Chemistry of groundwater of Al-Ahsa Oasis eastern region Saudi Arabia and its predictive effects on soil properties

Saudi Arabia is an arid and the largest country in the middle east with a total land area of 2.253 x 10(6) km2. Recent urban and rural expansion has shown manifold increases in water use in various sectors. Water resources are limited and non-renewable coupled with unpredicted scanty rainfall. In order to meet the rising water needs, evaluation of water quality is important for allocation to various uses. A total of 101 well water samples were collected from Al-Ahsa Oasis. Water samples were analyzed for total salt concentration, pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, F and B contents. Soil Salinity Development (SSD), adjusted sodium adsorption ratio (adj.SAR), adjusted sodium adsorption ratio (adj. R(Na)) and Exchangeable Sodium Percentage (ESP) were calculated. The EC of groundwater ranged between 1.23 and 5.05 dS m(-1). Sodium was the most abundant cation followed by Ca, Mg and K in descending order. Chloride was the most abundant anion followed by SO4 and HCO3 in groundwater of Al-Ahsa Oasis. A significant correlation was found between Na and Cl (R2 = 0.936). Thermodynamics calculation revealed that an appreciable amount of Ca and Mg is associated with Cl and SO4 ions. The SAR and ESP values are within the permissible limits according to Ayers and Westcot, 1985. The NO3 concentration is within safe limits for drinking purpose according to WHO (1998) standards. The Saturation Indices (SI) indicated that groundwater is under-saturated (negative SI) with respect to certain minerals (for example: calcite, dolomite, gypsum, anhydrite, halite, pyrite, fluorite and aragonite) and oversaturated (positive SI) with respect to some other minerals (For example: Goethite, Siderite and hematite). The negative saturation index (SI) reveals that most of minerals are in un-saturated state and will dissolve more Ca and Mg into the soil solution after irrigation. A good relationship exists between Cl and other ions (Na, Ca and Mg) as well as between SO4 and Ca and Mg ion of groundwater. The salinity and sodicity hazards of groundwater of Al-Ahsa Oasis were classified as C3S1 and C4S2 i.e., high salinity with medium sodicity problems. The predicted soil salinity suggested application of 15-20% leaching requirements to keep soil salinity within permissible limits. Cultivation of slight to moderate salt and sodium tolerant crops is recommended for optimal agricultural production and efficient water use.     

盐碱混合胁迫对小麦幼苗阳离子吸收和分配的影响

为探讨盐碱胁迫下小麦阳离子吸收和分配特点,采用两种中性盐（NaCl和Na₂SO₄）和两种碱性盐（NaHCO₃和Na₂CO₃）混合模拟不同浓度盐碱胁迫条件,对龙麦26和克旱16两种不同基因型春小麦幼苗进行14 d胁迫处理,测定和分析了叶片和根系中Na⁺、K⁺、Ca²⁺、Mg²⁺含量的变化。结果表明,盐碱混合胁迫增加了小麦幼苗Na⁺含量,且随着盐浓度的增加和碱性盐比例的提高,Na⁺含量逐渐增加;龙麦26幼苗K⁺的吸收规律与Na⁺相同,而克旱16幼苗K⁺含量变化与之相反;盐碱混合胁迫通过降低植株的K/Na限制了Ca²⁺、Mg²⁺的吸收量,且阻碍了Ca²⁺、Mg²⁺由根向地上部的运转,致使叶片中Ca²⁺、Mg²⁺含量降低。盐碱混合胁迫下,小麦对Na⁺、K⁺等一价阳离子与Ca²⁺、Mg²⁺等二价阳离子的吸收上表现为拮抗作用。     

The effect of waterlogging on electrochemical properties and soluble nutrients in paddy soils

