冀中南棉区土壤钠的形态与棉花吸收的关系

对河北省中南部棉区36个地块土壤钠形态和含量进行了测定。结果表明,冀中南棉田土壤0—20cm全钠含量为10.7～24.6g kg;交换性钠含量为48～10250mg kg,水溶性钠含量为21.5～10400.5mg kg。土壤全钠含量与交换性钠含量、水溶性钠含量之间及土壤交换性钠含量与水溶性钠含量之间均呈正相关关系;土壤全钠含量与土壤有机质含量、土壤阳离子交换量之间呈负相关关系;土壤交换性钠含量、水溶性钠含量与土壤阳离子交换量之间呈负相关关系;水浇地棉田土壤全钠含量与水溶性钠含量之间呈负相关关系。从供试土壤全钠含量为14 1～17 6g kg,交换性钠含量为39 0～189 0mg kg,水溶性钠含量为19 5～114 0mg kg条件下的盆栽试验结果看出,棉花苗期干物质积累量与土壤交换性钠含量、土壤水溶性钠含量之间以及棉花苗期钠吸收量与土壤交换性钠含量、水溶性钠含量之间均呈曲线相关关系。

磁化不同水质滴灌对土壤盐分的影响

【目的】研究磁化不同水质和电解水滴灌对盐碱土壤盐分的影响。【方法】以121团6连盐碱土为研究对象,通过室内土柱试验,对比分析微咸水、磁化微咸水、磁化渠道水、渠道水和电解水滴灌对盐碱土壤总盐含量、脱盐率、土壤盐分离子以及土壤SAR的影响规律。【结果】土壤剖面平均总盐含量大小比较为T_(1)>T_(2)>CK>T_(3)>T_(4)。磁化微咸水灌溉处理在土层深度30~40cm以及深层土壤内总盐含量显著低于微咸水灌溉处理,磁化渠道水灌溉处理在40cm土层深度以下土壤总盐含量显著低于渠道水灌溉处理。各处理土壤剖面脱盐区的平均脱盐率大小比较为T_(4)>T_(3)>T_(2)>CK>T_(1),脱盐率达到51.8%~59.36%。与对照处理比较,微咸水灌溉处理土壤剖面脱盐区的平均脱盐率降低了2.18%,磁化微咸水处理增加了7.2%,磁化渠道水处理增加了8.99%,电解水处理增加了13.25%。磁化渠水滴灌有利于增加土壤中Ca^(2+)含量,较滴灌前增加72.59%;同时降低Cl^(-)、Na^(+)和HCO^(-)_(3)含量,降幅为92.23%、67.49%和30.84%。而电解水灌溉有利于土壤剖面SO^(2-)_(4)淋洗脱盐,脱盐率为34.09%。磁化渠道水灌溉处理显著降低0~50 cm土层深度处土壤SAR。【结论】磁化水灌溉处理在降低土壤平均总盐含量和增大土壤脱盐率方面优于非磁化水灌溉处理,而电解水灌溉处理最优。电解水和磁化水灌溉有利于土壤盐分和有害盐分离子淋洗脱盐。

