organic inputs to improve soil properties and fertility.Materials and methods
Non-amended mine soil and soil amended with stabilized sewage sludge were incubated for 45 days. Soil physicochemical and biological indicators were periodically measured along incubation and other enzyme activities at the end of incubation. In improved soils, a study of plant development in 250-g pots was carried out with three vegetal species: tomato, rye grass and ahipa. Germination and mortality rates, biomass production and photosynthetic pigments were measured.Results and discussion
Soil incubation with sewage sludge slightly increased soil pH and led to an enhancement of soil electrical conductivity, organic carbon and dehydrogenase activity, especially for the higher doses (5 and 10%). However soil respiration was more promoted with the 2% dose, pointing to a possible toxic effect of the sludge. At the end of incubation, physicochemical and biological properties were in general enhanced. Biomass production was improved in tomato and rye grass by sewage sludge addition (more at the 2% dose), whilst ahipa growth was not affected by sewage sludge treatments. Tomato mortality reached 73% with high sludge doses (10%).Conclusions
According to this set of parameters, amendment with sewage sludge of a limed acid mine soil would be considered as a good strategy for soil amelioration in view of plant establishment and development. 相似文献7.
Jolanta Kwiatkowska-Malina 《Journal of Soils and Sediments》2018,18(8):2801-2812
Purpose
The aims of this paper were to review tools and methods for qualitative and quantitative evaluation of soil organic matter (SOM) coming from diverse egzogenic sources for effective soil management, and to introduce a new approach to predict dynamics of SOM transformations, especially humification, as a key process in the formation of humic substances (HSs).Materials and methods
A review of existing literature is presented on tools and methods for qualitative and quantitative assessment of organic matter in soil originating from various sources for reasonable soil management, attempting to provide a better understanding of the advances in organic matter transformations and new research directions for modeling. Diverse tools and methods for qualitative and quantitative evaluation of organic matter in soil coming from diverse sources have been adopted so far to express transformation processes.Results and discussion
For the qualitative analysis of SOM and humic acids (HAs), the analytical techniques are applied, e.g., HPSEC, NMR, and ESI-FTICRMS. The quantitative analysis is done through the following parameters: humification index (HI), humification degree (HD), and humification rate (HR). These analyses indicated that because of lack of reliable data from sufficiently long-term experiments, mathematical modeling may be applied as a numerical tool for quantitative estimation and prediction of humification of SOM. The effective soil management should include soil properties as well as different functions: food production, nutrient and water cycling, storage, filtrating, buffering, biological habitat, gene pool, source of raw materials, climate regulations, heritage, platform for man-made structure. The soil utility value should be evaluated through the SOM qualitative and quantitative analysis of organic carbon and total nitrogen. Knowledge about dynamics of SOM transformations is essential, particularly in the context of stability and efficiency of different sources of organic matter applied into soil. A qualitative understanding of SOM dynamics transformations along with modeling for quantitative assessment of HS formation should be used to develop sustainable soil management. The modeling may be considered as a tool for predicting SOM humification dynamics and consequently the formation of HSs from the diverse sources. The existing archival data from a long-term experiment may be used to build and calibrate the reliable mathematical model of SOM humification.Conclusions
Managing of SOM remains a sound basis for maintaining soil in a good condition for optimizing productivity. The development of land management strategies to optimize both the increase of soil organic carbon levels and the recycling of nutrients from SOM needs to be a priority. This should include policy makers and other users as well.8.
