Physico-Chemical Properties of Soils from Diguel and Koudalwa Tchad,and Phytoremediation Potentials of Acasia and Kinkeliba Plants in Removing Cr and Cu from These Soils

The aim of this study to investigate the physico-chemical properties of soils from Diguel and Koudalwa Tchad,and phytoremediation potentials of acasia and kinkeliba plants in removing Cr and Cu from these soils.Soil was sampled from the tannery plant in Diguel and agricultural land around crude oil activities in Koudalwa.Soils were characterized by the following properties:pH,(Electrical Conductivity),TDS(Total Dissolved Solids),salinity,bulk density,OM(Organic Matter),nitrate,phosphate,clay,silt,sand,and textural class.The acasia and kinkeliba plants were used to decontaminate Cu and Cr from sample soils for 30 days period.The bulk density of all the soil samples from Kouldawa was higher compared to Diguil,ranging from 1.421 to 1.64 g/cm^(3)compared to 1.21 to 1.51 g/cm^(3)for Diguel.Most of the soils in Kouldawa are mineral soils,while those of Diguel are mostly mineral soil with some organics.Diguel soils are richer in nitrate(577.9 to 2,687.32 mg/kg in Diguel and 33.64 to 197.64 mg/kg in Kouldawa)and phosphate than soils from Kouldawa.Soils from the studied areas are not saline except for a subsurface soil in Diguel(salinity,4.21;EC,4.280 dS/m;TDS,3,040 mg/L).The highest amount of Cr and Cu removed by acasia is 78%and 53.12%compared to 73.8%and 52.21%by kinkeliba.Diguel soil can be very suitable for agriculture and Kouldawa soils for construction.Acasia and kinkeliba can be effectively used to decontaminate the studied soils from heavy metal pollution.

Effects of Plant Types on Physico-chemical Properties of Reclaimed Mining Soil in Inner Mongolia,China

A field experiment was conducted in Jungar Banner,Inner Mongolia,China to study the effects of plant types on the physical structure and chemical properties of open-cast mining soils reclaimed for 15 years,and to analyze the triggering factors of the soil formation.Results indicate that plant types affect soil-forming process especially in the upper layer (0-20 cm),and the spatial structure of reclaimed plant is the main reason for variability of the soil-forming process.In the upper soil layer at the site reclaimed with mixed plants,the concentrations of soil organic matter (SOM) and soil organic carbon (SOC) are the highest,and they were significantly higher at the sites reclaimed with Leymus chinensis,Caragana sinica,which is mainly due to a large amount of litter fall and root exudation in herbages and shrubs.However,the concentrations of SOM and SOC in the soils at the reclaimed sites are quite low comparing with those in local primary soil,which indicates the importance of using organic amendments during the ecological restoration in the study area.

Soil Physico-Chemical Properties and Microflora as Influenced by Bispyribac Sodium 10% SC in Transplanted Kharif Rice

The effects of bispyribac sodium 10% SC and butachlor 50% SC on soil physico-chemical properties and microflora in transplanted kharifrice were investigated over two seasons （2010 and 2011 ） Effects of the herbicide on bulk density, water holding capacity, moisture content, soil pH, organic matter content, electrical conductivity, as well as total nitrogen, available phosphorus and available potassium contents were analyzed along with microflora population （total bacteria, actinomycetes and fungi）. No significant changes in soil physico-chemical properties were observed. Herbicide treatments resulted in decreases in microbial counts initially. With the degradation of applied herbicides within a considerable time, the microflora populations even exceeded the initial count at 60 d after application of the herbicide.

Stndy on Soil Magnetic Effect

A study on the effect of applied magnetic field was performed with six types of soils collected fromnortheastern China. Magnetic field was found to cause changes of soil physicc-chemical properties and soilenzyme activities. An appropriate applied magnetic field could cut down soil zeta-potential, soil specificsurface, soil water potential and soil swelling capacity; raise the charge density on soil colloids and theactivities of invertase, hydrogen peroxidase and amylase in the soils; enhance soil aggregation and improvesoil structural status and soil water-releasing capability.