缩节胺和硝普钠对棉花幼苗根际土壤酶活性及细菌群落的影响

【目的】研究棉花幼苗施用缩节胺(1,1-dimethyl piperidinium chloride,DPC)和一氧化氮供体硝普钠(sodium nitroprusside,SNP)后根际土壤酶活性及细菌群落的变化,探讨与棉花幼苗生长相关的根际生物学指标。【方法】采用陆地棉品系A201进行穴盘育苗试验。于棉花1叶1心期分别在叶片均匀涂抹50 mg·L^(-1)DPC、500μmol·L^(-1)SNP,以涂抹去离子水为对照。于3叶1心期取根际土壤分析蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶活性,采用16S rRNA测序技术分析根际细菌多样性。【结果】DPC和SNP处理显著促进棉花根系生长,显著提高茎粗和植株干物质质量。DPC处理显著提高土壤脲酶和蔗糖酶的活性,SNP处理显著提高土壤蔗糖酶活性但显著降低脲酶的活性,但是DPC和SNP处理均未显著影响过氧化氢酶和碱性磷酸酶活性。DPC处理显著提高髌骨菌门(Patescibacteria)的相对丰度和土壤细菌群落的辛普森多样性指数(Simpson's diversity index),显著降低了绿弯菌门(Chloroflexi)和酸杆菌门(Acidobacteria)的相对丰度以及土壤细菌群落的香农-维纳多样性指数(Shannon Wiener’s diversity index)。冗余分析显示,DPC处理组的酵母菌科(Saccharimonadaceae)、TM7a属细菌的相对丰度比SNP处理组和对照组高;SNP处理组的纤维弧菌属(Cellvibrionaceae)细菌相对丰度高于DPC处理组和对照组;DPC和SNP处理组的根瘤菌科(Rhizobiaceae)细菌的相对丰度高于对照组,硝化螺旋菌科(Nitrospiraceae)和硝化螺旋菌属(Nitrospira)细菌的相对丰度低于对照组。脲酶活性与酵母菌科、TM7a属细菌的相对丰度呈显著正相关关系。【结论】DPC和SNP能够促进棉花幼苗根系及植株生长,并影响棉苗根际的土壤酶活性及细菌群落结构。

田间管理措施对滨海盐渍地区中低产田生产力的影响

为探究提高滨海盐渍化农田农业生产力的集约化种植方案,从2015年开始在山东省垦利区开展田间定位试验,综合考虑施肥量、施肥时期、种植密度、土壤改良剂等措施,试验设置农户习惯(farmer’s practice,FP)、土壤改良(improved soil management,ISM)、作物调控(improved crops management,ICM)和土壤作物综合调控(integrated soil crop management,ISCM)4个处理,追踪小麦关键生育期的群体动态变化,分析小麦、玉米收获期干物质积累量和植株的氮磷钾养分吸收量,调查小麦、玉米产量及产量构成因素的变化,比较作物生产净收益、收获期0—20 cm土层的土壤脱钠率和钠吸附比。结果表明,相较于FP处理,ISM显著增加了小麦和玉米收获期穗数,最终产量分别提高25.2%和10.0%,净收入提高7.8%。此外,ISM处理土壤脱钠率达78.6%;ICM处理显著提高了小麦和玉米的群体干物质积累量,相较FP处理产量分别提高17.8%和10.7%,净收入增加19.3%;ISCM处理获得试验条件下小麦、玉米最大产量,分别为11.96和10.83 t·hm^(-2),净收入比FP处理提升20.8%,土壤脱钠率达82.9%。ISM处理能显著降低滨海盐渍土的钠离子含量,提高小麦玉米养分吸收能力并增加产量;ICM处理虽然增产效果低于ISM处理,但较低的投入成本能够获得更高的净效益。综合来看,ISCM处理能够协同实现土壤质量提升、作物增产和经济效益增加,是该研究条件下最优管理实践方案。研究结果可为区域中低产田产能提升提供技术理论支撑和示范样板。

ESP值和黏粒含量对土壤表面封闭作用的影响

降雨导致土壤表面结皮形成封闭是自然现象,它能降低土壤入渗,增加土表径流,导致土壤侵蚀。该文系统地研究了不同性质土壤表面的封闭作用过程,分别确定封闭过程中的物理机械作用和化学作用。试验采用了具有不同土壤交换性钠百分率(ESP)值(2、5、10、20)和黏粒含量(10%、20%、40%、60%)的4种土壤进行降雨模拟试验,通过土壤表面播撒磷石膏(PG)(2000 kg/hm2)和PG与聚丙烯酰胺(PAM)(PG 2000 kg/hm2+PAM 20 kg/hm2)混合物的处理,分别抑制了土壤的化学封闭和物理封闭,论述了ESP值和黏粒含量对土壤化学封闭和物理封闭作用的影响,结果表明:在高ESP值土壤中,化学封闭作用占土壤封闭的主导作用;低ESP值土壤中,土壤的物理封闭作用增大。当黏粒含量较低时,土壤物理封闭作用较低;当黏粒含量较大时,土壤物理封闭作用显著增大。