Purpose
Peatland soils play an important role in the global carbon (C) cycle due to their high organic carbon content. Lowering of the water table e.g. for agricultural use accelerates aerobic secondary peat decomposition and processes of earthification. Peatlands change from C sinks to C sources. We characterized soil organic matter (SOM) with special attention to human impact through drainage. Our aim was to gain knowledge of SOM quality and soil-forming processes in drained fen soils in northeastern Germany.Materials and methods
Through techniques of representative landscape analysis, we identified two typical and representative sampling sites in different stages of land use, representing the most important hydrogenetic mire types in northeastern Germany. We adapted chemical fractionation procedures which include hot water extraction (Chwe and Nhwe) for determination of the labile fraction. Furthermore, a stepwise acid hydrolysis procedure was performed to measure the chemical recalcitrant part of SOM as it is more resistant to biodegradability.Results and discussion
Total organic C decreased with increasing human impact and intensity of drainage. Conversely, Chwe and Nhwe concentrations increased with increasing drainage and human impact. In contrast, the more recalcitrant fractions increased with soil depth.Conclusions
Generally, there is a lack of existing data about SOM quality and the factors controlling its stability and decomposition in fen soils. For northeastern German fen soils, the data are even more inadequate. Influence of drainage seems to overlap natural influences of site on SOM quality. The used extraction scheme was suitable for the chemical fractionation of SOM into labile and more recalcitrant parts. 相似文献9.
Purpose
Cover crop residue is generally applied to improve soil quality and crop productivity. Improved understanding of dynamics of soil extractable organic carbon (EOC) and nitrogen (EON) under cover crops is useful for developing effective agronomic management and nitrogen (N) fertilization strategies.Materials and methods
Dynamics of soil extractable inorganic and organic carbon (C) and N pools were investigated under six cover crop treatments, which included two legume crops (capello woolly pod vetch and field pea), three non-legume crops (wheat, Saia oat and Indian mustard), and a nil-crop control (CK) in southeastern Australia. Cover crops at anthesis were crimp-rolled onto the soil surface in October 2009. Soil and crop residue samples were taken over the periods October?CDecember (2009) and March?CMay (2010), respectively, to examine remaining crop residue biomass, soil NH4 +?N and NO3 ??CN as well as EOC and EON concentrations using extraction methods of 2?M KCl and hot water. Additionally, soil net N mineralization rates were measured for soil samples collected in May 2010.Results and discussion
The CK treatment had the highest soil inorganic N (NH4 +?N?+?NO3 ??CN) at the sampling time in December 2009 but decreased greatly with sampling time. The cover crop treatments had greater soil EOC and EON concentrations than the CK treatment. However, no significant differences in soil NH4 +?N, NO3 ??CN, EOC, EON, and ratios of EOC to EON were found between the legume and non-legume cover crop treatments across the sampling times, which were supported by the similar results of soil net N mineralization rates among the treatments. Stepwise multiple regression analyses indicated that soil EOC in the hot water extracts was mainly affected by soil total C (R 2?=?0.654, P?<?0.001), while the crop residue biomass determined soil EON in the hot water extracts (R 2?=?0.591, P?<?0.001).Conclusions
The cover crop treatments had lower loss of soil inorganic N compared with the CK treatment across the sampling times. The legume and non-legume cover crop treatments did not significantly differ in soil EOC and EON pools across the sampling times. In addition, the decomposition of cover crop residues had more influence on soil EON than the decomposition of soil organic matter (SOM), which indicated less N fertilization under cover crop residues. On the other hand, the decomposition of SOM exerted more influence on soil EOC across the sampling times among the treatments, implying different C and N cycling under cover crops. 相似文献10.
David Tokarski Jiří Kučerík Karsten Kalbitz Michael Scott Demyan Ines Merbach Dietmar Barkusky Joerg Ruehlmann Christian Siewert 《植物养料与土壤学杂志》2018,181(5):664-674
Sustainable soil management requires reliable and accurate monitoring of changes in soil organic matter (SOM). However, despite the development of improved analytical techniques during the last decades, there are still limits in the detection of small changes in soil organic carbon content and SOM composition. This study focused on the detection of such changes under laboratory conditions by adding different organic amendments to soils. The model experiments consisted of artificially mixing soil samples from non‐fertilized plots of three German long‐term agricultural experiments in Bad Lauchstädt (silty loam), Grossbeeren (silty sand), and Müncheberg (loamy sand) with straw, farmyard manure, sheep faeces, and charcoal in quantities from 3 to 180 t ha?1 each. In these mixtures we determined the organic carbon contents by elemental analysis and by thermal mass losses (TML) determined by thermogravimetry. The results confirmed the higher reliability of elemental analysis compared to TML for organic carbon content determination. The sensitivity of both methods was not sufficient to detect the changes in organic carbon content caused by small quantities of organic amendments (3 t ha?1 or 0.1–0.4 g C kg?1 soil). In the case of elemental analysis, the detectability of changes in carbon content increased with quantities of added amendments, but the method could not distinguish different types of organic amendments. On the contrary, the based on analysis of degradation temperatures, the TML allowed this discrimination together with their quantitative analysis. For example, added charcoal was not visible in TML from 320 to 330°C, which is used for carbon content determination. However, increasing quantities of charcoal were reflected in a higher TML around 520°C. Furthermore, differences between measured (with TML110–550) and predicted mass loss on ignition using both organic carbon (with TML330) and clay contents (with TML140) were confirmed as a suitable indicator for detection of organic amendments in different types of soils. We conclude that thermogravimetry enables the sensitive detection of organic fertilizers and organic amendments in soils under arable land use. 相似文献
11.
