Impact of Initial Soil Conditions on Soil Hydrothermal and Surface Energy Fluxes in the Permafrost Region of the Tibetan Plateau

Accurate initial soil conditions play a crucial role in simulating soil hydrothermal and surface energy fluxes in land surface process modeling.This study emphasized the influence of the initial soil temperature(ST)and soil moisture(SM)conditions on a land surface energy and water simulation in the permafrost region in the Tibetan Plateau(TP)using the Community Land Model version 5.0(CLM5.0).The results indicate that the default initial schemes for ST and SM in CLM5.0 were simplistic,and inaccurately represented the soil characteristics of permafrost in the TP which led to underestimating ST during the freezing period while overestimating ST and underestimating SLW during the thawing period at the XDT site.Applying the long-term spin-up method to obtain initial soil conditions has only led to limited improvement in simulating soil hydrothermal and surface energy fluxes.The modified initial soil schemes proposed in this study comprehensively incorporate the characteristics of permafrost,which coexists with soil liquid water(SLW),and soil ice(SI)when the ST is below freezing temperature,effectively enhancing the accuracy of the simulated soil hydrothermal and surface energy fluxes.Consequently,the modified initial soil schemes greatly improved upon the results achieved through the long-term spin-up method.Three modified initial soil schemes experiments resulted in a 64%,88%,and 77%reduction in the average mean bias error(MBE)of ST,and a 13%,21%,and 19%reduction in the average root-mean-square error(RMSE)of SLW compared to the default simulation results.Also,the average MBE of net radiation was reduced by 7%,22%,and 21%.

Soil conditioners improve Cd-contaminated farmland soil microbial communities to inhibit Cd accumulation in rice

The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.

Control Effects of Tianshifu Soil Conditioners on Cd Contamination in Paddy Fields of Hunan Province

To investigate the effects of Tianshifu soil conditioners on rice growth and their control effects on Cd absorption and accumulation in rice, a test was carded out in the field typically polluted by Cd in Hunan Province. The results showed that the Tianshifu soil conditioner, soil bacterial conditioner and the combination of Tian- shifu soil conditioner and soil bacterial conditioner all could promote rice growth, im- prove rice yield and reduce significantly Cd content in rice grains. In Beishan, the Cd contents in rice grains treated by Tianshifu soil conditioner, soil bacterial condi- tioner and the combination of Tianshifu soil conditioner and soil bacterial conditioner were reduced by 37.63% （P〈0.05）, 32.59% （P〈0.05） and 27.95% （P〈0.05） respec- tively compared with that in rice grains treated by conventional fertilization; In Xiang- tan, the Cd contents in rice grains were reduced by 54.36% （P〈0.05）, 50.19% （P〈 0.05） and 45.22% （P〈0.05） respectively. The rice grains harvested at the two test sites all met the national food safety standards. Considering the control effect on Cd contamination, Tianshifu soil conditioner 〉 combination of Tianshifu soil condi- tioner and soil bacterial conditioner 〉 Tianshifu soil bacterial conditioner. In addition to reducing Cd absorption in rice, as described in the lime application treatment, the application of Tianshifu soil conditioners also inhibited the transportation of Cd from rice straws to rice grains. The Tianshifu soil conditioner, soil bacterial conditioner and combination of Tianshifu soil conditioner and soil bacterial conditioner also effec- tively improved the soil acidity, increased the soil pH value and reduced soil avail- able Cd content to some extent.

Effects of Multiple Soil Conditioners on a Mine Site Acid Sulfate Soil for Vetiver Growth

A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate.

