受土壤类型和金属负荷量影响的重金属形态分布

Two series of soil subsamples, by spiking copper(Cu),lead(Pb),zinc(Zn)and cadmium(Cd)in an orthogonal design,were prepared using red soil and brown soil,respectively.The results indicated that heavy metal fractions in these soil subsamples depended not only on soil types,but also on metal loading quantity as well as on interactions among metals in soil.Lead and Cu in red soil appeared mostly in weakly specifically adsorbed(WSA),Fe and Mn oxides bound(OX),and residual(RES)fractions.Zine cxisted in all fractions except organic bound one,and Cd was major in water soluble plus exchangeable(SE)one.Different from the results of red soil,Pb and Cu was present in brown soil in all fractions except organic one,but over 75% of Zn and 90% of Cd existed only in SE fraction.Meanwhile,SE fraction for any metal in red soil was lower than that in brown soil and WSA and OX fractions were higher.It is in agreernent with low cation exchange capacity and large amounts of metal oxides included in red soil.Metal fractions in soil,especially for water soluble plus exchangeable one ,were obviously influenced by other coexisting metals.The SE fraction of heavy metals increased with increasing loading amounts of metals in red soil but not obviously in brown soil,which suggest that metal availability be easily affected by their total amounts spiked in red soil.In addition,more metals in red soil were extracted with 0.20 mol L^-1 NH4Cl（pH5.40）than that with 1.0 mol L^-1 Mg(NO3)2(pH7.0),but the reverse happened in brown soil,implicating significantly different mechanisms of metal desorption from red soil and brown soil.     

利用Technosols改善铜矿土壤的物理化学特性

Mine tailing soils created from the copper extraction in Touro Mine (Northwest Spain) are very degraded both physically and chemically. Three plots in this mine tailing were amended with Technosols in different proportions in each one to know if this mixture improved the physico-chemical characteristics of the mine soil and contaminated it with heavy metals. The Technosols were made of organic wastes, including mussel residues, wood fragments, sewage sludges and paper mill ashes. An unamended area was used as a control soil. Pseudototal and diethylenetriaminepentaacetic acid (DTPA)-extractable contents of Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in soil samples. The untreated soil had significant limitations for vegetation growth. All the Technosols improved the properties of the mine soil by increasing organic carbon and pH value, but they added Ni, Pb or Zn to the soil. It is advisable to check whether the heavy metal concentrations of the wastes are hazardous or not before adding to soils. It is also necessary to study the effect of these wastes over time and in more areas to conclude if they are actually favourable to restore degraded mine soils.     

树的年轮和土壤中元素含量的长期分布情况

Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the ^137Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer.     

亚热带湿润地区城市公园重建强度对其土壤酸化和土壤中重金属的影响

Soil quality is a major concern in the management of urban parks. In this study, the soils at 0–3, 3–13, and 13–23 cm depths were sampled from six urban parks, differing in reconstruction intensity(mainly changes made during conversion of natural forests into parklands), in the Pearl River Delta, China to determine how reconstruction intensity influenced the extent of acidification and heavy metal levels in the soils of urban parks in a humid subtropical environment. High reconstruction intensity(HRI) was practiced in three parks and low reconstruction intensity(LRI) in three other parks. The LRI soils were strongly to extremely acidic(with low exchangeable Ca, Mg, and K concentrations) while the HRI soils were much less acidic. Both total and extractable concentrations of soil heavy metals were related to the specific management practices and age of the park, but did not differ significantly between LRI and HRI parks or among soil depths. Soil p H was significantly related to soil exchangeable cation concentrations and base saturation but was weakly related or unrelated to soil heavy metal levels. Our results suggest that high intensity but not low intensity reconstruction significantly reduces the extent of soil acidification in the urban parks in a humid subtropical environment.     

土壤有机碳对沼渣或牛粪施用后温室气体排放潜力的影响—盆栽试验结果

A change in the European Union energy policy has markedly promoted the expansion of biogas production.Consequently,large amounts of nutrient-rich residues are being used as organic fertilizers.In this study,a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas (GHG) emissions following organic fertilizer application in energy maize cultivation.We hypothesized that cattle slurry application enhanced CO2 and N2O fluxes compared to biogas digestate because of the overall higher carbon (C) and nitrogen (N) input,and that higher levels of CO2 and N2O emissions could be expected by increasing soil organic C (SOC) and N contents.Biogas digestate and cattle slurry,at a rate of 150 kg NH4+-N ha-1,were incorporated into 3 soil types with low,medium,and high SOC contents (Cambisol,Mollic Gleysol,and Sapric Histosol,termed Clow,Cmedium,and Chigh,respectively).The GHG exchange (CO2,CH4,and N2O) was measured on 5 replicates over a period of 22 d using the closed chamber technique.The application of cattle slurry resulted in significantly higher CO2 and N2O fluxes compared to the application of biogas digestate.No differences were observed in CH4 exchange,which was close to zero for all treatments.Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types,whereas the highest N2O emissions were observed in Cmedium.Thus,the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.     