Wenju Zhang Minggang Xu Xiujun Wang Qinhai Huang Jun Nie Zuzhang Li Shuanglai Li Seon Woong Hwang Kyeong Bo Lee 《Journal of Soils and Sediments》2012,12(4):457-470
Purpose
Although organic amendments have been recommended as one of the practices for crop production and soil carbon sequestration, little has been done to evaluate soil organic carbon (SOC) dynamics following long-term application of organic amendments. The objective of this research were to (1) assess the effect of long-term organic amendments on SOC dynamics in rice-based systems; (2) evaluate the relationship between soil carbon sequestration and carbon input based on various mineral and organic fertilization treatments. 相似文献12.
Purpose
This study aims to evaluate the effects of industrial and agricultural by-products as amendments on soil acidity, soil nutrients, enzymatic and microbial properties, and thus soil quality of an acidic Ultisol under field conditions and to give some index for choosing amendments in acid soils.Materials and methods
A long-term field experiment was established in an acidic Ultisol in the middle China to investigate the ameliorating effect after application of industrial and agricultural by-products for 4 years. There were five treatments including addition of rice chaff, peanut straw, alkaline slag, alkaline slag with rice chaff, and without amendment of control. Top soil samples (0–15 cm) from individual plots per treatment were collected for the analysis of chemical and microbial properties. The relationships between chemical properties and microbial and enzymatic properties were also analyzed with bivariate correlation analyses and stepwise linear regression.Results and discussion
Alkaline slag was more effective than rice chaff and peanut straw in correcting soil acidity and induced more increase in catalase activity, acid phosphatase activity, and microbial quotient, and thus more depress in the metabolic quotient, since soil acidity was an important stress factor for microbial and enzyme activities in the Ultisol. Incorporation of rice chaff and peanut straw markedly increased the soil microbial carbon, urease activity, and basal respiration to a greater extent, by more greatly enriching soil with organic carbon and more balanced nutrients of N, P, and K, which were also significant factors affecting microbial properties. Consequently, the application of alkaline slag and rice chaff together was the most effective in enhancing the geometric mean of enzyme activities (an important index of soil quality) when compared with the single application of alkaline slag, rice chaff, or peanut straw.Conclusions
Soil acidity, organic C, and balanced nutrients of N, P, and K were key factors for affecting soil microbial and enzymatic activities, and thus soil quality in this Ultisol. The combined industrial and agricultural by-products together as amendments would be the better choice to improve soil quality in acidic Ultisols. 相似文献13.