An Assessment of Soil Variability along a Toposequence in the Tropical Moist Semi-Deciduous Forest of Ghana

Understanding the variability of physico-chemical properties of soil along a toposequence is essential for smallholder farming communities. However, these resource constraint farmers in Ghana’s Moist Semi-Deciduous Forest (MSDF) zone poorly understand how slope positions affect soil properties. Therefore, soil variability assessment along a toposequence was carried out on Bekwai-Nzima/Oda compound association. From the summit to valley bottom slope positions, soil samples were taken at two depths (0 - 20 and 20 - 50 cm). As shown by the coefficient of variation, topsoil (0 - 20 cm) had the highest variation compared to the subsoil (20 - 50 cm). The variations observed in most soil attributes (clay, silt, pH, CEC, SOC and TN) for the 0 to 20 and 20 to 50 cm depths were between eroded (summit and upper slopes) and depositional (lower slope and valley bottom) zones. The highly variable soil attributes were silt, TN, Av. P, and Av. K. However, bulk density and sand were the least variable irrespective of soil depth or toposequence. Pearson correlation analysis indicated a significant correlation (p < 0.05) between most soil attributes at the 0 - 20 and 20 - 50 cm depths at different slope positions. Principal component (PC) analysis indicated that the first four PCs explained more than 80% and 70% of the total variation for the 0 - 20 and 20 - 50 cm soil depths, respectively. Statistically, our results revealed a significant effect of slope position on soil properties (p < 0.05) and topography influenced soil characteristics and development. Soil pH, sand, silt and clay contents were less affected by slope gradient, which confirms the inherent nature of these highly weathered tropical soils. The findings of this study can serve as a reference for the formulation of soil management strategies for smallholder farm communities.

Morphological, Physical and Chemical Characteristics of Hill Forest Soils at Chittagong University, Bangladesh

Forty five soil samples were collected from the four pedons of the hill areas at Chittagong University based on the depth of soil horizon. Soil profiles on hill top were relatively well developed and belonged to Ultisols according to USDA soil Taxonomy. The profiles at the piedmont were relatively young soils and classified as Inceptisols and Entisols. The soils of all profiles were characterized by coarse texture (38% to 73%, sand fraction), high bulk density (1.15 to 1.32 Mg·m-3), low organic-C content (0.26% to 1.73%), acid soil reaction ( varied from 4.44 to 5.52 and pHKCl from 3.57 to 4.90). Soils in all pedons were poor in exchangeable bases and base saturation. The CEC values ranged from 9.12 cmolc·kg-1 to 14.5 cmolc·kg-1 while ECEC varied from 1.96 to 4.78 cmolc·kg-1. The exchangeable Al (aluminum) concentration ranged from 0.41 to 0.66 cmolc·kg-1. Exchangeable acidity level ranged from 0.74 to 1.25 cmolc·kg-1. Exchangeable Al and aluminum saturation increased with depth and their concentrations were below the toxic range for tree stands. The study revealed that more young soils formed on the piedmont sites had somewhat better properties as compared to matured hill top soils. The variation in physico-chemical properties of the soils seemed to be influenced by the topography to a greater extent in the studied area.

改良剂与沼液配施对中度苏打盐碱土的改良效果研究

为了探究改良剂与沼液配施的合理方案,实现盐碱地改良,针对吉林省大安市盐碱地,通过大田试验,研究沼液与改良剂配施对苏打盐碱土的改良效果。试验结果表明,改良剂与沼液配施均能够有效提高土壤有机质、有效磷、速效钾、碱解氮的含量,增大总孔隙度,增加了土壤团聚体的数量,改善了土壤团聚体稳定性,水稻产量显著提升,并有效降低土壤pH值、土壤容重、碱化度、水溶性盐含量。综合分析,脱硫石膏与沼液配施对苏打盐碱土改良效果最好,对比未施用沼液的处理,有机质含量提升100%,有效磷含量提升34%,速效钾含量提升59%,碱解氮含量提升104%,总孔隙度提升14%,土壤团聚体数量显著增加,土壤团聚体稳定性得到明显改善,增产率为76.77%,土壤p H值降低12%,土壤容重降低9.9%,碱化度降低11%,水溶性盐含量降低48%。