侵蚀引起的苏南坡地土壤退化

Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the ¹³⁷Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer.     

Effect of controlled-release urea on heavy metal mobility in a multimetal-contaminated soil

Controlled-release N fertilizers can affect the availability of heavy metals in the contaminated paddy soil.A soil incubation experiment was conducted to investigate the effects of prilled urea(PU),S-coated urea(SCU),and polymer-coated urea(PCU)on the solubility and availability of heavy metals Cd,Pb,Cu,and Zn in a multimetal-contaminated soil.The results showed that the application of different coated urea significantly affected the solubility and availability of heavy metals.At 5 d of incubation,the application of PU,SCU,and PCU had significantly decreased the concentrations of water-soluble and available Cd,Pb,Cu,and Zn,when compared with the control.At 60 d of incubation,the depletory effects of PU on water-soluble and available heavy metals had reduced,and the initial decrease in the concentrations of water-soluble Cd,Pb,Cu,and Zn caused by SCU had changed to an increase.The concentrations of water-soluble Pb,Cu,and Zn in the SCU-treated soil were higher than those in the control.Application with PCU led to a higher water-soluble Cu than that in the control,while the available Cd,Pb,and Zn were lower than those in the control.The effect of different coated urea was much stronger on the water solubility of the heavy metals than on their availability.The effects of controlled-release urea on the transformation of heavy metals resulted in changes in the concentrations of NH4^+,water-soluble SO4^2-,and soil p H.The results further suggested that PCU could be used in dry farming operations in multimetal-contaminated acid soils.     

红壤重金属的复合污染

The effects of combined heavy metal pollution of red soil on the growth of wetland rice and the transfer of Pb,Cd,Cu and Zn from soil into plants were sudied by greenhouse pot experiment,The results showed that the plantyields were markedly affected by heavy metals,with the exception of Pb,in soils under the experimental conditions,without taking into consideration all the interactions among the elements.The concentrations of the elemets in plants were mainly affected by the specific element added to the soil.The effect of interactions among the heavy metals was very significant either on plant yields or on the concentration of the elements in plants.The risk assessment of a combined pollution by heavy metals in the soil is discussed preliminarily in terms of the relative pollution equivalent.     

在温室和室外管理措施下有机和矿物肥料对土壤物理性质的长期效应研究

To evaluate the use of organic amendments as an alternative to conventional fertilization,a 10-year experiment on a loam soil was conducted under a crop rotation system in both greenhouse and outdoor plots applied with chemical fertilizers (NPK) and vegetal compost (organic fertilizer) in the Guadalquivir River Valley,Spain.The effect of these two different fertilization regimes on the soil physical properties was evaluated.Soil organic carbon (OC),soil bulk density (BD),soil water retention (WR),available water content (AWC),aggregate stability (AS),and soil physical quality (Dexter’s index,S) were determined.The use of organic fertilizer increased OC and resulted in a significant increase in AS and a decrease in BD compared to the mineral fertilizer application in both greenhouse and outdoor plots.The outdoor plots showed the lowest BD values whereas the greenhouse plots showed the highest AS values.In the last years of the 10-year experiment the S parameter was significantly higher in organic fertilizer plots,especially for greenhouse plots.At the end of the study period,there were no significant differences in WR at field capacity (FC) between treatments in both systems;the AWC was also similar in the greenhouse plots but higher in the mineral outdoor plots.In mineral fertilizer treatments,a small improvement in the physical properties was also observed due to the utilization of less aggressive tillage compared with the previous intensive cropping system.Physical soil properties were correlated with soil OC.The sustainable management techniques such as the use of organic amendments and low or no tillage improved soil physical properties,despite the differences in management that logically significantly affected the results.     