Impact of long-term application of manure,crop residue,and mineral fertilizer on organic carbon pools and crop yields in a Mollisol 总被引：1，自引：0，他引：1
Xueli Ding Yaru Yuan Yao Liang Lujun Li Xiaozeng Han 《Journal of Soils and Sediments》2014,14(5):854-859
Purpose
While the influence of integrated fertility management systems on yield and N cycling in Mollisols is documented, its effect on soil C sequestration remains to be determined. We examined the response of organic C pools and crop yields to 21 years’ organic amendments applied at relatively low rates in a high-C Mollisol to optimize win–win management practices that balance agronomic and environmental interests.Materials and methods
This study was based on five treatments: CK (unfertilized control), NPK (chemical fertilizer alone), NPKS1 (NPK plus crop residues), NPKS2 (NPK plus double amounts of crop residues), and NPKM (NPK plus pig manure). Crop yield was determined by harvesting a defined area. Organic C was quantified by dry combustion. A two-step acid hydrolysis technique was used to quantify hydrolysable and non-hydrolysable C fractions.Results and discussion
All organic-treated plots produced significantly higher crop yields than the NPK plots, but only the manure treatment resulted in a significant increase in SOC compared with the NPK treatment after 21 years of experiment. It seems that the effects of organic amendments on SOC depend primarily on the type of organic materials when the application rates were relatively low. This indicated that organic amendments offer relatively short-term soil benefits for plant growth. The pig manure builds SOC over the long term, which provides secondary benefits while also sequestering C.Conclusions
Overall, manure integrated with mineral fertilizer should be recommended to maintain the SOC content and increase crop yield in the Mollisols. 相似文献14.
Defining soil geochemical baselines at small scales using geochemical common factors and soil organic matter as normalizers 总被引：1，自引：0，他引：1
Zhigang Wang Jeremy Landon Darilek Yongcun Zhao Biao Huang Weixia Sun 《Journal of Soils and Sediments》2011,11(1):3-14
Purpose
The establishment of geochemical baselines is essential for accurate evaluation of the present state of surface environments. In this study, normalization procedures (NP), which can improve the explanation of the natural variation of elements, were conducted using geochemical common factors (GCF) and soil organic matter (SOM) as normalizers to define the geochemical baselines of soil trace elements.Materials and methods
Soil samples (n?=?345) were collected in Luhe County, Jiangsu, China, a county with a complex geologic setting and intensive anthropogenic influence. Conservative elements, Al, Ca, Fe, K, Mg, Mn, Na, P, and Ti; trace elements, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; and SOM were measured. Normalization procedures were conducted using multiple linear regressions between soil trace elements and SOM and GCFs, acquired from factor analysis of the soil major elements. Normalization procedures using univariate linear regressions between soil trace elements and conservative elements Al, Fe, and Ti were also conducted for comparison.Results and discussion
Comparison of NPs using GCFs and SOM as normalizers with NPs, which use single conservative elements as normalizers, shows that the former is more accurate than the latter for As, Pb, and Zn and is as accurate for Cd, Cr, Cu, Hg, and Ni, when the most appropriate single conservative element is chosen. Small-scale geochemical baselines in the county are significantly different from regional-scale geochemical baselines for Jiangsu Province, China.Conclusions
The application of regional-scale geochemical baselines at small scales may lead to estimation errors in determining anomalies and assessing environments. Baselines obtained from the NPs using GCFs and SOM as normalizers are more accurate. 相似文献15.
The response of soil organic matter to manure amendments in a long-term experiment at Ultuna, Sweden 总被引：2，自引：0，他引：2
M.H. GERZABEK F. PICHLMAYER H. KIRCHMANN G. HABERHAUER 《European Journal of Soil Science》1997,48(2):273-282
In a long-term field experiment started in 1956 on a clay loam soil at Uppsala, Sweden, changes of organic carbon in the topsoils receiving various organic amendments at the rate of 200 kg C ha'1 year'1 were studied to determine soil organic matter characteristics, variations of δ13C in the soil and to estimate a carbon balance. Fallow and mineral fertilizer without N led to a significant decrease of soil organic matter (SOM) in the soil, green manure maintained the SOM content, and animal manure and peat increased the SOM content significantly. The stable portion of the added organic materials after 37 years of continuous input was 12·8, 27·3, and 56·7%, for green manure, animal manure and peat, respectively. This was reflected by half-lives of organic carbon originating from the amendments between 3·0 (green manure) and 14·6 years (peat). The isotopic composition of SOM changed both due to mineralization (continuous fallow) and the addition of amendments is topically different from soil humus (green manure, animal manure). The isotopic effect was used to calculate the percentage of carbon derived from animal manure present for the year 1993. This value (55·4%) was larger than that derived from the carbon balance, which indicated a priming effect of the animal manure on the initial soil humus. Mineralization of microbially available organic substances led to an increase in the degree of humification on plots not receiving organic amendments. Adding peat and animal manure resulted in a decrease of the humification index due to the continuous input of poorly humified material. The extinction ratio (E4/E6) and ratio of fulvic acid to humic acid changed considerably in the peat treated plots. Fourier transform infrared (FTIR)-measurements of the extracts showed that peat characteristics can be detected in peat treated soils. The other amendments did not alter the characteristics of the extractable humic substances. 相似文献
16.