水泥-碱渣固化高含水率海相软土力学性质试验研究

为了解决低剂量水泥单独固化高含水率海相软土早期强度不足及固废碱渣资源化利用率低等问题,采用水泥、碱渣联合固化高含水率软土。通过30种不同质量配比的无侧限抗压强度试验得出,水泥-碱渣固化高含水率海相软土试样的无侧限抗压强度不仅与水泥、碱渣的掺量有关,还受到软土含水率的控制。在无侧限抗压强度研究基础上,推荐优选配比(碱渣、软土、水泥质量比为30∶70∶6),其7 d无侧限抗压强度为682.7 kPa。优选配比固化土的加州承载比(CBR)和回弹模量满足各级公路路基填料的指标要求。通过对高含水率软土中水的影响以及固化土级配和微观结构分析得出,水泥-碱渣固化高含水率软土的力学强度主要来源于碱渣吸水作用、碱渣骨架作用以及各组分材料化学反应的作用。化学作用产生的C-S-H,C-A-H和Aft等凝胶物质共同密实结构,提高固化土强度。研究结果可为固废物固化高含水率软土在路基中的应用提供理论支持。

掺入粉煤灰软黏土的复合碱渣土力学特性探究

为探究承载性能优良且经济适用的碱渣地基土方案,设计了24种掺入粉煤灰和软黏土的复合碱渣土,并且综合无侧限抗压强度与经济指标,通过模糊评价法确定了复合碱渣土的最优配合比,同时对其进行了劈裂抗拉试验、静力三轴试验和蠕变试验.结果表明:软黏土、粉煤灰均对碱渣有明显加固作用,软黏土的加入可减少粉煤灰的用量,具备较好的经济适用性;复合碱渣土的劈裂抗拉强度与其无侧限抗压强度之比为0.15;固结围压对复合碱渣土不排水强度的影响最大,超固结比次之,固结比最小;当上部荷载未达到长期强度时,复合碱渣土的蠕变特征较为稳定且数值极小.

水泥-碱渣改良膨胀土干湿循环耐久性及其劣化机制试验研究

通过系统的室内试验对水泥-碱渣改良膨胀土的工程性质及其干湿循环耐久性进行评价,并通过微观测试技术分析了改良机理以及干湿循环劣化机制。结果表明,经水泥-碱渣改良后,膨胀土的液限、塑性指数和自由膨胀率明显减小,无侧限抗压强度显著增大;降低水泥-碱渣质量比引起的工程性质劣化可归因于复合型化合物CaO·SiO_(2)·CaCO_(3)·nH_(2)O的胶凝性能比典型水化胶凝产物弱。干湿循环初期,试样宏观形貌及无侧限抗压强度无明显变化;随着干湿循环次数的增加,试样强度明显减小,其宏观破坏特征表现为剥落。干湿循环作用下,改良土的微观劣化作用机制在于水化胶凝产物对土颗粒或团聚体的胶结作用遭到破坏,以及微裂缝的发育及扩张。

添加脱硫石膏对盐碱土壤入渗性能及土壤性质的影响

已有的科学研究和生产实践证明,添加脱硫石膏可以有效改良东北苏打盐碱土。但通过添加脱硫石膏如何影响土壤水分入渗性能及盐碱土性质的相关研究还比较缺乏。本文通过室内土柱淋洗试验,明确了土壤入渗效率随脱硫石膏用量的增加而增加,能够有效降低盐碱土的pH、EC、碱化度等,为盐碱土壤的改良修复提供了理论依据。

暗管条件下深松对苏打草甸碱土理化性质的影响

在田间管理模式一致的条件下,通过对无深松、无暗管与无配套措施(ck1),无深松、有暗管(暗管埋深0.8 m,埋管间距5 m)与有配套措施(施用猪粪34m3/hm2、MM改碱剂15 t/hm2)(ck2),以及有深松(深松深度分别为0.3m和0.6m)、有暗管与有配套措施(分别为S1和S2)处理的研究,得出了暗管条件下不同深松深度对苏打草甸碱土的渗透性、有机质含量以及碱化度、钠离子吸附比等理化性状的影响。结果表明:①与ck1、ck2相比,S1(0.3 m)、S2(0.6 m)处理能改善苏打草甸碱土的渗透性,其中,与ck1相比,ck2的K10(水温度为10℃时的透水率)增加了13.15倍,S1处理的K10增加了17.23倍,S2处理的K10增加了17.85倍。②与ck1、ck2相比,S1、S2的土壤微团聚体所占的比例均有所上升,且S2处理的效果较好。③与ck1相比,S1、S2处理的土壤有机质含量、碱解氮、有效磷、速效钾含量和阳离子交换量均有所增加,并且S2处理有机质含量较高,比ck1增加3.58 g/kg,比ck2增加0.94 g/kg。④与ck1、ck2相比,S1、S2处理均能降低土壤pH、电导率、全盐量、总碱度、碱化度和钠离子吸附比等,其中,S2处理的效果较好,各化学指标最低,分别为7.34、0.42 ms/cm、2.01 g/kg、2.336 cmol/kg、39.47%和2.405。在暗管条件下,土地深松处理能提高土壤的渗透性,降低土壤pH、电导率、全盐量、总碱度、碱化度和钠离子吸附比等指标,改善土壤理化性质,且土地深松0.6m的处理对苏打盐碱土的改良效果最好。

