The harmless treatment of livestock and poultry reduces the risk of water and soil pollution caused by untreated discard of sick and dead livestock.Chemical fertilizer increases crop yield,while its over-application w...The harmless treatment of livestock and poultry reduces the risk of water and soil pollution caused by untreated discard of sick and dead livestock.Chemical fertilizer increases crop yield,while its over-application will lead to serious problems such as agricultural non-point source pollution as well as land acidification and soil compaction.It is of great significance to explore the utilization potential of bio-organic matter originating from harmless treatment of livestock to improve the soil environment and enhance agricultural productivity.This study investigated the effects of different application rates of bio-organic matter(0,1285,1928,2571 kg/hm^(2))and biochar addition(0,10000 kg/hm^(2))on soil properties and crop yield under 20%reduction of chemical nitrogen fertilizer.The results indicated that the application of bio-organic matter combined with biochar improved soil physical structure under fertilizer reduction by decreasing soil bulk density and increasing soil porosity and soil aggregate stability.Compared to that under CK,the soil bulk density was reduced by 1.42%-6.38%,and the soil porosity was increased by 1.17%-7.05%.Compared to conventional fertilization,applying bio-organic matter(1928 kg/hm^(2))ensured sufficient soil nutrients for crop growth under 20%of fertilizer reduction.The soil fertility was further boosted by the addition of biochar.The alkaline nitrogen content peaked under BM3 with 42.08 mg/kg,and the total nitrogen content and soil organic matter content reached their peak values under NM4 treatment,which were 0.97 g/kg and 21.23 g/kg,respectively.The higher the amount of bio-organic matter applied,the higher the grain yield and crop water productivity.The yield gained with bio-organic matter application alone at the rate of 2571 kg/hm^(2)under fertilizer reduction(NM4)was 7504 kg/hm^(2),which can reach equal yield level with CK,while medium to high addition of bio-organic matter combining biochar(BM3 and BM4 treatments)produced higher grain yield than that under CK.The correlation analysis showed significant positive correlations between total nitrogen and maize yield and between soil organic matter and maize yield.Overall,under 20%fertilizer reduction,applying bio-organic matter at the rate of 1928 kg/hm^(2)and combining biochar at the rate of 10000 kg/hm^(2)would be an economical plan to enhance soil physicochemical properties and ensure stable maize yield,and would also supply a scientific way to reuse bio-organic matter originating from harmless treatment of livestock carcasses.展开更多
Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Pro...Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Province. The results showed that among the grade-one nutritive elements in soil, organic matter, nitrogen and phosphorus were relatively deficient while potassium was rich. Meanwhile, as the grade-two nutritive elements, calcium oxide and magnesium oxide were relatively short and sulfur’s content was abundant. About the other beneficial and trace nutri-tive elements, iron oxide, manganese, molybdenum and boron were deficient, but the content of chlorine was high, hardly lack. The main barriers to improving land productivity were soil salinization and soil heavy metal contamination. The values of soil integrated fertility index that most of the soil in the study area is middle-lower fertilized. Specifical y, the low fertility area and lower fertility area are 6 1604 and 1 244 km2 respectively, occupying about 97.43% and 1.97% of the total area. The moderate fertility soil has an area of 172 km2, occupying about 0.27% of the total area. The higher fertility soil covers an area of 128 km2, while the high fertility area of only 76 km2. This article proposed scientific fertilization, elimination of soil obsta-cle, remediation of heavy-metal-contaminated soil and other effective measures to improve land productivity according to the basic investigation results, which provides a good technological support for the planning and development of good-quality and high-benefit agriculture.展开更多
In order to more efficiently utilize gypsum to improve meadow alkali soil slightly salinized by soda and sulfate chloride, a total of 27 treatments were de- signed from the perspectives of field capacity, alkalinity, ...In order to more efficiently utilize gypsum to improve meadow alkali soil slightly salinized by soda and sulfate chloride, a total of 27 treatments were de- signed from the perspectives of field capacity, alkalinity, alkaline salt content, optimal irrigation, gypsum conversion, gypsum and soil treatment and improvement depth. The ions on the obtained filtrate were analyzed in terms of salts. The improving ef- ficiency of gypsum for meadow alkali soil was analyzed through comparing the con- tents of soluble salts in pre-improvement and post-improvement soil by reasoning and calculation. The results showed that, （1） the dissolved amount and conversion amount of gypsum were increased, and the soil alkalinity was decreased corre- spondingly with the increased irrigation amount. However, after reaching a certain extent, the linear relationships became unobvious gradually. Therefore, the irrigation amount should be arranged reasonably for different treatment. （2） Compared with those at low temperature, the dissolved amount of gypsum at high temperature was increased by 1.47-1.50 times, the release amount of exchangeable sodium was in- creased by 2.98-4.70 times, and the release amount of exchangeable magnesium was increased by 2.07-2.90 times. In overall, the improving efficiency of gypsum in summer was better. However, gypsum had two shortcomings in summer. First, a large amount of gypsum leaked away. Second, a large amount of exchangeable magnesium, along with exchangeable sodium, was substituted by gypsum. （3） Compared with the other two treatments, treatment B （mixing gypsum and top 20- cm soil） showed the best improving efficiency, and it was characterized by stepwise dealkalization from top to down. In addition, mixing gypsum and topsoil is more practical in the production.展开更多