Gunnar Börjesson Holger Kirchmann Thomas Kätterer 《Journal of Soils and Sediments》2014,14(1):164-177
Purpose
This study aims to study the effect of sewage sludge amendment on crop yield and on microbial biomass and community structure in Swedish agricultural soils.Materials and methods
Topsoil samples (0–0.20 m depth) from four sites where sewage sludge had been repeatedly applied during 14–53 years were analysed for total C, total N, pH and phospholipid fatty acids (PLFAs). Heavy metals were analysed in both soil and plant samples, and crop yields were recorded.Results and discussion
At all four sites, sewage sludge application increased crop yield and soil organic carbon. Sludge addition also resulted in elevated concentrations of some heavy metals (mainly Cu and Zn) in soils, but high concentrations of metals (Ni and Zn) in plant materials were almost exclusively found in the oldest experiment, started in 1956. PLFA analysis showed that the microbial community structure was strongly affected by changes in soil pH. At those sites where sewage sludge had caused low pH, Gram-positive bacteria were more abundant. However, differences in community structure were larger between sites than between the treatments.Conclusions
At all four sites, long-term sewage sludge application increased the soil organic carbon and nitrogen content, microbial biomass and crop yield. Long-term sewage sludge application led to a decrease in soil pH. Concentrations of some metals had increased significantly with sewage sludge application at all sites, but the amounts of metals added to soil with sewage sludge were found not to be toxic for microbes at any site. 相似文献17.
Gabriele E. Schaumann Daniela Gildemeister Yamuna Kunhi Mouvenchery Sandra Spielvogel Dörte Diehl 《Journal of Soils and Sediments》2013,13(9):1579-1588
Purpose
Nutrient release, soil wettability, water binding, and matrix rigidity of soil organic matter (SOM) can be affected by cross-links between segments of SOM, cations, and water molecule bridges (WaMB). Not all cation effects on SOM can be explained with the currently accepted idea that multivalent cations cross-link organic matter segments via direct cation bridges (CaB). The objective was to understand these interactions and their effect on SOM matrix rigidity and wettability.Materials and methods
We modified cation composition of two peats and an organic surface layer (OSL) using cation exchange resin to remove cations and solutions of Na+, Ca2+, or Al3+ to enrich samples with cations. SOM matrix rigidity was determined at 4 and >8 weeks after treatment via the WaMB transition temperature T*, using differential scanning calorimetry. Wettability was measured via sessile drop contact angle (CA).Results and discussion
The effect of cation removal on T* depended on cation exchange capacity and initial cation content. Cation addition to OSL increased T*. This effect increased with increasing cation loading and valency, and T* correlated with CA. Classical cross-linking can neither explain the higher heterogeneous matrix of Ca-treated than Al-treated samples nor the aging-induced convergence of T* for different cations and concentrations. The latter is likely due to interaction between CaB and WaMB in SOM.Conclusions
Associations of CaB and WaMB evolve slowly and form a supramolecular network in SOM. Those dynamic associations can fix molecular arrangements inducing water repellency and increase kinetic barriers for the release and uptake of water and nutrients from aged soil. 相似文献18.