This study was conducted to investigate the influence of waterlogging on availability of nutrients in paddy soils. The five soils were incubated under a waterlogged condition at 30 °C for 12 weeks. The EC, Eh, pH, NH₄, K, Na, Ca, Mg, Cl, P, Fe, and Mn of soil solutions were monitored over the waterlogged period. The Eh values generally dropped to the lowest point within 14 days of waterlogging, then increased, and reached equilibrium after 8 weeks of waterlogging. The soil pH decreased in the first 2–4 weeks of waterlogging. The EC values increased partly due to dissolution of soluble salts in the first 2 weeks. The concentrations of soluble NH₄ were significantly increased with waterlogging, reached maximum values at week 4–6, and then declined to the initial level. Waterlogging increased the concentration of soluble K, Ca, Mg, Fe, and Mn ions, the magnitudes of changes were greatly affected by soil properties. Increases in soluble Na, K, Ca, and Mg were attributed to the increase in solubility of insoluble salts and increase in competition for the exchange sites. Increases in soluble Fe and Mn induced by waterlogging were attributed to the dissolution of Fe and Mn oxides under reduced conditions.     

钙离子对绿茶浸提茶汤理化与感官品质的影响

研究了含不同质量浓度钙离子（0~100mg/L）的水对绿茶浸提茶汤的理化成分及感官品质的影响。研究结果表明,随着钙离子质量浓度的升高,浸提茶汤浊度增加,pH值下降;总固形物和氨基酸含量呈增加趋势,茶多酚和蛋白质含量呈下降趋势,而咖啡碱和黄酮化合物含量差异不显著;儿茶素EGC含量呈增加趋势,C、EGCG、GCG、ECG及CG含量都呈下降趋势,EC含量差异不显著;Al³⁺、Cu²⁺、Na⁺、Zn²⁺含量呈下降趋势,而K⁺、Mg²⁺、Mn²⁺含量呈增加趋势;茶汤感官品质下降,逐渐变浑浊,熟闷味加重,苦涩味增加。钙离子主要通过参与冷后浑形成、诱导儿茶素组分异构化及氧化分解反应等作用影响茶汤品质。     

Hydrochemical processes and metal composition of Ain Umm-Sabah natural spring in Al-Hassa Oasis Eastern Province, Saudi Arabia

This study was carried out to determine the hydro-chemical processes and the metal concentration of spring water to evaluate its suitability for irrigation and other purposes. A total of 10 water samples were collected from Ain Umm Sabah at different times and from different locations from the spring basin. EC (dS m(-1)), pH, temperature, total cations (Na, Ca, Mg, K) and anions [Cl, CO3, HCO3, SO4, NO3, Fluoride (F)] were determined. Some trace and heavy metals (Al, As, Ba, B, Br, Mo, Ni, Si, Cd, Cu, V, Fe, I, Pb, Mn, Zn, Sr, Se, Sb, La and Se were determined. The Spring water is classified as C4S2 (high salinity with medium sodicity problem water). Chloride (Cl) and nitrate (NO3) concentrations were higher than the permissible limits according to World Health Organization Standards. The Ain Umm Sabah water is Na-Cl dominant water and can create soil sodicity problems and cause Na and Cl ion toxicity to plants if used for irrigation of sensitive crops. The spring water is under-saturated (negative SI) with respect to calcite, dolomite, gypsum, anhydrite, halite, fluorite and aragonite and oversaturated (positive SI) with respect to goethite, siderite and hematite minerals. The concentration of all the estimated trace metals was within the permissible limits for its use as drinking water and other purposes according to WHO. Since the spring water contains high concentration of NO3, hence can not be used for drinking purposes without prior treatment. The study findings suggest careful use and pumping of water from the spring. Further studies are required on regular basis to monitor the depletion in the spring water level and the temporal change in water salinity.     