Soil improvement is one of the most important issues in geotechnical engineering practice.The wide application of traditional improvement techniques(cement/chemical materials)are limited due to damage ecological en-vi...Soil improvement is one of the most important issues in geotechnical engineering practice.The wide application of traditional improvement techniques(cement/chemical materials)are limited due to damage ecological en-vironment and intensify carbon emissions.However,the use of microbially induced calcium carbonate pre-cipitation(MICP)to obtain bio-cement is a novel technique with the potential to induce soil stability,providing a low-carbon,environment-friendly,and sustainable integrated solution for some geotechnical engineering pro-blems in the environment.This paper presents a comprehensive review of the latest progress in soil improvement based on the MICP strategy.It systematically summarizes and overviews the mineralization mechanism,influ-encing factors,improved methods,engineering characteristics,and current field application status of the MICP.Additionally,it also explores the limitations and correspondingly proposes prospective applications via the MICP approach for soil improvement.This review indicates that the utilization of different environmental calcium-based wastes in MICP and combination of materials and MICP are conducive to meeting engineering and market demand.Furthermore,we recommend and encourage global collaborative study and practice with a view to commercializing MICP technique in the future.The current review purports to provide insights for engineers and interdisciplinary researchers,and guidance for future engineering applications.展开更多
[Objectives]Farmland ginseng cultivation,as a sustainable alternative to traditional forest-clearing ginseng planting,requires systematic evaluation of soil optimization strategies.This study aimed to quantify the lin...[Objectives]Farmland ginseng cultivation,as a sustainable alternative to traditional forest-clearing ginseng planting,requires systematic evaluation of soil optimization strategies.This study aimed to quantify the linkage between soil improvement outcomes and ginseng(Panax ginseng)yield across five regions in Yanbian Korean Autonomous Prefecture.[Methods]Soil improvement trials were conducted using farmland soils,with forest soils as the baseline.Soil nutrient contents were measured via soil agrochemical analysis method using a continuous flow analyzer.Statistical approaches,including significance tests,correlation analysis,and regression analysis,were applied to identify key factors influencing yield.[Results]Ginseng yield exhibited a significant positive correlation with organic matter content and available phosphorus,but a negative correlation with electrical conductivity,ammonium nitrogen,and available potassium.Wangqing and Liucai regions achieved post-improvement yields equivalent to 94%and 88%of forest soil yields,respectively,demonstrating the highest soil similarity to forest ecosystems.[Conclusions]Region-specific soil improvement protocols in Wangqing and Liucai show high replicability and efficacy.These strategies can serve as benchmarks for sustainable farmland ginseng cultivation,minimizing ecological disruption while maintaining productivity.展开更多
Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ul...Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.展开更多
Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper...Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper proposes the selection of a granular SFL(GSFL)with a relatively large particle size,but with its chemical properties retained,to replace the conventional powdered SFL(PSFL).Among the processes of water-induced erosion failure of earthen structures,disintegration is commonly deemed the primary cause.Therefore,the disintegration characteristics of both PSFL-and GSFL-modified soils with 0%,5%,7%,10%,and 12%dosages were tested under dry-wet conditions.Moreover,several physicochemical properties,including the particle size distribution,bound water content,pH value,cation exchange capacity,functional groups,and microstructure,were explored.The results revealed that the water stability of the GSFL-modified soils was greater than that of the PSFL-modified soils.All of the PSFL-modified soils and natural soil completely disintegrated at the first immersion stage,whereas the GSFL-modified soils resisted 7 dry-wet cycles,notably at the 10%dosage.Microscopic analysis revealed that the SFL particle size affected mainly the cementation strength and microstructural homogeneity.Both the GSFL and PSFL particles strengthened the intergranular cementation through ion exchange,electrostatic interactions,and reinforcement effects.However,the PSFL preferentially filled the intragranular pores,causing a nonuniform microstructural arrangement and ineffectively enhancing the disintegration resistance of the saline soil.This preliminary study suggests that the particle size of a soil modifier may affect certain properties of the modified soil,necessitating future focused research.展开更多
1.The key to achieving China’s dual carbon goals As pointed out in the CO_(2) Emissions in 2023 report released by the International Energy Agency,global carbon dioxide(CO_(2))emis-sions reached 37.4 billion tonnes i...1.The key to achieving China’s dual carbon goals As pointed out in the CO_(2) Emissions in 2023 report released by the International Energy Agency,global carbon dioxide(CO_(2))emis-sions reached 37.4 billion tonnes in 2023[1],setting a new record high.The increase in CO_(2) emissions has exacerbated global warm-ing and led to a series of global climate problems.China is a major emitter of CO_(2).展开更多
This study was conducted to study the feasibility of biochar in soil im- provement and tobacco quality. The black soil in NinganCountry of Mudanjiang was used as the material in this study, and the effects of biochar ...This study was conducted to study the feasibility of biochar in soil im- provement and tobacco quality. The black soil in NinganCountry of Mudanjiang was used as the material in this study, and the effects of biochar on tobacco-planting soil C/N, soil microorganisms, the development of tobacco, and chemical compo- nents and neutral aroma components in flue-cured tobacco werestudied. The results showed that the application of biochar at a rate of 1 800 kg/hm2 could increase soil C/N by 31.79%, and the quantity of actinomycetes in the soil was 3.8 times as much as that in control. The growth wasobviously better after biochar application, plant height and effective leaf number were significantly higher than those ofcontrol, but total sugar and nicotine were not significantly different. The application of biochar at a rate of 1 200 kg/hm2 increased the potassium content by 11%, the application of biochar at a rate of 2 400 kg/hm2 improved total sugar content by 5.40%, and the application of biochar at a rate of 1 800 kg/hm2 made the tobacco solanone content 1.97 times as that of control. Comprehensive studies showed that the application of biochar 1 200-1 800 kg/hm2 could improvesoilenvironment, and promote tobacco growth and quality.展开更多