Short-term evolution of hydration effects on soil organic matter properties and resulting implications for sorption of naphthalene-2-ol 总被引：1，自引：1，他引：0
Tatjana Schneckenburger Gabriele E. Schaumann Susanne K. Woche S?ren Thiele-Bruhn 《Journal of Soils and Sediments》2012,12(8):1269-1279
Purpose
Sorption of xenobiotics in soils and especially to soil organic matter (SOM) determines their mobility and bioavailability in ecosystems. However, SOM as the major sorbent may be altered in its physicochemical properties upon changes in boundary conditions such as hydration. Hence, the goal of this study was to determine the influence of soil hydration on physicochemical properties of SOM and the resulting effects on sorption of xenobiotics.Materials and methods
Samples of a Histosol with 51?% SOM were adjusted to five water contents from 10 to 75?% (w/w based on dry soil mass) and aged for water contact times of 0?weeks to 3?years. The hydrated samples were characterized with respect to thermal properties of SOM and of the incorporated water via differential scanning calorimetry and with respect to hydration-induced swelling via 1H-NMR relaxometry, and the sessile drop method was applied to determine their soil?Cwater contact angle. Sorption kinetics and isotherms of naphthalene-2-ol in the pre-treated peat samples were determined in batch experiments.Results and discussion
SOM matrix rigidity varied with the water content and increased with water contact time. An initial minimum in SOM rigidity at ~30?% water content became maximum after ~20?weeks, also resulting in the strongest resistance towards water infiltration. We argue that the anomalies at 30?% water content are related to the critical water content for the formation of freezable water w crit in the peat samples, which was 26.2?±?0.3?%. Conditions for water-assisted molecular bridging were assumably optimal at 30?% water content. Whereas parameters of naphthalene-2-ol sorption reflecting the sorbed amount were mainly altered by the wetting properties of SOM, sorption linearity and hysteresis were influenced by the anomalies in peat matrix properties at a water content around 30?%.Conclusions
The study revealed that the interplay of SOM and water led to highly variable and complex changes in SOM physicochemical properties. These properties may serve as a predictor for sorption of xenobiotics in soil at varying hydration conditions enabling a more precise assessment of the environmental fate of xenobiotics. 相似文献19.
Yun Zhang Zhichao Wei Huitong Li Futao Guo Pengfei Wu Lili Zhou Xiangqing Ma 《Journal of Soils and Sediments》2017,17(9):2218-2229
Purpose
Biochemical protection is an important mechanism for maintaining the long-term stability of the soil carbon (C) pool. The labile and recalcitrant pools of soil organic matter (SOM) play different roles in regulating C and N dynamics; however, few studies have characterized the capacity of soil C sequestration while considering the biochemical quality of SOM. The aim of the present study was to assess the changes in the soil organic carbon (SOC) and nitrogen (N) pools during a traditional rotation period (25 years) of a Chinese fir (Cunninghamia lanceolata) plantation with an emphasis on SOM biochemical quality.Materials and methods
Three different forest stand development stages—young (6 years old), middle-aged (16 years old) and mature (25 years old)—were selected for soil sampling to a depth of 100 cm. Total C and total N of the soil was analysed to determine the changes in the SOC and N stocks among the three development stages using an equivalent soil mass (ESM) approach. Bulk soils were fractionated into labile and recalcitrant fractions using the acid hydrolysis method to identify the quality of SOM.Results and discussion
The mineral soil organic carbon pool at a 1-m depth slightly decreased from the young stand to the middle-aged stand and rapidly increased by 28 % to reach a maximum in the mature stand. SOC accumulation in the surface soil predominated the changes in total SOC stocks in all three stands. The increased N was reflected in the entire depth, and the highest soil N accumulation was in the mature stand. The recalcitrant C concentration and SOC were positively correlated. The non-hydrolysable C proportion was lower in the middle-aged stand versus the young stand (8.69 % loss), while the labile C percentage was higher (13.89 % gain). In the mature stand, the recalcitrant C index increased to 39.84 %. The recalcitrant index of C decreased with an increasing soil depth, whereas the recalcitrant index of N dramatically increased.Conclusions
These results highlighted the significant effect of the stand age and the soil depth on the storage and biochemical availability of SOM in Chinese fir plantations of southern China. The recalcitrant index of C changed with the change in SOC concentration, indicating that biochemical protection mechanism plays an important role in soil C sequestration. In addition, more attention should be paid to subsoil C protection in the management of Chinese fir plantations because of low biochemical stability.20.
Nives Ogrinc Tjaša Kanduč Bor Krajnc Urša Vilhar Primož Simončič Lixin Jin 《Journal of Soils and Sediments》2016,16(2):382-395