杭州湾滩涂Na元素含量对植物多样性和优势度的影响

钠元素是滩涂湿地土壤盐分的最主要成分。利用样方法调查了杭州湾滩涂湿地的植物多样性及其分布,以及土壤钠含量对植物多样性和优势度的影响,用相关回归方法对数据进行分析处理。结果表明:(1)海塘内的物种多样性要高于海塘外,有11种植物,优势植物是芦苇(Phragmites australis)和互花米草(Spartina alterniflora),且互花米草的优势度要高于芦苇;但是在海塘外的自然滩涂,则只出现3种植物,主要优势植物是互花米草和海三棱藨草(Scirpus xmariqueter),芦苇则较为少见。在海塘外的海三棱藨草-互花米草混合群落中,海三棱藨草的优势度要高于互花米草。(2)物种丰富度指数(Margalef指数)和物种多样性(Simpson指数)指数均与土壤钠含量呈极显著负相关关系,通过回归分析得回归方程分别为y(Margalef指数)=-0.05x+1.608(R2=0.732,P<0.01,n=10),y(Simpson指数)=-0.038x+1.214(R2=0.926,P<0.01,n=10)。(3)海塘内互花米草的重要值与土壤钠含量呈极显著正相关,y=0.033x-0.007(R2=0.802,P<0.01,n=10);而芦苇重要值则与其呈极显著负相关,y=-0.013x+0.419(R2=0.607,P<0.01,n=10)。在海塘外的混合群落中,互花米草和海三棱藨草的重要值与土壤钠含量之间没有明显的相关关系。(4)随着(海塘)围垦时间的延长,其物种多样性呈现增大的趋势,中生植物更为丰富,而盐生植物逐渐萎缩。

杨树林地处理生活污水生态效应

为了研究不同污水水力负荷对不同杨树品种人工林的影响,选择了‘I-72’、‘欧美107’、‘中林2001’与‘中林46’四个杨树品种,分别按照3、6、9、12、15 cm·周^(-1)5个水力负荷进行污水处理;测定试验期间各品种地上部分生长量、凋落物量与污染物积累量。结果表明:3~9 cm·周^(-1)水力负荷增加了‘I-72’、‘中林2001’、‘欧美107’的生长量、凋落物量与污染物积累量;水力负荷大于9 cm·周^(-1)时,这3个杨树品种生长量、凋落物量与污染物积累量随着水力负荷增加而降低。在这3个品种中,‘中林2001’年生长量与污染物积累量最大,‘欧美107’中等,‘I-72’最低。从杨树生长量与污染物积累量来看,‘中林2001’最适合作为污水处理的植物材料,其次是‘欧美107’、I-72杨,污水处理的适宜水力负荷为6~9 cm·周^(-1),‘中林46’不适合用于污水处理。

Effects of Inorganic Sodium Salt in Soil on Concentration of Zinc Ion in Different Patterns

[Objective] The aim was to study on effects of inorganic sodium salt in soil on concentration of zinc ion in different patterns. [Method] Tessier sequential extraction was used to study on effects of inorganic sodium salts （in different species and different concentrations） on concentration of zinc ion in different patterns. [Result] Different inorganic sodium salts had different effects on zinc form. Content of ex- changeable Zn would reduce if Na2CO3 or Na2SO4 was added and the content would increase if NaCI was added. Content of carbonate zinc, which was significantly influ- enced by Na2SO4, would increase if NaCI or Na2SO4 was added, and would decrease if Na2CO3 was added. For Zn bound to Fe-Mn oxides and organic matters, and residual Zn, the contents would decrease if NaCI or Na2SO4 was added and the decrease showed much more significantly if high concentration sodium salts were added. In addition, content of Zn bound to Fe-Mn oxides decreased if Na2CO3 was added. If low concentration Na2CO3 was added, Zn bound to organic matters and residual would increase in content but would lower if high concentration one was added. [Conclusion] The research provided references for measurement of heavy metal ion content in soil in different places.