The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of grani...The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of granite residual soil in certain areas. Research on the mechanical properties and controlling mechanisms of disintegration has become a hot issue in practical engineering. In this paper, the disintegration characteristics of improved granite residual soil are studied by using a wet and dry cycle disintegration instrument, and the improvement mechanism is analyzed. The results show that the disintegration amounts and disintegration ratios of soil samples treated with different curing agents are obviously different. The disintegration process of improved granite residual soil can be roughly divided into 5 stages:the forcible water intrusion stage, microcrack and fissure development stage, curing and strengthening stage, stable stage, and sudden disintegration stage. The disintegration of granite residual soil is caused by the weakening of the cementation between soil particles under the action of water. When the disintegration force is greater than the anti-disintegration force of soil, the soil will disintegrate. Cement and lime mainly rely on ion exchange agglomeration, the inclusion effect of curing agents on soil particles, the hard coagulation reaction and carbonation to strengthen granite residual soil. Kaolinite mainly depends on the reversibility of its own cementation to improve and strengthen granite residual soil. The reversibility of kaolinite cementation is verified by investigating pure kaolinite with a tensile, soaking, drying and tensile test cycle. Research on the disintegration characteristics and disintegration mechanism of improved granite residual soil is of certain reference value for soil modification.展开更多
The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that m...The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1) of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.展开更多
A shake-table experiment on pile foundations in liquefi able soils composed of liquefi able sand and overlying soft clay is studied. A three-dimensional(3D) effective stress fi nite element(FE) analysis is employed to...A shake-table experiment on pile foundations in liquefi able soils composed of liquefi able sand and overlying soft clay is studied. A three-dimensional(3D) effective stress fi nite element(FE) analysis is employed to simulate the experiment. A recently developed multi-surface elasto-plastic constitutive model and a fully coupled dynamic inelastic FE formulation(u-p) are used to model the liquefaction behavior of the sand. The soil domains are discretized using a solid-fl uid fully coupled(u-p) 20-8 noded brick element. The pile is simulated using beam-column elements. Upon careful calibration, very good agreement is obtained between the computed and the measured dynamic behavior of the ground and the pile. A parametric analysis is also conducted on the model to investigate the effect of pile-pinning, pile diameter, pile stiffness, ground inclination angle, superstructure mass and pile head restraints on the ground improvement. It is found that the pile foundation has a noticeable pinning effect that reduces the lateral soil displacement. It is observed that a larger pile diameter and fi xed pile head restraints contribute to decreasing the lateral pile deformation; however, a higher ground inclination angle tends to increase the lateral pile head displacements and pile stiffness, and superstructure mass seems to effectively infl uence the lateral pile displacements.展开更多
Glomalin-related soil protein(GRSP)sequesters large amounts of carbon and plays important roles in maintaining terrestrial soil ecosystem functions and ecological restoration;however,little is known about GRSP variati...Glomalin-related soil protein(GRSP)sequesters large amounts of carbon and plays important roles in maintaining terrestrial soil ecosystem functions and ecological restoration;however,little is known about GRSP variation in 1-m soil profiles and its association with stand characteristics,soil properties,and climatic conditions,hindering GRSP-related degraded soil improvement and GRSP evaluation.In this study,we sampled soils from 1-m profiles from poplar(Populus spp.)shelterbelts in Northeast China.GRSP contents were 1.8–2.0 times higher in the upper 40 cm soil layers than at 40–100 cm.GRSP-related soil organic carbon(SOC)sequestration in deeper soil layers was*1.2 times higher than in surface layers.The amounts of GRSP-related nutrients were similar throughout the soil profile.A redundancy analysis showed that in both surface and deeper layers,soil properties(pH,electrical conductivity,water,SOC,and soil nutrients)explained the majority of the GRSP variation(59.5–84.2%);the second-most-important factor in GRSP regulation was climatic conditions(temperature,precipitation,and altitude),while specific shelterbelt characteristics had negligible effects(<5%).Soil depth and climate indirectly affected GRSP features via soil properties,as manifested by structural equation model analysis.Our findings demonstrate that GRSP is important for carbon storage in deep soils,regardless of shelterbelt characteristics.Future glomalin assessments should consider these vertical patterns and possible regulating mechanisms that are related to soil properties and climatic changes.展开更多
The concept of using biological process in soil improvement which is known as bio-mediated soil improvement technique has shown greater potential in geotechnical engineering applications in terms of performance and en...The concept of using biological process in soil improvement which is known as bio-mediated soil improvement technique has shown greater potential in geotechnical engineering applications in terms of performance and environmental sustainability. This paper presents a review on the soil microorganisms responsible for this process, and factors that affect their metabolic activities and geometric compatibility with the soil particle sizes. Two mechanisms of biomineralization, i.e. biologically controlled and biologically induced mineralization, were also discussed. Environmental and other factors that may be encountered in situ during microbially induced calcite precipitation （MICP） and their influences on the process were identified and presented. Improvements in the engineering properties of soil such as strength/stiffness and permeability as evaluated in some studies were explored. Potential applications of the process in geotechnical engineering and the challenges of field application of the process were identified.展开更多
Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added durin...Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added during chemical stabilization could improve the engineering properties of treated soils.Stabilizers utilized have to satisfy noticeable performance,durability,low price,and can be easily implemented.Since cement kiln dust(CKD) is industrial by-product,it would be a noble task if this waste material could be utilized for stabilization of sabkha soil.This study investigates the feasibility of utilizing CKD for improving the properties of sabkha soil.Soil samples are prepared with 2% cement and 10%,20% or 30% CKD and are tested to determine their unconfined compressive strength(UCS),soaked California bearing ratio(CBR) and durability.Mechanism of stabilization is studied utilizing advanced techniques,such as the scanning electron microscope(SEM),energy dispersive X-ray analysis(EDX),backscattered electron image(BEI) and X-ray diffraction analysis(XRD).It is noted that the sabkha soil mixed with 2% cement and 30% CKD could be used as a sub-base material in rigid pavements.The incorporation of CKD leads to technical and economic benefits.展开更多
The bio-briquette technique which mixes coal, biomass and sulfur fixation agent and bio-briquettes under 3—5 t/cm 2 line pressure has aroused people's attention in view of controlling the air pollution and the ...The bio-briquette technique which mixes coal, biomass and sulfur fixation agent and bio-briquettes under 3—5 t/cm 2 line pressure has aroused people's attention in view of controlling the air pollution and the acid rain. In this paper, the physicochemical properties of bio-briquette and its ash were investigated. And the acid soil was improved by the bio-briquette combustion ash, which contained nutritive substances such as P, N, K and had the acid-neutralizing capacity(ANC). The pH, EC, effective nutrient elements(Ca, Mg, K, P and N), heavy metal elements(Al, Cu, Cd, Cr, Zn and Mn) and acid-neutralizing capacity change of ash-added soils within the range of 0—10%, were also studied. Specially, when 5% bio-briquette combustion ash was added to the tested soil, the content of the effective elements such as Ca, Mg and K rose by 100 times, 7 times and twice, respectively. The total nitrogen also increased by about twice. The results showed the oxyanions such as that of Al, Cu, Cd, Cr, Zn and Mn were not potentially dangerous, because they were about the same as the averages of them in Chinese soil. It is shown that the ANC became stronger, though the ANC hardly increases in the ash-added soil. On the basis of the evaluation indices, it is concluded that the best mixture ratio is to add 2.5%—8% of the bio-briquette combustion ash to the tested soil.展开更多
A detailed research in soil improving measure was conducted during the process of plants that were cultivated in Tianjin saline and alkaline area. The results showed that the commonly used measures could improve the s...A detailed research in soil improving measure was conducted during the process of plants that were cultivated in Tianjin saline and alkaline area. The results showed that the commonly used measures could improve the soil, and also we got some useful advices and suggestions for plants cultivating in Tianiin saline and alkaline areas.展开更多
The weak intercalated soils in redbed soft rocks of Badong formation have obvious creep characters. In order to predict the unsaturated creep behaviors of weak intercalated soils, an unsaturated creep model was establ...The weak intercalated soils in redbed soft rocks of Badong formation have obvious creep characters. In order to predict the unsaturated creep behaviors of weak intercalated soils, an unsaturated creep model was established based on the unsaturated creep tests of weak intercalated soils by using GDS triaxial apparatus. The results show that the creep behaviors of intercalated soils are apparent and significantly affected by matric suction. Based on this, an empirical Mesri creep model for intercalated soils under varying matric suctions was built. The fitting results show that the parameters Ed and m of this model are in good power relations with matric suction s and stress level Dr, respectively. An improved Mesri creep model was established involving stress-matric suction-strain-time, which is more precise than the Mesri creep model in predicting the unsaturated creep behaviors of weak intercalated soils.展开更多
The use of electro-osmotic chemical is an effective method to improve the clayey soil foundation.Various boundary conditions can be adopted in this method.In this work,two electrode–clay contacts,three solution condi...The use of electro-osmotic chemical is an effective method to improve the clayey soil foundation.Various boundary conditions can be adopted in this method.In this work,two electrode–clay contacts,three solution conditioners,and four anode solution supply times were used for clayey soil improvement.Based on the experimental data,electro-osmotic consolidation theory,and transport of ion theory,it is found that the electro-osmotic chemical effect of the separation of electrode–clay(E_S)is more beneficial for the transport of Ca^(2+),production of cementing material,and reduction of water content than that of electrode–clay(E_C)joining;through electrode–clay contact separation,the anode solution conditioner(NaPO3)6(E_SHMP)delayed the cementing reaction and then increased the transport of Ca^(2+)near the cathode,which increased the amount of cementing material and the electro-osmotic chemical effect;and when the anode conditioner(NaPO3)6 was used,two days of anode solution supply followed by three days cut off from the anode solution led to the highest undrained shear strength increase after the application of electro-osmotic chemical,which resolved the uneven electro-osmotic chemical effect in the E_SHMP.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51609209)the Key Laboratory Program of the Shangqiu Station of National Field Agro-ecosystem(Grant No.SQZ-2023-01).