人心果在NaCl胁迫下的离子效应及耐盐方式

为了研究人心果在NaCl胁迫下的离子效应及耐盐方式,本试验测定了人心果根、枝条、叶在NaCl胁迫下Cl-、Na+、K+、Ca2+的含量及分布特点.结果表明,人心果根、枝条、叶的Cl-、Na+、Ca2+含量随处理浓度升高而升高,K+、K+/Na+随处理浓度升高而降低.在8‰处理浓度时,根、枝条、叶的Cl-含量分别为对照的8.94、6.77、4.49倍,Na+含量分别为对照的2.16、2.88、2.45倍,K+/Na+分别为0.13、0.43、0.35.相同处理浓度下,根的Cl-、Na+含量均最高,含量高低顺序如下:Cl-:枝条＜叶＜根;Na+:叶＜枝条＜根;K+:根＜叶＜枝条;Ca2+:根＜枝条＜叶.研究结果表明:Cl-、Na+进入植物体后,较大部分滞留在根部,人心果具有根系截留效应,推测其抗性方式为避盐性,研究结果还推测人心果的盐害和细胞Ca2+的自动动态平衡遭到破坏有关.     

茶树根际土壤性质及氮肥的影响

本文报导了对盆栽茶树根际土壤性质的研究结果。经外力抖落后仍粘在根系上的土壤作为根际土壤,其余土壤为非根际土壤。施氮显著降低土壤pH、交换性K、Ca、Mg含量和盐基饱和度,增加水溶性铝、有机交换态铝和吸附羟基态铝的含量。与非根际土壤相比,根际土壤pH、交换性Ca、Mg和盐基饱和度明显降低,而交换性K高于非根际土壤。根际土壤的水溶性铝、交换性铝、交换性铝饱和度和吸附羟基态铝的含量显著高于非根际土。上述结果说明茶树根际土壤明显酸化,增强了土壤铝有效度。铝在茶树根际微域环境中的这种变化,可能在茶树吸收铝的过程中起着重要作用。     

尿素和茶树落叶对荒地土壤元素迁移的影响

用亚热带茶区的3 种未垦荒地土壤进行土柱模拟, 研究重施尿素和表覆茶树落叶对土壤中Si、Al、K、Na、Ca、Mg 等6 种元素迁移的影响。结果表明, Si 的淋出量和Al+ K+ Na + Ca +Mg 的淋出总量均以黄棕壤> 红壤> 赤红壤。尿素和茶树落叶处理对硅淋出量的影响较小, 但可使各土壤主要的淋失元素, 包括赤红壤中的Ca 和Na, 红壤中的Ca 和Al 及黄棕壤中的Na、Ca和Mg 的淋失量明显增大, 从而使Al+ K+ Na+ Ca+ Mg 的淋出总量在3 种土壤中分别比对照柱增加163 % 和58% 、64 % 和57 % 、140 % 和84 % , 尿素的促进盐基和Al 淋失作用比茶树落叶更强,两者都可加速土壤的酸化。     

槟榔色素稳定性的研究

本试验研究槟榔色素的稳定性。结果表明:槟榔色素对热稳定性较好但对光稳定性较差;在酸性条件下稳定;对常用的防腐剂山梨酸钾、苯甲酸钠、柠檬酸等稳定;氧化剂和还原剂对色素的稳定性有影响,色素对低浓度VC稳定性好,在H2O2中稳定性差;金属离子Cu2+、Mg2+、Ca2+、K+、Na+、Zn2+对色素的稳定性影响较小,但Fe2+、Fe3+对色素的稳定性有显著的影响。     