Seismic fragility of structures isolated by single concave sliding devices for different soil conditions

This study deals with the seismic fragility of elastic structural systems equipped with single concave sliding（friction pendulum system（FPS）） isolators considering different soil conditions. The behavior of these systems is analyzed by employing a two-degree-of-freedom model, whereas the FPS response is described by means of a velocity-dependent model. The uncertainty in the seismic inputs is taken into account by considering artificial seismic excitations modelled as timemodulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. In particular, the filter parameters, which control the frequency content of the random excitations, are calibrated to describe stiff, medium and soft soil conditions. The sliding friction coefficient at large velocity is also considered as a random variable modelled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities of exceeding different limit states related to both the reinforced concrete（RC） superstructure and isolation level, defining the seismic fragility curves within an extensive parametric study carried out for different structural system properties and soil conditions. The abovementioned seismic fragility curves are useful to evaluate the seismic reliability of base-isolated elastic systems equipped with FPS and located in any site for any soil condition.

Remediation Effects of Soil Conditioners for CdPolluted Paddy Fields

A field experiment was conducted to evaluate the remediation effects of 14 soil conditioners for Cd-polluted paddy fields contrasted with conventional fertilization and liming.The results showed that soil conditioners had no significant impact on rice yields.Though the soil conditioners had stable effects on decreasing the Cd content in grains,the effects varied with the category of conditioners.In general,The Cd contents of early rice and late rice were reduced by 22.65%~44.24%and 15.20%~63.03%,respectively.Additionally,the stem and leaves showed the same decreasing tendency.Cluster analysis suggested that soil conditioners can be divided into three categories:the first category increases the soil pH to inhibit the Cd activity and cut down the Cd translocation from soil to stem and leaves,which is most efficient in the reduction of Cd content in rice grains;the other category relies on the antagonism or co-precipitation between Cd and certain elements to inhibit the translocation and redistribution of Cd from rice stems to grains,providing a common effect on Cd reduction;the last category can be seen as a combination of the former two categories from the perspective of its functional mechanism and it has a moderate effect on the reduction of Cd contents in rice grains.

Effect of Soil Conditioner on the Microbial Community in the Rhizosphere Soil of Tobacco

The effects of biochar as a soil conditioner on microbial communities were studied. The results showed that, at all the growth stages of tobacco, the quantity of microorganisms in the rhizosphere soil added with the soil conditioner was higher than control （CK）. The results of metagenome detection indicated that the diversity of microbial communities in soil added with the soil conditioner was also higher than the CK, and the rate of tobacco bacterial wilt and the disease index decreased by 27.6% and 34.6%, respectively, compared with the CK. In conclusion, the soil con- ditioner could reduce the soil-borne disease by improving micro-ecological environ- ment and diversity of microbial communities in rhizosphere soil to maintain the soil balance.

Influences of Oyster Shell Soil Conditioner on Soil and Plant Rhizospheric Microorganisms

Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass,respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric microorganisms, especially nitrogen-fixers, and intensify soil respiration in proportion to the dose and fertilizing time of the conditioner, leading to the increase in the number of nitrogen fixing bacteria and the decrease in the number of bacteria with special nutrition demands.

Remediation Effects of a Novel Soil Conditioner onCadmium and Arsenic Contaminated Soil in Early-Season Paddy Field

To investigate the effects of“Runbang”soil conditioner on simultaneously decreasing cadmium(Cd)and arsenic(As)in early-season paddy field,a typical red mud field in Hunan Province was selected for monitoring the dynamic changes of Cd and As contents in early-season rice plants and soils,plus the soil physical-chemical properties and rice yields.Results of the field experiments indicated that the soil conditioner could significantly reduce Cd and As contents in soil and rice grain,whereas it could increase rice yield.Applying Runbang soil conditioner(1500~2100 kg/hm^2)to paddies brought about a reduction of 23.7%~44.8% and 24.3%~40.5% in available Cd and As contents of the soil,an increase of 0.9~1.1 units in soil pH value,a decline of 35.6%~51.1% and 22.0%~40.6% in Cd and As contents of rice grains,and a rise of 2%~5% in rice yields,respectively.

Utilization of Agricultural Waste for Production of Soil Conditioner-Case Study

In the present study,reference is made to a pigsty with an estimated total animal weight of 500,000 kg.The quantities and quality(typical characteristics)of the generated waste are calculated.The total waste occurs after the cleaning washes in the premises of the breeding unit.Semi-liquid waste is treated in solid-liquid phase mechanical separation plants.The resulting solids,waste(reduced humidity),go to storage areas,manure.These areas are shaped concrete basins,in which there is aerobic digestion“composting”.This process results in odorless organochumic material which is further used as a soil conditioner.