草甸草原模拟氮沉降抑制甲烷吸收、促进氧化亚氮排放

Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide (N2O) emission and methane (CH4) uptake in the meadow steppe of Inner Mongolia,China.A two-year field experiment was conducted to assess the effects of nitrogen (N) deposition rates (0,10,and 20 kg N ha-1 year-1 as (NH4)2SO4) on soil N2O and CH4 fluxes.The seasonal and diurnal variations of soil N2O and CH4 fluxes were determined using the static chamber-gas chromatography method during the two growing seasons of 2008 and 2009.Soil temperature,moisture and mineral N (NH4+-N and NO3--N) concentration were simultaneously measured.Results showed that low level of (NH4)2SO4 (10 kg N ha-1 year-1) did not significantly affect soil CH4 and N2O fluxes and other variables.High level of (NH4)2SO4 (20 kg N ha-1 year-1) significantly increased soil NO3--N concentration by 24.1％ to 35.6％,decreased soil CH4 uptake by an average of 20.1％,and significantly promoted soil N2O emission by an average of 98.2％.Soil N2O emission responded more strongly to the added N compared to CH4 uptake.However,soil CH4 fluxes were mainly driven by soil moisture,followed by soil NO3--N concentration.Soil N2O fluxes were mainly driven by soil temperature,followed by soil moisture.Soil inorganic N availability was a key integrator of soil CH4 uptake and N2O emission.These results suggest that the changes of availability of inorganic N induced by the increased N deposition in soil may affect the CH4 and N2O fluxes in the cold semi-arid meadow steppe over the short term.     

不同生物炭对中国亚热带地区湿地松生长、氮肥利用率、土壤N2O和CH4排放以及碳变化的影响

Intensive management of planted forests may result in soil degradation and decline in timber yield with successive rotations.Biochars may be beneficial for plant production,nutrient uptake and greenhouse gas mitigation.Biochar properties vary widely and are known to be highly dependent on feedstocks,but their effects on planted forest ecosystem are elusive.This study investigated the effects of chicken manure biochar,sawdust biochar and their feedstocks on 2-year-old Pinus elliottii growth,fertilizer N use efficiency (NUE),soil N2O and CH4 emissions,and C storage in an acidic forest soil in a subtropical area of China for one year.The soil was mixed with materials in a total of 8 treatments:non-amended control (CK);sawdust at 2.16 kg m-2 (SD);chicken manure at 1.26 kg m-2 (CM);sawdust biochar at 2.4 kg m-2 (SDB);chicken manure biochar at 2.4 kg m-2 (CMB);15N-fertilizer alone (10.23 atom％ 15N) (NF);sawdust biochar at 2.4 kg m-2 plus 15N-fertilizer (SDBN) and chicken manure biochar at 2.4 kg m-2 plus 15N-fertilizer (CMBN).Results showed that the CMB treatment increased P.elliottii net primary production (aboveground biomass plus litterfall) and annual net C fixation (ANCF) by about 180％ and 157％,respectively,while the the SDB treatment had little effect on P.elliottii growth.The 15N stable isotope labelling technique revealed that fertilizer NUE was 22.7％ in CK,25.5％ in the NF treatment,and 37.0％ in the CMB treatment.Chicken manure biochar significantly increased soil pH,total N,total P,total K,available P and available K.Only 2％ of the N in chicken manure biochar was available to the tree.The soil N2O emission and CH4 uptake showed no significant differences among the treatments.The apparent C losses from the SD and CM treatments were 35％ and 61％,respectively;while those from the CMB and SDB treatments were negligible.These demonstrated that it is crucial to consider biochar properties while evaluating their effects on plant growth and C sequestration.     

土壤呼吸对生物炭添加的短期响应：发酵后处理和无机氮的影响

The biodegradability of chars derived from pyrolysis and hydrothermal carbonisation (HTC) was studied in short-term dynamic incubation experiments under controlled conditions. Carbon dioxide C (CO$_{2}$) emissions from soil-char mixtures in combination with solid digestate or mineral nitrogen (N) fertiliser were measured in dynamic chambers for 10 d.~Compared to the original material (maize straw), pyrolysis and HTC chars showed significantly lower CO$_{2}$ emissions and slower decay dynamics; and compared to the soil control, HTC char increased soil respiration to a significant extent, while pyrolysis char did not. The addition of mineral N resulted in a delayed respiration dynamics for HTC char, while the addition of digestate resulted in an increase in the respired CO$_{2}$ for pyrolysis char and a decrease for HTC char. For the first time, a peculiar two-stage decay kinetics was observed for HTC char, indicating a highly inhomogeneous substrate consisting at least of two C pools.     