Amelioration of Saline-Sodic Soils with Tillage Implements and Sulfuric Acid Application

Amelioration of saline-sodic soils through land preparation with three tillage implements （disc plow, rotavator and cultivator） each followed by application of sulfuric acid at 20% of gypsum （CaSO4-2H2O） requirement or no sulfuric acid application during crop growth period was evaluated in a field study for 2.5 years at three sites, i.e., Jhottianwala, Gabrika （Thabal）, and Thatta Langar, in Tehsil Pindi Bhattian, Hafizahad District, Pakistan. Within 2.5 years, there was a decrease in the salinity parameters measured （electrical conductivity, pH, and sodium adsorption ratio）, with a gradual increase in rice and wheat grain yields. It was observed that the disc plow, which not only ensured favorable yields but also helped improve soil health at all the three sites, was the most effective tillage implement. Also, application of sulfuric acid resulted in higher yields and promoted rapid amelioration of the saline-sodic soils.

Effect of Irrigation Water Quality on Soil Hydraulic Conductivity

The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m^-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m^-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.

Experimental study on dispersive soil in western Jilin

In order to research engineering geological properties of the soil in Zhenlai of western Jilin, especially the dispersivity of soil, the authors carried out the basic physicocbemical test and dispersivity identification test. The results show that the dispersivity of the soil increases with the increase of depth within 0-30 cm （surface soil） ; it decreases as the depth increases within in 30-100 cm. Furthermore, the statistical analysis of the dispersivity indexes and physicochemical propertity indexes show that the DP is positively linear correlated with total soluble salt content, sodium ion content, ESP, pH and organic matter content. Meanwhile, it is negatively linear correlated with clay content, and the linear relationship is better. Through the study of the dispersion mechanism of soil samples, it can be concluded that sodium montmorillonite, higher percentage of exchangeable sodium and high pH are the main reasons for the dispersion of soils in western Jilin.

Adsorption of Potassium and Sodium Ions by Variable Charge Soils

Adsorption of potassium and sodium ions by four typical variable charge soils of South China was studied. The results indicated that the variable charge soils saturated with H and Al showed a much higher preference for potassium ions relative to sodium ions, and this tendency could not be changed by such factors as the pH, the concentration of the cations, the dielectric constant of solvent, the accompanying anions and the iron oxide content etc., suggesting that this difference in affinity is caused by the difference in the nature of the two cations. It was observed that a negative adsorption of sodium ions by latosol and lateritic red soil in a mixed system containing equal amount of potassium and sodium ions at low pH, which is caused by a competitive adsorption of potassium and sodium ions and repulsion of positive charge on the surfaces of soil particles for cations. The adsorption of potassium and sodium ions increased with the decreases in the dielectric constant of solvent and the iron oxide content. Sulfate affected the adsorption of potassium and sodium ions through changing the surface properties of the soils.

Calcareous Sodic Soil Reclamation as Affected by Corn Stalk Application and Incubation: A Laboratory Study

A laboratory lysimeter experiment was conducted to investigate the effects of forage corn （Zea rncbys L.） stalk application on the CO2 concentration in soil air and calcareous sodic soil reclamation. The experimental treatments tested were soil exchangeable sodium percentage （ESP） levels of 1, 11, and 19, added corn stalk contents of 0 to 36 g kg^-1, and incubation durations of 30 and 60 days. The experimental results indicated that corn stalk application and incubation significantly increased CO2 partial pressure in soil profile and lowered pH value in soil solution, subsequently increased native CaCO3 mineral dissolution and electrolyte concentration of soil solution, and finally significantly contributed to reduction on soil sodicity level. The reclamation efficiency of calcareous sodic soils increased with the added corn stalk. When corn stalks were added at the rates of 22 and 34 g kg^-1 into the soil with initial ESP of 19, its ESP value was decreased by 56% and 78%, respectively, after incubation of 60 days and the leaching of 6.5 pore volumes （about 48 L of percolation water） with distilled water. Therefore, crop stalk application and incubation could be used as a choice to reclaim moderate calcareous sodic soils or as a supplement of phytoremediation to improve reclamation efficiency.