硫酸铝对苏打盐碱土的改良作用研究

苏打盐碱土添加硫酸铝后,土壤理化性状发生了显著改善。土壤物理性质表现为:土壤结构有显著改善,土壤团聚体(>0.005 mm)数量明显增加,土壤容重降低,膨胀度增加,孔隙度增大,土壤渗透性能及持水能力增强。土壤化学性质表现为:A l3+水解产生大量H+,降低了水田湛水层和土层的pH值;随硫酸铝用量的增加,土壤阳离子交换量呈显著递增,碱化度显著降低;CO32-和HCO3-含量也随硫酸铝用量的增加而降低。以上结果表明苏打盐碱土添加硫酸铝后,土壤结构得到良好改善,土壤盐分组成发生了显著变化,由苏打型→苏打-硫酸盐型→硫酸盐型。同时,苏打盐碱土理化性质的改良也为作物生长创造了良好的土壤环境。

鱼-稻-苇-蒲模式对苏打盐碱土的改良

对松嫩平原苏打盐碱地鱼-稻-苇-蒲开发模式土壤微生物和土壤化学性质进行了初步测定。结果表明:渔业开发后,土壤pH、含盐量平均下降了8.17%和43.57%,土壤有机质、全量N、P、K和速效性N、P、K均显著增加;土壤阳离子交换量和交换性盐基总量平均分别增加8.21%及27.71%。稻田、苇塘和蒲塘土壤微生物总量平均分别增加10.0倍、1.9倍和2.3倍;土壤酶的活性增强。排水洗盐对降低土壤含盐量的贡献率约为80%,稻秆、芦苇和蒲草的富集作用对降低土壤含盐性增强。排水洗盐对降低土壤含盐量的贡献率约为80%,稻秆、芦苇和蒲草的富集作用对降低土壤含盐量的贡献率约为10%。该模式对苏打盐碱土壤具有明显的改良效果。

利用碱渣和粉煤灰制取工程土的室内试验研究

碱渣是氨碱法生产纯碱时产生的工业废料,将碱渣与粉煤灰拌和制成工程土,并对其进行室内物理力学指标试验研究.结果表明,新型工程土无侧限抗压强度介于0.22～0.28 MPa之间,一定程度上能将其应用于工程实际,能够合理地解决碱渣废料的堆积及污染问题.

松嫩平原西部1-5年苏打碱化稻田的渗透性研究

运用亚甲基蓝着色和溴离子穿透实验两种方法,对连续种稻1年和5年的苏打碱土0-30 cm的透水性进行分析。结果表明：碱化稻田耕作层的质地和结构发生明显变化,并且土壤溶液下渗的深度和速率有明显的增加;1年稻田中染料可以下渗到20 cm;而5年稻田则可以渗透到整个耕作层。溴离子的穿透实验表明：经过16h后,入渗溶液只有82%溴离子渗出1年稻田的土柱;在5年稻田的土柱中,溴离子渗出浓度/入渗溶液浓度只需8h即可达95%,离子穿透过程近似达到平衡。