不同工艺制备火龙果粉中红色素稳定性的研究

为增加火龙果中天然红色素的稳定性，实现其在食品加工中的应用，以红肉火龙果果肉为原料，研究pH值、金属离子、甜味剂、食品添加剂等因子对其喷雾干燥粉、冻干原粉及冻干包埋粉中红色素稳定性的影响。结果表明：该火龙果粉中色素对高温敏感，喷雾干燥粉中的色素损失率高于冻干原粉和冻干包埋粉；色素在pH6的环境中较稳定；Ca2+、K+、Mg2+对色素稳定性影响不大，Na+有利于提高喷雾干燥粉中色素的稳定性，Zn2+、Al3+不利于色素热稳定性，Fe3+、Cu2+可对果粉中的色素稳定性造成严重损坏；甜味剂等碳水化合物对火龙果粉中色素稳定性无不利影响；丙酸钙不利于色素稳定，过氧化氢明显降低喷雾干燥粉热处理后的色素残留率，亚硫酸钠对3种果粉的色素均可造成严重破坏，抗坏血酸可明显提高3种果粉色素的热稳定性。该结果为促进火龙果粉的加工及利用提供一定的参考价值。     

STUDIES IN RESPONSE TO NITROGEN

Data are presented demonstrating the effects of applying fertilizer N at 59, 118 or 177 kg/ha on 16 Apr. on uptake of K, P. Ca, Mg and Na in primary growth (PG) harvested 8, 12, 16, 23, 29, 45 and 57 days afterwards, and residual effects in two successive regrowths (RG1 and RG2) harvested on 12 June and 13 Aug., respectively. Significant residual responses as uptake of K, P, Ca, Mg and Na were shown in RG1 and RG2 after all dates of harvesting PG. The residual responses compensated for poor uptake in PG. Thus, low uptakes to the second increment of N were followed by high residual responses in both regrowths; and low uptakes in PG harvested shortly after applying the fertilizer N were followed by high residual responses. Averaged over the seven dates of PG harvest, the sum of responses (PG+RG1+RG2) to the second N increment was greater than total response to the first increment in P and Mg, considerably greater in Ca and Na and slightly lower in K. These marked residual responses to the second N increment were most noticeable where PG was harvested 23 days after applying fertilizer N and became less marked as date of PG harvest was advanced. Percentage K, P, Ca, Mg and Na in DM of the PG and of RG1 increased as N application was raised. By RG2, the residual effects of fertilizer N on percentage K. P and Mg were reversed to give reduced percentages with increased N application to PG. indicative of deficiencies in availability of these elements. The application of 177 kg N/ha to PG resulted in the release of additional soil N and of other mineral elements which could lead to their depletion.     

Sodium fertilizer application to pasture. 4. Effects on mineral uptake and the sodium and potassium status of steers

Mineral availability and status in body tissues was examined with four rumen-fistulated steers arranged in a Latin-square change-over design. The steers were fed perennial ryegrass herbage from a pasture fertilized with four Na treatments: 0 (Nil), 32 (Low), 66 (Medium) or 96 (High) kg Na ha^-1 yr^-1. Na fertilizer increased herbage contents and intakes of Na, Mg and Ca but did not affect intakes of K, P and S. Herbage K:Na and K:(Ca+Mg) decreased in direct proportion to the amount of Na fertilizer applied. With increasing dietary Na intake, the Na content of saliva increased and the K content decreased. There was an increase in Na and a reciprocal decrease in K contents of rumen fluid with increasing dietary Na. Blood plasma Na contents were greater when the Na-treated herbages were fed than in the Nil treatment. There was no effect of treatment on blood plasma K content. Increasing dietary Na increased urinary Na but did not affect urinary K. Faecal mineral concentrations of Na, Ca, P and S were increased by increasing dietary Na, whereas K content was reduced and the Mg content was unaffected. There was no difference between treatments in the proportion of mineral rapidly solubilized, except Na which increased with increasing dietary Na content. The fractional rate of degradation was greater for Na, K, and Mg than for Ca and P. Based on effective solubilization, minerals were ranked in the order K > (Mg = Na) > Ca > P, and treatments were in the order Medium > (High = Low) > Nil. Increasing Na intake increased Ca but not P or Mg availability and increased the uptake of all three minerals.     