文摘The harmless treatment of livestock and poultry reduces the risk of water and soil pollution caused by untreated discard of sick and dead livestock.Chemical fertilizer increases crop yield,while its over-application will lead to serious problems such as agricultural non-point source pollution as well as land acidification and soil compaction.It is of great significance to explore the utilization potential of bio-organic matter originating from harmless treatment of livestock to improve the soil environment and enhance agricultural productivity.This study investigated the effects of different application rates of bio-organic matter(0,1285,1928,2571 kg/hm^(2))and biochar addition(0,10000 kg/hm^(2))on soil properties and crop yield under 20%reduction of chemical nitrogen fertilizer.The results indicated that the application of bio-organic matter combined with biochar improved soil physical structure under fertilizer reduction by decreasing soil bulk density and increasing soil porosity and soil aggregate stability.Compared to that under CK,the soil bulk density was reduced by 1.42%-6.38%,and the soil porosity was increased by 1.17%-7.05%.Compared to conventional fertilization,applying bio-organic matter(1928 kg/hm^(2))ensured sufficient soil nutrients for crop growth under 20%of fertilizer reduction.The soil fertility was further boosted by the addition of biochar.The alkaline nitrogen content peaked under BM3 with 42.08 mg/kg,and the total nitrogen content and soil organic matter content reached their peak values under NM4 treatment,which were 0.97 g/kg and 21.23 g/kg,respectively.The higher the amount of bio-organic matter applied,the higher the grain yield and crop water productivity.The yield gained with bio-organic matter application alone at the rate of 2571 kg/hm^(2)under fertilizer reduction(NM4)was 7504 kg/hm^(2),which can reach equal yield level with CK,while medium to high addition of bio-organic matter combining biochar(BM3 and BM4 treatments)produced higher grain yield than that under CK.The correlation analysis showed significant positive correlations between total nitrogen and maize yield and between soil organic matter and maize yield.Overall,under 20%fertilizer reduction,applying bio-organic matter at the rate of 1928 kg/hm^(2)and combining biochar at the rate of 10000 kg/hm^(2)would be an economical plan to enhance soil physicochemical properties and ensure stable maize yield,and would also supply a scientific way to reuse bio-organic matter originating from harmless treatment of livestock carcasses.
基金Supported by Multi-goal Geochemical Survey in Laoling-Hekou Regions,Shandong Province of National Soil Survey and Pollution Prevention(GZTR20060104)~~
文摘Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Province. The results showed that among the grade-one nutritive elements in soil, organic matter, nitrogen and phosphorus were relatively deficient while potassium was rich. Meanwhile, as the grade-two nutritive elements, calcium oxide and magnesium oxide were relatively short and sulfur’s content was abundant. About the other beneficial and trace nutri-tive elements, iron oxide, manganese, molybdenum and boron were deficient, but the content of chlorine was high, hardly lack. The main barriers to improving land productivity were soil salinization and soil heavy metal contamination. The values of soil integrated fertility index that most of the soil in the study area is middle-lower fertilized. Specifical y, the low fertility area and lower fertility area are 6 1604 and 1 244 km2 respectively, occupying about 97.43% and 1.97% of the total area. The moderate fertility soil has an area of 172 km2, occupying about 0.27% of the total area. The higher fertility soil covers an area of 128 km2, while the high fertility area of only 76 km2. This article proposed scientific fertilization, elimination of soil obsta-cle, remediation of heavy-metal-contaminated soil and other effective measures to improve land productivity according to the basic investigation results, which provides a good technological support for the planning and development of good-quality and high-benefit agriculture.
基金Supported by National Natural Science Foundation of China(41401559)Project of Hubei Provincial Science and Technology Department(2014CFB558)Project of Hubei Provincial Department of Education(D20141001)~~
文摘In order to more efficiently utilize gypsum to improve meadow alkali soil slightly salinized by soda and sulfate chloride, a total of 27 treatments were de- signed from the perspectives of field capacity, alkalinity, alkaline salt content, optimal irrigation, gypsum conversion, gypsum and soil treatment and improvement depth. The ions on the obtained filtrate were analyzed in terms of salts. The improving ef- ficiency of gypsum for meadow alkali soil was analyzed through comparing the con- tents of soluble salts in pre-improvement and post-improvement soil by reasoning and calculation. The results showed that, （1） the dissolved amount and conversion amount of gypsum were increased, and the soil alkalinity was decreased corre- spondingly with the increased irrigation amount. However, after reaching a certain extent, the linear relationships became unobvious gradually. Therefore, the irrigation amount should be arranged reasonably for different treatment. （2） Compared with those at low temperature, the dissolved amount of gypsum at high temperature was increased by 1.47-1.50 times, the release amount of exchangeable sodium was in- creased by 2.98-4.70 times, and the release amount of exchangeable magnesium was increased by 2.07-2.90 times. In overall, the improving efficiency of gypsum in summer was better. However, gypsum had two shortcomings in summer. First, a large amount of gypsum leaked away. Second, a large amount of exchangeable magnesium, along with exchangeable sodium, was substituted by gypsum. （3） Compared with the other two treatments, treatment B （mixing gypsum and top 20- cm soil） showed the best improving efficiency, and it was characterized by stepwise dealkalization from top to down. In addition, mixing gypsum and topsoil is more practical in the production.
基金funded by the National Natural Science Foundation of China(No.41962016)the Natural Science Foundation of NingXia(Nos.2023AAC02023,2023A1218,and 2021AAC02006).