Effects of Humic Acid and Solution Ph on Dispersion of Na-and Ca-Soil Clays

Dispersed soil clays have a negative impact on soil structure and contribute to soil erosion and contaminant movement. In this study, two typical soils from the south of China were chosen for investigating roles of pH and humic acid (HA) on dispersion of soil clays. Critical flocculation concentration (CFC) of the soil clay suspension was determined by using light transmission at a wavelength of 600 um. The results indicated that effects of pH and HA on dispersion of the soil clays were closely related to the type of the major minerals making up the soil and to the valence of the exchangeable canons as well. At four rates of pH(4, 6, 8 and 10), the CFC for the Na-yellow-brown soil treated with H2O2 was increased from 0.32 to 0.56, 6.0 to 14.0,10.0 to 24.6 and 26.0 to 52.0 mmol L-1 NaCl, respectively when Na-HA was added at the rate of from 0 to 40 mg L-1. With the same Na-HA addition and three pH (6, 8 and 10) treatments, the CFC for the Na-red soil was increased from 0.5 to 20.0, 1.0 to 40.0 and 6.0 to 141.0 mmol L-1 NaCl, respectively. Obviously,pH and HA has greater effects on clay dispersion of the red soil(dominated by 1:1 minerals and oxides)than on that of the yellow-brown soil(dominated by 2: 1 minerals). However, at three rates of pH (6, 8 and 10) and with the addition of Ca-HA from 0 to 40 mg L-1, the CFC of the Ca-yellow-brown soil and Ca-red soil treated with H2O2 was increased from 0.55 to 0.81, 0.75 to 1.28, 0.55 to 1.45 and 0.038 to 0.266, 0.25 to 0.62, 0.7 to 1.6 mmol CaCl2 L-1, respectively. So, Na-soil clays are more sensitive to pH and HA than Ca-soil clays.

Factors Affecting Diffusion of Ions in Soils

In this work the diffusion coefficients of Na+, K+, Ca2+, NO3- and Cl- ions were estimated in terms of measuring apparent direct current (DC) conductivities of latosol, red soil and yellow-brown earth containing, respectively, NaNO3, KCI, and CaCl2 of different concentrations (0.005, 0.05, 0.10, and 0.15 mol / L) in the case of moisture contents ranging from wet to water saturation. The results showed that when bulk density, moisture content, and electrolyte concentration were constant, the diffusion coefficients of cations were in the order Na+> K+> Ca2+ except for Na+ and K+ in latosol, while the order for anions was NO3- > Cl-. The diffusion coefficients (Di) of cations and anions were linearly proportional to volumetric moisture content (θ) as electrolyte concentration and bulk density were unchanged. When moisture content and bulk density were constant, the diffusion coefficients of cations decreased, to varying extents, with the increase of electrolyte concentration, and the decrement in different soils followed the order yellow-brown earth > red soil > latosol, but the decrement order of different cations was Na+> K+ > Ca2+.