高硫煤矸石不同细度与用量对苏打盐化土化学性状的影响

根据山西省大同盆地苏打盐化土的特征,选取高硫煤矸石为研究对象,通过室内培养试验,重点研究了高硫煤矸石不同细度和不同用量对苏打盐化土的p H值、电导率(EC)、代换性钠离子含量和碱化度(ESP)等化学性状的影响。结果表明,施用高硫煤矸石后,苏打盐化土的p H值、代换性钠离子含量、碱化度(ESP)均有所降低,较对照分别降低了15.73%,28.57%,25.04%;而且随着高硫煤矸石用量的增加,各项指标的变化幅度增大,其中,以细度为0.21 mm、用量为9.6 t/hm2的高硫煤矸石对苏打盐化土的改良效果最为显著;施用高硫煤矸石会导致大量外源离子的输入,使苏打盐化土EC值与对照相比均有所升高,但通过调整土壤中盐离子的结构,使产生毒害作用的钠离子含量减少,对苏打盐化土起到良好的改良作用。

深松对松嫩平原苏打盐碱地土壤理化性质和玉米产量的影响

为构建合理耕层和改善耕作环境,设置不深松(CK)、春深松30和40 cm处理,秋深松30和40 cm处理,研究不同深松季节及深松深度对松嫩平原苏打盐碱土碱解氮、速效磷、有效钾、pH、阳离子交换量、有机质及玉米产量的影响。结果表明,深松可降低土壤pH,其中4个深松处理的土壤pH分别较CK降低了0.12%~3.00%。春深松30 cm、秋深松30 cm和秋深松40 cm处理的阳离子交换量较CK分别增加了6.08%、19.10%和5.30%。整体上深松处理均不同程度地提高了土壤的有机质、碱解氮、有效磷和速效钾含量,不同深松处理碱解氮含量差异达到极显著水平,有机质、有效磷和速效钾含量差异均不显著。不同处理穗长和行粒数无显著差异,穗粗和穗行数差异达到显著水平。深松有助于穗粗、穗行数和产量的增加,其中秋深松40 cm和秋深松30 cm处理分别较CK增产14.83%和11.51%。春深松40 cm和春深松30 cm处理分别较CK增产9.36%和10.52%。因此,秋季深松比春季深松和不深松对盐碱地玉米增产效果好。

种稻年限对苏打盐碱土理化性质及真菌群落的影响

【目的】研究不同种稻年限对苏打盐碱土理化性质及真菌群落的影响,为盐碱地改良提供理论依据。【方法】以分别种植水稻1年、3年、5年、15年、20年和50年的苏打盐碱地土壤为研究对象,通过常规分析和IlluminaMiSeq平台测序分析,对不同种稻年限苏打盐碱土基本理化性质及真菌在ITS1+ITS2区域的丰度和多样性进行研究。【结果】随种稻年限增加,苏打盐碱土的pH、电导率、总碱度以及水溶性盐分总量均显著下降;有机质和微生物量碳含量显著增加;全氮、铵态氮和硝态氮含量随种稻年限增加呈升高趋势;速效磷含量先显著增加,在种稻20年时达最大值,之后略有下降;速效钾含量没有明显变化规律。种稻1年、3年、5年、15年、20年和50年的土壤中获得的真菌有效序列数量分别为56 942、42 482、45 987、92 214、64 665与68 515,包括5门12纲25目26科45属59种,其中枝孢菌属Cladosporium、霍特曼尼菌属Holtermanniella和马氏链球菌属Massariosphaeria为优势菌属,相对丰度均大于2%。α多样性指数随种稻年限增加先增大后逐渐减小,种稻5年时最大。土壤pH、电导率、总碱度、水溶性盐分总量和速效钾含量是影响种稻后苏打盐碱土真菌群落结构的主要环境因素。【结论】种植水稻可以明显改变苏打盐碱土基本理化性质和真菌群落结构,促进苏打盐碱土的改良。

围栏草原与放牧草原对苏打盐碱土理化性状的影响

[目的]探明苏打盐碱化土壤在不同利用方式下土壤的物理特性及化学特性的变化趋势,为其改良利用和生态恢复提供理论依据。[方法]采集围栏草原与放牧草原2个剖面的8个分层土样,并测定土壤容重、电导率、pH值、碱化度及土壤孔隙度。[结果]围栏草原土壤各层容重、电导率、碱化度及总碱度均低于放牧草原;围栏草原土壤除表层的pH值明显低于退化草原外,其他各层pH值与放牧草原无明显差异;围栏草原土壤孔隙度明显高于放牧草原。[结论]该研究结果表明放牧草原的盐渍化程度较围栏草原严重。