Yield and Performance and Soil Properties of Organically Fertilized Fodder Crops

The aim of this study was to evaluate the effects of experimental amendments on yields of Trifolium subterraneum L., Pisum arvense L., and Lolium multiflorum Lam., and on soil characteristics. A two-year research was carried out comparing anaerobic digestate (AD) and olive-pomace compost (OPC) with mineral fertilizer (Min), commercial organic-mineral fertilizer (Org-min), and unfertilized control (Cont). Anaerobic digestate and OPC were firstly analyzed for their chemical characteristics. The most important parameters were recorded and soil properties were investigated. Anaerobic digestate showed the highest dry weight for ryegrass, the best yield in pea, and good level of dry matter in clover. Good responses were achieved by OPC. Anaerobic digestate increased total soil organic carbon by 14.4, 8.1 and 7.6% than Min, Org-min and Cont, respectively. Olive-pomace compost increased the same parameter by 16.3, 10.0, and 9.5%. The findings indicated the possibility to substitute mineral fertilizers with organic ones without decreasing yields and support soil fertility.     

Soil Immobilization of Heavy Metal Using Soil Amendments in a Greenhouse Study

ABSTRACT

The application of soil amendments to immobilize heavy metals is a promising technology to meet the requirements for environmentally sound and cost-effective remediation. The present work was carried out to evaluate the effect of phosphogypsum (PG) used alone and in combination with compost (CP) at a mix ratio of 1:1 wet weight ratio (PG+CP) at 10 and 20 g dry weight kg^?1 dry soil, on heavy metal immobilization in contaminated soil, and on canola growth (Brassica napus). The results were then compared with untreated soil (control). The results revealed that the Pb, Cd, and Zn uptake of canola plants was reduced by the application of PG alone and when it was mixed with CP. At an application rate of 10 g dry weight kg^?1 dry soil of (PG+CP), the dry weight of canola plants increased by 66.8%, which was increased in comparison on its weight in the untreated soil (control). The addition of PG alone resulted in more pronounced immobilization of heavy metals as compared to PG mixed with CP. Plant growth was improved with CP addition but heavy metals immobilization was greatest in PG alone treatments. Results suggest that PG may be useful for the immobilization of heavy metals in contaminated soils.     

土壤碳氮对多年生能源草、覆盖作物和氮施肥的响应

Cover crop and nitrogen(N) fertilization may maintain soil organic matter under bioenergy perennial grass where removal of aboveground biomass for feedstock to produce cellulosic ethanol can reduce soil quality. We evaluated the effects of cover crops and N fertilization rates on soil organic carbon(C)(SOC), total N(STN), ammonium N(NH_4-N), and nitrate N(NO_3-N) contents at the0–5, 5–15, and 15–30 cm depths under perennial bioenergy grass from 2010 to 2014 in the southeastern USA. Treatments included unbalanced combinations of perennial bioenergy grass, energy cane(Saccharum spontaneum L.) or elephant grass(Pennisetum purpureum Schumach.), cover crop, crimson clover(Trifolium incarnatum L.), and N fertilization rates(0, 100, and 200 kg N ha~(-1)). Cover crop biomass and C and N contents were greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1) than in the treatment of energy cane and elephant grass. The SOC and STN contents at 0–5 and 5–15 cm were 9%–20% greater in the treatments of elephant grass with cover crop and with or without 100 kg N ha~(-1)than in most of the other treatments. The soil NO_3-N content at 0–5 cm was 31%–45% greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1)than in most of the other treatments.The SOC sequestration increased from 0.1 to 1.0 Mg C ha~(-1)year~(-1)and the STN sequestration from 0.03 to 0.11 Mg N ha~(-1)year~(-1)from 2010 to 2014 for various treatments and depths. In contrast, the soil NH_4-N and NO_3-N contents varied among treatments,depths, and years. Soil C and N storages can be enriched and residual NO_3-N content can be reduced by using elephant grass with cover crop and with or without N fertilization at a moderate rate.     

玉米铬毒性研究：氧化损伤、渗透调节物质积累、抗氧化防御以及铬的吸收

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium(Cr) stress levels, i.e., 0, 30, 6090, 120, and 150 μmol L-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation o reactive oxygen species(ROS), and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots leaves stem seeds in both genotypes. The increased Cr toxicity resulted in higher free proline soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide(H2O2) and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.     