盐胁迫下野生大豆叶片中Na+、Cl-积累导致活性氧伤害

以耐盐性强弱不同的野生大豆(JWS耐盐性强，N23232耐盐性弱)为材料，采用砂培试验研究了NaCl胁迫下野生大豆叶片中Na^ 、Cl^-含量及活性氧代谢的变化。结果表明，盐胁迫下供试两种群野生大豆叶片Na^ 、Cl^-含量增加，N23232比JWS更明显；耐盐性弱的N23232叶片O2^-产生速率和H2O2含量上升，膜脂过氧化产物MDA和电导率迅速上升，其叶片中Na^ 、Cl^-含量变化与O2^-、H2O2、MDA和电导率增加呈极显著或显著正相关，而O2^-产生速率和H2O2含量上升与MDA和电导率变化呈极显著正相关。表明在NaCl胁迫下，由于Na^ 、Cl^-在叶片中的积累而导致了活性氧的积累，活性氧诱发膜脂过氧化、破坏膜结构，导致膜结合酶H^ -ATPase和H^ -PPase活性降低，膜透性增加。耐盐种群JWS在盐胁迫下Na^ 、Cl^-积累量少、活性氧水平较低，对膜系统伤害少，膜结合酶活性高，因而能维持液泡膜正常的代谢功能，可能是其耐盐性强的原因之一。     

Sodium fertilizer application to pasture. 5. Effects on herbage digestibility and mineral availability in sheep

The effects of feeding herbages fertilized with 0 (nil), 32 (low), 66 (medium) or 96 (high) kg of sodium per hectare per year to sheep on herbage digestibility and mineral availability were examined. Modified acid detergent fibre (MADF), ash, magnesium (Mg) and phosphorus (P) contents were increased by the application of sodium (Na) treatments, while potassium (K), sulphur (S) and true protein (TP) contents were reduced. Dry matter (DM) and MADF intakes were increased in the low and medium treatments and DM and MADF digestibility increased in all Na-treated herbages. The medium- and high-sodium treatments increased salivary Na content and Na/K ratio and decreased K content. Blood K content was not affected by treatment. Intake, faecal output, apparent availability, urinary output and balance of Na were increased by the application of Na treatments. Potassium intake, balance, apparent retention and urinary output were increased by the low, unaffected by the medium and reduced by the high sodium treatment. The low and medium Na treatments increased the intake and apparent availability of Mg; Mg balance and apparent retention were increased by all Na treatments. Feeding the Na-treated herbages increased intakes, apparent availability, balance and apparent retention of Ca, P and total cations.
The low and medium Na treatments increased S intake, faecal output and apparent retention. It is suggested that through increasing the balance and apparent retention of minerals, the application of sodium fertilizer to pasture will improve the mineral status of sheep, particularly at the low and medium application rates employed in this experiment.     

Response of permanent and reseeded grassland to fertilizer nitrogen. 2. Effects on concentrations of Ca, Mg, K, Na, S, P, Mn, Zn, Cu, Co and Mo in herbage at a range of sites

The concentration of mineral elements in herbage from permanent swards of mixed species composition (predominantly Agrostis spp., Holcus lanatus, Festuca rubra, Lolium perenne, Poa spp., etc.) was compared with that from sown perennial ryegrass ( Lolium perenne ) at two fertilizer rates (0 and 300kg N ha⁻¹ year⁻¹, both with P and K) and with L. perennel Trifolium repens (at 0 N with P and K). The investigation was conducted over four years at sixteen contrasting sites in England and Wales. Herbage samples for mineral analysis were taken at first and fourth harvests (May and August) each year from plots under 4-weekly cutting. There was a wide degree of variation between sites, particularly for concentrations of Ca, Mg, Na and all trace elements analysed. Herbage from L. perenne reseeds had significantly higher concentrations of Ca, Mg, Na, Co and S, but K, Mo, Zn, Cu and P were generally lower than in the permanent swards. L. perennel T. repens swards had the highest concentration of major cations, but trace element levels were generally intermediate between those for 0 N permanent and L. perenne swards. Fertilizer N reduced concentrations of Ca, Mn, Mo and S, and increased Mg, Na and Zn, with no consistent effects on K, Co and Cu. Herbage at harvest 4, compared with harvest 1, had higher Ca, Mg, Na, Mn, Zn and S. Permanent and L. perenne swards responded similarly to fertilizer N and between harvest dates. Results are discussed in relation to previous reports of botanical and fertilizer effects on mineral concentrations, and the mineral requirements of livestock. Changes in mineral concentration resulting from reseeding permanent swards are considered unlikely to increase mineral-related livestock disorders, and in many cases could be beneficial, though problems might arise on sites where some elements, e.g. Cu and Mg, are low.     