Anaerobic Mono-Digestion of Turkey Manure: Efficient Revaluation to Obtain Methane and Soil Conditioner

This work demonstrates the possibility to make a full valuation of a solid waste such as turkey manure, to obtain methane and a soil conditioner/fertilizer from turkey manure anaerobic digestion in a mesophilic pilot-scale continuous stirred tank reactor at different organic loading rates (OLR) (from 0.5 to 2.5 kgVS/m3d). The application of the anaerobic mono-digestion for the turkey manure treatment was an efficient alternative, because high volatile solids removal and methane were obtained in addition to obtaining a stabilized solid waste that can be applied as soil conditioner, based on its nutritional parameters and humic substances content. In this way, the turkey manure anaerobic digestion can be applied avoiding the co-digestion of the manure with other wastes and allows a process devoid of pollutant emissions, obtaining two products. The reactor operation depends on the OLR, and its operation does not allow an OLR above 1.5 kgVS/m3d. Higher OLR produced a decrease in the TS and VS removals and methane productivity.

Characteristics of In-Situ Soil Water Hysteresis Observed through Multiple-Years Monitoring

A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil water potential ψ to volumetric water content θ of the soil. However, an in-situ ψ − θ relation should show soil water hysteresis, though this fact is often neglected in analyses of field soil water regimes while long-term in-situ soil water hysteresis is not well characterized. This study aimed at probing and characterizing in-situ ψ − θ relations. The developments of large hysteresis in the in-situ ψ − θ relations were observed only a few times during the study period of 82 months. Any of the large hysteretic behaviors in the ψ − θ relations began with an unusually strong continual reduction in ψ. The completion of a hysteresis loop required a recorded maximum rainfall. Because the study field had very small chances to meet such strong rainfall events, it took multiple years to restore the fraction of soil water depleted by the unusually strong continual reduction in ψ. While wetting-drying cycles had occurred within a certain domain of ψ, hysteretic behaviors tended to be so small that the in-situ ψ − θ relation can be approximated as a single-valued function of θ(ψ). These observed patterns of the in-situ ψ − θ relations were characterized by kinds of difference in dθ/dψ between a drying process and a wetting process at a given ψ. Thus, more amounts of experimental facts about wetting SWRCs in parallel with drying SWRCs should be needed for correct modelling, analyzing, and predicting soil water regimes in fields. It is also necessary to increase our understandings about the long-term trends of occurrences of extreme weather conditions associated with possible change in climate.

Mechanized Tunneling in Soft Soils： Choice of Excavation Mode and Application of Soil-Conditioning Additives in Glacial Deposits

The history of the formation of the alpine region is affected by the activities of the glaciers, which have a strong influence on underground works in this area. Mechanized tunneling must adapt to the presence of sound and altered rock, as well as to inhomogeneous soil layers that range from permeable gravel to soft clay sediments along the same tunnel. This article focuses on past experiences with tunnel-boring machines （TBMs） in Switzerland, and specifically on the aspects of soil conditioning during a passage through inhomogeneous soft soils. Most tunnels in the past were drilled using the slurry mode （SM）, in which the application of different additives was mainly limited to difficult zones of high permeability and stoppages for tool change and modification. For drillings with the less common earth pressure balanced mode （EPBM）, continuous foam conditioning and the additional use of polymer and bentonite have proven to be successful. The use of conditioning additives led to new challenges during separation of the slurries （for SM） and disposal of the excavated soil （for EPBM）. If the disposal of chemically treated soft soil mate- rial from the earth pressure balanced （EPB） drive in a manner that is compliant with environmental legislation is considered early on in the design and evaluation of the excavation mode, the EPBM can be beneficial for tunnels bored in glacial deposits.