文摘Soil improvement is one of the most important issues in geotechnical engineering practice.The wide application of traditional improvement techniques(cement/chemical materials)are limited due to damage ecological en-vironment and intensify carbon emissions.However,the use of microbially induced calcium carbonate pre-cipitation(MICP)to obtain bio-cement is a novel technique with the potential to induce soil stability,providing a low-carbon,environment-friendly,and sustainable integrated solution for some geotechnical engineering pro-blems in the environment.This paper presents a comprehensive review of the latest progress in soil improvement based on the MICP strategy.It systematically summarizes and overviews the mineralization mechanism,influ-encing factors,improved methods,engineering characteristics,and current field application status of the MICP.Additionally,it also explores the limitations and correspondingly proposes prospective applications via the MICP approach for soil improvement.This review indicates that the utilization of different environmental calcium-based wastes in MICP and combination of materials and MICP are conducive to meeting engineering and market demand.Furthermore,we recommend and encourage global collaborative study and practice with a view to commercializing MICP technique in the future.The current review purports to provide insights for engineers and interdisciplinary researchers,and guidance for future engineering applications.
基金Supported by National Natural Science Foundation Cultivation Project of Lishui University(036/2024)Municipal-Level Project:Pathways for Establishing Low-carbon Pilot Counties(FGLS202210).
文摘[Objectives]Farmland ginseng cultivation,as a sustainable alternative to traditional forest-clearing ginseng planting,requires systematic evaluation of soil optimization strategies.This study aimed to quantify the linkage between soil improvement outcomes and ginseng(Panax ginseng)yield across five regions in Yanbian Korean Autonomous Prefecture.[Methods]Soil improvement trials were conducted using farmland soils,with forest soils as the baseline.Soil nutrient contents were measured via soil agrochemical analysis method using a continuous flow analyzer.Statistical approaches,including significance tests,correlation analysis,and regression analysis,were applied to identify key factors influencing yield.[Results]Ginseng yield exhibited a significant positive correlation with organic matter content and available phosphorus,but a negative correlation with electrical conductivity,ammonium nitrogen,and available potassium.Wangqing and Liucai regions achieved post-improvement yields equivalent to 94%and 88%of forest soil yields,respectively,demonstrating the highest soil similarity to forest ecosystems.[Conclusions]Region-specific soil improvement protocols in Wangqing and Liucai show high replicability and efficacy.These strategies can serve as benchmarks for sustainable farmland ginseng cultivation,minimizing ecological disruption while maintaining productivity.
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.52108307 and 52178319)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05020).
文摘Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.
基金funded by the National Natural Science Foundation of China(Grant Nos.42330708 and 42302329).
文摘Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper proposes the selection of a granular SFL(GSFL)with a relatively large particle size,but with its chemical properties retained,to replace the conventional powdered SFL(PSFL).Among the processes of water-induced erosion failure of earthen structures,disintegration is commonly deemed the primary cause.Therefore,the disintegration characteristics of both PSFL-and GSFL-modified soils with 0%,5%,7%,10%,and 12%dosages were tested under dry-wet conditions.Moreover,several physicochemical properties,including the particle size distribution,bound water content,pH value,cation exchange capacity,functional groups,and microstructure,were explored.The results revealed that the water stability of the GSFL-modified soils was greater than that of the PSFL-modified soils.All of the PSFL-modified soils and natural soil completely disintegrated at the first immersion stage,whereas the GSFL-modified soils resisted 7 dry-wet cycles,notably at the 10%dosage.Microscopic analysis revealed that the SFL particle size affected mainly the cementation strength and microstructural homogeneity.Both the GSFL and PSFL particles strengthened the intergranular cementation through ion exchange,electrostatic interactions,and reinforcement effects.However,the PSFL preferentially filled the intragranular pores,causing a nonuniform microstructural arrangement and ineffectively enhancing the disintegration resistance of the saline soil.This preliminary study suggests that the particle size of a soil modifier may affect certain properties of the modified soil,necessitating future focused research.
基金supported by the National Key Research and Development Program of China(2022YFC3901103)the National Natural Science Foundation of China(22288102)the Science and Technology Plan Project of the Xinjiang Production and Con-struction Crops(XPCC)(2023AB017-01).
文摘1.The key to achieving China’s dual carbon goals As pointed out in the CO_(2) Emissions in 2023 report released by the International Energy Agency,global carbon dioxide(CO_(2))emis-sions reached 37.4 billion tonnes in 2023[1],setting a new record high.The increase in CO_(2) emissions has exacerbated global warm-ing and led to a series of global climate problems.China is a major emitter of CO_(2).
基金Supported by Scientific and Technological Development Project of Tobacco Industry in Helongjiang Province(HYK[2015]59)~~
文摘This study was conducted to study the feasibility of biochar in soil im- provement and tobacco quality. The black soil in NinganCountry of Mudanjiang was used as the material in this study, and the effects of biochar on tobacco-planting soil C/N, soil microorganisms, the development of tobacco, and chemical compo- nents and neutral aroma components in flue-cured tobacco werestudied. The results showed that the application of biochar at a rate of 1 800 kg/hm2 could increase soil C/N by 31.79%, and the quantity of actinomycetes in the soil was 3.8 times as much as that in control. The growth wasobviously better after biochar application, plant height and effective leaf number were significantly higher than those ofcontrol, but total sugar and nicotine were not significantly different. The application of biochar at a rate of 1 200 kg/hm2 increased the potassium content by 11%, the application of biochar at a rate of 2 400 kg/hm2 improved total sugar content by 5.40%, and the application of biochar at a rate of 1 800 kg/hm2 made the tobacco solanone content 1.97 times as that of control. Comprehensive studies showed that the application of biochar 1 200-1 800 kg/hm2 could improvesoilenvironment, and promote tobacco growth and quality.