深色有隔内生真菌柱孢顶囊壳对玉米幼苗生长、光合作用及耐铅能力的影响

Dark septate endophytic (DSE) fungi are ubiquitous and cosmopolitan,and occur widely in association with plants in heavy metal stress environment.However,little is known about the effect of inoculation with DSE fungi on the host plant under heavy metal stress.In this study,Gaeumannomyces cylindrosporus,which was isolated from Pb-Zn mine tailings in China and had been proven to have high Pb tolerance,was inoculated onto the roots of maize (Zea mays L.) seedlings to study the effect of DSE on plant growth,photosynthesis,and the translocation and accumulation of Pb in plant under stress of different Pb concentrations.The growth indicators (height,basal diameter,root length,and biomass) of maize were detected.Chlorophyll content,photosynthetic characteristics (net photosynthetic rate,transpiration rate,stomatal conductance,and intercellular CO2 concentration),and chlorophyll fluorescence parameters in leaves of the inoculated and non-inoculated maize were also determined.Inoculation with G.cylindrosporus significantly increased height,basal diameter,root length,and biomass of maize seedlings under Pb stress.Colonization of G.cylindrosporus improved the efficiency of photosynthesis and altered the translocation and accumulation of Pb in the plants.Although inoculation with G.cylindrosporus increased Pb accumulation in host plants in comparison to non-inoculated plants,the translocation factor of Pb in plant body was significantly decreased.The results indicated that Pb was accumulated mainly in the root system of maize and the phytotoxicity of Pb to the aerial part of the plant was alleviated.The improvement of efficiency of photosynthesis and the decrease of translocation factor of Pb,caused by DSE fungal colonization,were efficient strategies to improve Pb tolerance of host plants.     

Contribution of nitrification happened in rhizospheric soil growing with different rice cultivars to N nutrition

A rhizobox with three compartments and soil slicing followed by quick freezing were used to study the spatiotemporal variations of nitrification of rhizospheric soil of Yangdao 6 (Indica) and Nongken 57 (Japonica). The results obtained revealed that ammonium () was the main N form in flooded paddy soil. A concentration gradient for was observed with the lowest concentration nearer to the root zone and the concentrations increased with increasing distance from the root zone. No concentration gradient was observed for nitrate (). The nitrification activities of both rice cultivars increased with the development of the incubation time. The nitrification activities were maximal in rhizospheric soil, followed by those in bulk soil and in the root zone. In the rhizosphere, nitrification activities decreased with increasing distance from the root zone. The maximal nitrification activity measured at 44, 51, and 58 days after sowing of Yangdao 6 and Nongken 57 rice cultivars was at a distance of 6 and 2 mm away from the root zone, respectively, and they were 0.88 and 0.73 mg kg⁻¹ h⁻¹, respectively. In this experiment, the nitrification activities were significantly and positively correlated with the ammonia-oxidizing bacteria (AOB) abundance (r=0.86, p<0.01). The nitrification activity, concentration, AOB abundance, dry matter and N accumulation and leaf reductase activity associated with Indica were always higher than those with Japonica. Therefore, nitrification in rhizosphere had more important significance for N nutrition, especially for the Indica rice cultivars.     

Effect of sewage sludge on nodulation and N2−fixation in alfalfa grown on calcareous loamy soils

The influence of different rates of sludge applications to calcareous loamy soils of Saudi Arabia, on nodulation and symbiotic N₂?fixation in alfalfa plants (Medicago sativa L.) was studied in a pot experiment. The effect of heavy metals accumulation in soil due to continuous irrigation of the test soil with sewage water was also investigated. Application of up to 80 g sludge per pot enhanced nodulation, nitrogenase activity, dry matter yield and N-contents of alfalfa plants growing in loamy soils either previously irrigated with sewage water or well water. However, sludge applied at the rate of 160–200 g pot^?1 inhibited the nodulation, N accumulation and dry matter yield of alfalfa. The response of alfalfa to sludge was dependent on the rhizobial strain used. Our results also showed that accumulation of heavy metals due to continuous irrigation of a calcareous sandy loam soil with sewage water, for more than 10 years, didn't inhibit N₂?fixation in alfalfa plants, but enhanced it. Microelements in alfalfa plants increased with increase in the rate of sludge application. Although high rates of sludge application affected nodulation and N₂?fixation of alfalfa, dry matter and the nitrogen contents of the plants were not highly affected. Therefore, the inhibitory effect of high rates of sludge was most probably due to the toxic effect of heavy metals on the microsymbiont rather than on the plants.