Soil conditioning tests of clay for EPB tunnelling

Tunnelling with earth pressure balance-tunnel boring machine(EPB-TBM)in clayey soil requires a careful conditioning to reduce the effect of clogging and stickiness.In the last decade,many researches have been carried out to understand how to reduce these negative behaviors using conditioning agents,and different laboratory test procedures have been proposed using both powdered clay and clay chips to quantify and assess the effect of conditioning in terms of reduction of clogging and stickiness.In this paper a review of the various proposed tests is presented.Unfortunately,it can be seen that no unified assessment method on the soil conditioning is available and therefore the designers do not have consistent data on which their choices are based.The present research proposes a laboratory test methodology to study clay conditioning taking both the behavior of chips and powdered clay into account.The proposed procedure has been applied on two different clays,and the test results are presented and discussed to show how the proposed methodology could be applied.

Spatial variability of leaf wetness under different soil water conditions in rainfed jujube (Ziziphus jujuba Mill.) in the loess hilly region, China

Leaf wetness provides a wide range of benefits not only to leaves,but also to ecosystems and communities.It regulates canopy eco-hydrological processes and drives spatial differences in hydrological flux.In spite of these functions,little remains known about the spatial distribution of leaf wetness under different soil water conditions.Leaf wetness measurements at the top(180 cm),middle(135 cm),and bottom(85 cm)of the canopy positions of rainfed jujube(Ziziphus jujuba Mill.)in the Chinese loess hilly region were obtained along with meteorological and soil water conditions during the growing seasons in 2019 and 2020.Under soil water non-deficit condition,the frequency of occurrence of leaf wetness was 5.45%higher at the top than at the middle and bottom of the canopy positions.The frequency of occurrence of leaf wetness at the top,middle and bottom of the canopy positions was over 80%at 17:00‒18:00(LST).However,the occurrence of leaf wetness at the top was earlier than those at the middle and bottom of the canopy positions.Correspondingly,leaf drying at the top was also latter than those at the middle and bottom of the canopy positions.Leaf wetness duration at the middle was similar to that at the bottom of the canopy position,but about 1.46-3.01 h less than that at the top.Under soil water deficit condition,the frequency of occurrence of leaf wetness(4.92%-45.45%)followed the order of top>middle>bottom of the canopy position.As the onset of leaf wetness was delayed,the onset of wet leaf drying was advanced and the leaf wetness duration was shortened.Leaf wetness duration at the top was linearly related(R^(2)>0.70)to those at the middle and bottom of the canopy positions under different soil water conditions.In conclusion,the hydrological processes at canopy surfaces of rainfed jujube depended on the position of leaves,thus adjusting canopy structure to redistribute hydrological process is a way to meet the water need of jujube.

Biochemical Characteristics of Saint Mary’s Thistle Varieties (<i>Silybum marianum</i>L. <i>Gaertn.</i>) under Soil-Climate Conditions of the Khorezm Region

This article deals with the biochemical characteristics of varieties of Saint Mary’s Thistle such as Panacea, Debut and Samaryanka. Based on the studies, it was found that the highest oil content was found in the species Debut (26%). The lowest oil content was observed in the variety Samaryanka (19%). The highest protein content and the sum of total amino acids in the seeds of St. Mary’s Thistle varieties were found in the variety Debut (131.1), and the lowest indication was observed in the species Samaryanka (79.2). By the number of replaceable amino acids existing in the seeds of the species of St. Mary’s Thistle, it was found in the Varieties Debut (126.3), and the lowest indication was observed in the variety Samaryanka (112). Based on the results of studies and the noted biochemical characteristics and varietal differences of the St. Mary’s Thistle, the possibility and expediency of expanding the crops of this species in the soil and climatic conditions of the Khorezm region are suggested. The research was conducted 2017-2019 y.