基金supported by the National Natural Science Foundation of China (Nos. 41877228, 41877229 and 42102303)Guangdong Basic and Applied Basic Research Foundation (Nos. 2018B030311066 and 2019A1515010554)+1 种基金China Postdoctoral Science Foundation (No. 2019M663241)Science and Technology Program of Guangzhou, China (No. 201904010136)。
文摘The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of granite residual soil in certain areas. Research on the mechanical properties and controlling mechanisms of disintegration has become a hot issue in practical engineering. In this paper, the disintegration characteristics of improved granite residual soil are studied by using a wet and dry cycle disintegration instrument, and the improvement mechanism is analyzed. The results show that the disintegration amounts and disintegration ratios of soil samples treated with different curing agents are obviously different. The disintegration process of improved granite residual soil can be roughly divided into 5 stages:the forcible water intrusion stage, microcrack and fissure development stage, curing and strengthening stage, stable stage, and sudden disintegration stage. The disintegration of granite residual soil is caused by the weakening of the cementation between soil particles under the action of water. When the disintegration force is greater than the anti-disintegration force of soil, the soil will disintegrate. Cement and lime mainly rely on ion exchange agglomeration, the inclusion effect of curing agents on soil particles, the hard coagulation reaction and carbonation to strengthen granite residual soil. Kaolinite mainly depends on the reversibility of its own cementation to improve and strengthen granite residual soil. The reversibility of kaolinite cementation is verified by investigating pure kaolinite with a tensile, soaking, drying and tensile test cycle. Research on the disintegration characteristics and disintegration mechanism of improved granite residual soil is of certain reference value for soil modification.
基金Project supported by the National Natural Science Foundation of China (No. 30270800).
文摘The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1) of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.
基金Major Research Plan of National Natural Science Foundation of China under Grant No.90815009the National Natural Science Foundation of China under Grant Nos.51108134,50378031 and 50178027
文摘A shake-table experiment on pile foundations in liquefi able soils composed of liquefi able sand and overlying soft clay is studied. A three-dimensional(3D) effective stress fi nite element(FE) analysis is employed to simulate the experiment. A recently developed multi-surface elasto-plastic constitutive model and a fully coupled dynamic inelastic FE formulation(u-p) are used to model the liquefaction behavior of the sand. The soil domains are discretized using a solid-fl uid fully coupled(u-p) 20-8 noded brick element. The pile is simulated using beam-column elements. Upon careful calibration, very good agreement is obtained between the computed and the measured dynamic behavior of the ground and the pile. A parametric analysis is also conducted on the model to investigate the effect of pile-pinning, pile diameter, pile stiffness, ground inclination angle, superstructure mass and pile head restraints on the ground improvement. It is found that the pile foundation has a noticeable pinning effect that reduces the lateral soil displacement. It is observed that a larger pile diameter and fi xed pile head restraints contribute to decreasing the lateral pile deformation; however, a higher ground inclination angle tends to increase the lateral pile head displacements and pile stiffness, and superstructure mass seems to effectively infl uence the lateral pile displacements.
基金supported financially by China’s National Foundation of Natural Sciences(41877324,41730641)Fundamental Research Funds for the Central Universities(2572017DG04,2572017EA03)+1 种基金13-5 Key Research and Development Project from China Ministry of Science and Technology(2016YFA0600802)Heilongjiang Province for Distinguished Young Scholars(JC201401)
文摘Glomalin-related soil protein(GRSP)sequesters large amounts of carbon and plays important roles in maintaining terrestrial soil ecosystem functions and ecological restoration;however,little is known about GRSP variation in 1-m soil profiles and its association with stand characteristics,soil properties,and climatic conditions,hindering GRSP-related degraded soil improvement and GRSP evaluation.In this study,we sampled soils from 1-m profiles from poplar(Populus spp.)shelterbelts in Northeast China.GRSP contents were 1.8–2.0 times higher in the upper 40 cm soil layers than at 40–100 cm.GRSP-related soil organic carbon(SOC)sequestration in deeper soil layers was*1.2 times higher than in surface layers.The amounts of GRSP-related nutrients were similar throughout the soil profile.A redundancy analysis showed that in both surface and deeper layers,soil properties(pH,electrical conductivity,water,SOC,and soil nutrients)explained the majority of the GRSP variation(59.5–84.2%);the second-most-important factor in GRSP regulation was climatic conditions(temperature,precipitation,and altitude),while specific shelterbelt characteristics had negligible effects(<5%).Soil depth and climate indirectly affected GRSP features via soil properties,as manifested by structural equation model analysis.Our findings demonstrate that GRSP is important for carbon storage in deep soils,regardless of shelterbelt characteristics.Future glomalin assessments should consider these vertical patterns and possible regulating mechanisms that are related to soil properties and climatic changes.