Some Physiological Responses of Chinese Iris to Salt Stress

Chinese iris （Iris lactea Pall. var. chinensis （Fisch） Koidz.）, a robust iridaceous plant, is widespread in arid and semiarid regions with high salinity. However, the mechanism of its salt tolerance is not well understood. In this study, plant growth, water status, content and distribution of inorganic ions, cell membrane permeability, and proline content of I. laetea under salt stress were investigated using nutrient solutions with six NaCl concentrations ranging from 0 to 350 mmol L^-1. The results indicated that the biomass, height, fresh weight, K^＋ content, and K^＋/Na^＋ and Ca^2＋/Na^＋ ratios decreased with increasing NaCl stress, whereas plant water deficit and contents of Na^＋ and Cl- increased with increasing NaCl stress. In all salt treatments, water deficit of shoots was found to be higher than that of roots and had a positive correlation with salt concentration. When the NaCl concentration was less than 280 mmol L^-1, the ion absorption selectivity ratio and the transportation selectivity ratio sharply increased with increasing NaCl stress. Under medium salt stress, I. lactea exhibited a strong K^＋ selective absorption and the transportation of K^＋ from roots to shoots increased, whereas Na^＋ was not transported and was mostly retained in roots. The plants were able to maintain osmotic adjustment through the accumulation of Na^＋, Cl-, and proline. On the basis of its biomass production under salt stress, I. lactea could be considered as a facultative halophyte.

Improvement of Soil Fertility and Crop Yield through Biochar Amendment from Salt Affected Soil of Central China

Soil salinity has been considered a brutal environmental factor for decreasing crop yield due to the accumulation of excessive sodium salts in soil under arid and semi-arid region of the world. This study tries to address the potential use of biochar. An organic matter rich material, used to reclaim salt-stressed soil in order to enhance crop production in dry croplands as well as to increase soil organic carbon （SOC） and to improve soil fertility. In this regard, a field experiment for two years was conducted in a moderately salt-stressed soil of Central China with wheat-maize cropping system. The soil was amended with biochar composted with poultry manure （BPC） at 12 t/ha with diluted pyroligneous solution （PS） at 0.15 t/ha a week before sowing of crop. Results showed significant improvement in soil physical properties, soil nutrient content with reduction of sodium salts and soil pH by amendment of BPC-PS1 and BPC-PS2 over the experimental control salt-stressed cropland. Furthermore, wheat and maize grain yield, nitrogen, phosphorous potassium and K/Na ratio increased while sodium decreased with the application of BPC-PS amendment in wheat and maize grain. This study concluded that the biochar amendment in conjunction with PS greatly improved SOC storage, crop nutrient uptake and soil fertility. Thus, waste treatment of crop straw and poultry manure compost as biochar could be combined to alleviate salt stress and improve crop production in the vast area of arid and semi-arid regions of the world.

Preparative Parameter Effects on Synthesis of Birnessite by O_2 Oxidation

Birnessite occurs in a wide variety of natural environments, and plays animportant role in soil chemistry. A modified Staehli procedure was used to synthesize sodiumbirnessite in an alkali medium by O_2 oxidation. The effects of preparative parameters on thesynthesis of birnessite, such as pretreatment on solutions with N2, reaction temperature, O_2 flowrate, fluxion velocity of the reaction suspension, and dehydration conditions were investigated. Thefluxion velocity of the reactive suspension and O_2 flow rate significantly influenced thesynthesis of birnessite. Vigorous stirring raised the fluxion velocity of the reaction suspensionand easily allowed synthesis of pure crystalline birnessite. However pretreatment of the reactingsolutions with N_2 and the reaction temperature had little effect on the synthesis. Diffusion of O_2was the controlling step during the course of oxidation. The optimum synthetic conditions for purebirnessite were: a NaOH to Mn molar ratio of 13.7, an O_2 flow rate of 2 L min^(-1), and oxidationfor 5 hours with vigorous stirring at normal temperatures. The chemical composition of thesynthesized pure birnessite was Na_(0.25)MnO_(2.07)·0.66H_2O.

Application of NaHCO_3/ DTPA Extractant-ICP Spectrometry Technique in Soil Test for Availability of Nutrients and Heavy Metals

Soil test for availability of nutrients and heavy metals is extensively served as a means for the evaluations of soil fertility, and environmental effects and phytotoxicity of pollutants in soils, and for the fertilizer recommendation in agricultural and environmental sciences. Therefore, great attention has been paid to the measurement of elemental availability in soil test.