土壤改良剂对连作草莓生长及品质的影响

为明确土壤改良剂的作用效果,选择连作13年草莓田土壤,以宁玉为试材,研究了莓园土∶自主研发改良剂=2∶1(ZYF-1)、莓园土∶自主研发改良剂=3∶1(ZYF-2)、莓园土∶营养土=1∶1(YYT-1)、莓园土∶营养土=1∶2(YYT-2)及莓园土(CK)5种不同处理对草莓生长及果实品质的影响。结果表明,不同处理均可提前草莓生长物候期。定植28 d,处理ZYF-2草莓株高、茎粗最大,显著高于CK。定植40 d,处理YYT-2、ZYF-2草莓根系活力、叶绿素含量显著大于CK,且草莓成熟期单株产量分别增加了15.76%、17.05%。不同处理对草莓果实品质影响较小,处理ZYF-2草莓可溶性固形物含量最大、糖酸比最高,分别较CK高3.01%、9.10%。处理YYT-2草莓维生素C含量最大,较CK高6.11%。

施用有机肥和调理剂对田间土壤重金属有效态变化影响及水稻降镉效应研究

以春优84和中浙优8号为试验材料,在浙江衢州典型镉污染农田开展大田小区试验,研究有机肥与土壤调理剂施用对土壤酸碱度(pH)、土壤重金属元素(Cd、Fe、Mn、Zn等)有效态、水稻植株(稻草、籽粒)重金属元素积累量的影响,并探究了施用有机肥与土壤调理剂降低籽粒Cd积累的机理。结果表明,单施有机肥(1.5 t/hm^(2))对土壤金属元素有效态、稻草和籽粒重金属元素含量无显著影响;在有机肥(1.5 t/hm^(2))+土壤调理剂(2.7 t/hm^(2))联合施用处理后,土壤pH增加9.48%,土壤重金属有效态含量和植株中重金属元素含量均呈下降趋势。其中,土壤有效态Cd含量降低16.41%(DTPA提取)和48.96%(CaCl_(2)提取),稻草和籽粒Cd含量分别降低40.04%和48.22%。逐步回归和通径分析表明,稻草Cd含量、土壤Cd有效态与籽粒Cd含量显著相关。由此可见,施用土壤调理剂通过提升土壤pH,从而降低土壤重金属元素有效态含量,其中有效态Cd含量下降尤为显著,以此调控水稻稻草和籽粒中的Cd积累。说明供试土壤调理剂可以在酸性土地区推广应用,具有提升酸性土壤pH、降低稻米Cd富集的效果。

两种调理剂对水稻土pH值和重金属吸收的影响

探明两种调理剂对近中性水稻土pH值、重金属有效性和水稻吸收的影响,及其与土壤性质的关系,为调理剂的科学开发及合理施用提供科学依据。选取水淬高炉渣源调理剂(T1)及其腐殖质改性调理剂(T2),分别设置2个施用量梯度(T1L、T1H和T2L、T2H),通过盆栽试验分析了两种调理剂及不同用量对土壤pH值、有效硅、镉、锌、铜含量,以及水稻籽粒和秸秆镉、锌、铜含量的影响。与对照(CK)相比,2个施用T1调理剂处理土壤pH值分别升高0.64和1.02,2个施用T2调理剂处理pH值分别升高0.27和0.56(P<0.05),土壤pH值随调理剂施用量的增加而增加。T1L和T1H处理土壤有效硅含量与CK相比分别提高5和22倍(P<0.05),且显著高于施用T2调理剂处理。与CK相比,T1H处理土壤有效镉、锌、铜含量分别降低37.21%、45.57%和95.30%(P<0.05);T2L和T2H处理土壤有效锌含量分别降低31.55%和30.67%,有效铜含量分别降低6.53%和19.32%(P<0.05)。与CK相比,T1L和T1H水稻籽粒锌含量分别降低23.44%和18.12%(P<0.05);施用T2调理剂后,籽粒和秸秆锌、铜含量无显著变化。土壤pH值、有效硅含量与土壤有效镉、锌、铜含量呈显著或极显著负相关,土壤有效硅含量与籽粒、秸秆镉含量呈显著负相关。研究表明,在近中性水稻土上施用富含硅的强碱性调理剂,既有利于提高土壤p H值和有效硅含量,又可有效降低土壤重金属有效性及其水稻吸收量。