文摘The concept of using biological process in soil improvement which is known as bio-mediated soil improvement technique has shown greater potential in geotechnical engineering applications in terms of performance and environmental sustainability. This paper presents a review on the soil microorganisms responsible for this process, and factors that affect their metabolic activities and geometric compatibility with the soil particle sizes. Two mechanisms of biomineralization, i.e. biologically controlled and biologically induced mineralization, were also discussed. Environmental and other factors that may be encountered in situ during microbially induced calcite precipitation （MICP） and their influences on the process were identified and presented. Improvements in the engineering properties of soil such as strength/stiffness and permeability as evaluated in some studies were explored. Potential applications of the process in geotechnical engineering and the challenges of field application of the process were identified.
文摘Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added during chemical stabilization could improve the engineering properties of treated soils.Stabilizers utilized have to satisfy noticeable performance,durability,low price,and can be easily implemented.Since cement kiln dust(CKD) is industrial by-product,it would be a noble task if this waste material could be utilized for stabilization of sabkha soil.This study investigates the feasibility of utilizing CKD for improving the properties of sabkha soil.Soil samples are prepared with 2% cement and 10%,20% or 30% CKD and are tested to determine their unconfined compressive strength(UCS),soaked California bearing ratio(CBR) and durability.Mechanism of stabilization is studied utilizing advanced techniques,such as the scanning electron microscope(SEM),energy dispersive X-ray analysis(EDX),backscattered electron image(BEI) and X-ray diffraction analysis(XRD).It is noted that the sabkha soil mixed with 2% cement and 30% CKD could be used as a sub-base material in rigid pavements.The incorporation of CKD leads to technical and economic benefits.
文摘The bio-briquette technique which mixes coal, biomass and sulfur fixation agent and bio-briquettes under 3—5 t/cm 2 line pressure has aroused people's attention in view of controlling the air pollution and the acid rain. In this paper, the physicochemical properties of bio-briquette and its ash were investigated. And the acid soil was improved by the bio-briquette combustion ash, which contained nutritive substances such as P, N, K and had the acid-neutralizing capacity(ANC). The pH, EC, effective nutrient elements(Ca, Mg, K, P and N), heavy metal elements(Al, Cu, Cd, Cr, Zn and Mn) and acid-neutralizing capacity change of ash-added soils within the range of 0—10%, were also studied. Specially, when 5% bio-briquette combustion ash was added to the tested soil, the content of the effective elements such as Ca, Mg and K rose by 100 times, 7 times and twice, respectively. The total nitrogen also increased by about twice. The results showed the oxyanions such as that of Al, Cu, Cd, Cr, Zn and Mn were not potentially dangerous, because they were about the same as the averages of them in Chinese soil. It is shown that the ANC became stronger, though the ANC hardly increases in the ash-added soil. On the basis of the evaluation indices, it is concluded that the best mixture ratio is to add 2.5%—8% of the bio-briquette combustion ash to the tested soil.
文摘A detailed research in soil improving measure was conducted during the process of plants that were cultivated in Tianjin saline and alkaline area. The results showed that the commonly used measures could improve the soil, and also we got some useful advices and suggestions for plants cultivating in Tianiin saline and alkaline areas.
基金Project supported by Science&Technology Program of Hubei Traffic and Transport Office,ChinaProject(41272377)supported by the National Natural Science Foundation of China
文摘The weak intercalated soils in redbed soft rocks of Badong formation have obvious creep characters. In order to predict the unsaturated creep behaviors of weak intercalated soils, an unsaturated creep model was established based on the unsaturated creep tests of weak intercalated soils by using GDS triaxial apparatus. The results show that the creep behaviors of intercalated soils are apparent and significantly affected by matric suction. Based on this, an empirical Mesri creep model for intercalated soils under varying matric suctions was built. The fitting results show that the parameters Ed and m of this model are in good power relations with matric suction s and stress level Dr, respectively. An improved Mesri creep model was established involving stress-matric suction-strain-time, which is more precise than the Mesri creep model in predicting the unsaturated creep behaviors of weak intercalated soils.
基金Project(41902280)supported by the National Natural Science Foundation of ChinaProject(300102219105)supported by the Fundamental Research Funds for the Central Universities,China+1 种基金Project(LP1922)supported by the Open Foundation of State Key Laboratory of Coastal and Offshore Engineering,ChinaProject(XJKFJJ201805)supported by the Open Foundation of Shaanxi Key Laboratory of Safety and Durability of Concrete Structures,China。
文摘The use of electro-osmotic chemical is an effective method to improve the clayey soil foundation.Various boundary conditions can be adopted in this method.In this work,two electrode–clay contacts,three solution conditioners,and four anode solution supply times were used for clayey soil improvement.Based on the experimental data,electro-osmotic consolidation theory,and transport of ion theory,it is found that the electro-osmotic chemical effect of the separation of electrode–clay(E_S)is more beneficial for the transport of Ca^(2+),production of cementing material,and reduction of water content than that of electrode–clay(E_C)joining;through electrode–clay contact separation,the anode solution conditioner(NaPO3)6(E_SHMP)delayed the cementing reaction and then increased the transport of Ca^(2+)near the cathode,which increased the amount of cementing material and the electro-osmotic chemical effect;and when the anode conditioner(NaPO3)6 was used,two days of anode solution supply followed by three days cut off from the anode solution led to the highest undrained shear strength increase after the application of electro-osmotic chemical,which resolved the uneven electro-osmotic chemical effect in the E_SHMP.