转GmGT-2B基因大豆的耐盐性分析

采用盆栽试验方法,苗期在盐胁迫条件下,比较GmGT-2B转基因大豆与非转基因大豆的损伤程度、超氧化物歧化酶(SOD)活性,丙二醛(MDA)、脯氨酸和K~+、Na~+含量以及基因表达量变化差异。结果表明:盐胁迫对转基因大豆叶片的伤害程度明显低于对照;SOD活性、脯氨酸含量、丙二醛(MDA)含量在盐胁迫5 d后均与对照有显著或极显著差异;植株的Na~+含量随盐胁迫时间的增加而升高,在胁迫第8天转基因大豆的Na~+含量达到对照约2倍;转基因大豆的基因的表达量呈上调趋势,在第8天达到表达高峰。基因表达量的变化趋势与生理指标SOD活性、脯氨酸含量和Na~+含量表现的一致。结果表明GmGT-2B基因与盐应答反应有关,其中转GmGT-2B大豆株系N11和N24盐害程度较低,该基因和转GmGT-2B基因大豆具有较大的应用价值。     

铜与锌对茶树生育特性及生理代谢的影响Ⅲ．施铜对茶树体内铜及其他矿质元素吸收的影响

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盐胁迫对香蕉幼苗体内Na＋和K＋含量及其分布的影响

采用营养液栽培,以香蕉幼苗为试材,研究了盐胁迫对香蕉幼苗根部、假茎和叶片各部位Na+和K+含量以及K+/Na+的影响。结果表明,与对照相比植株体内Na+的含量增加,而植物体内K+含量减少,K+/Na+下降显著。     

The distribution and coexistence of some wild plants in relation to mineral nutrient availability in a high sodium polluted site in central Sudan

The factors affecting the distribution and coexistence of Cyperus laevigatus, Typha angustata and Paspalum viginatum, in a high sodium polluted site in central Sudan, were investigated. The high sodium content of the site was mainly due to effluents from a near by textile factory where high quantities of Na compounds, like: NaOH, Na2CO3, Na2SiO3 and NaHCO3 were used in the textile processes. The investigation was carried out by chemical analysis of soil and plant samples and computation of correlation coefficients between soil nutrients and ion uptake by the investigated plants. Soil and plant samples, from the investigated site, were collected from 35 sampling points of 80 x 120 m rectangular grid, each point is 20 m distant from the other neighboring points. Soil chemical analysis data showed that the investigated site was moderately alkaline and characterized by very high content of Na, reasonably high content of Ca, adequate quantities of Mg, K and Fe, low content of NH4-N and P and very low content of Mn. The plant chemical analysis results clearly reflect the different nutritional requirements of the examined plant species. Correlation analysis between soil nutrients and ion uptake by the investigated plants showed that the uptake of a mineral ion by any of the three investigated plant species may be accelerated, slowed down, or may have no obvious effect by another ion in the soil. Moreover, correlation and regression analysis clearly reflect the different patterns of mineral nutrient uptake by the investigated species and hence niche differentiation and coexistence between the investigated species in the investigated site.     

萌发期低盐对4份玉米自交系的影响

利用不同浓度Na Cl、Na2SO4的低盐,对郑58、DK516♀、DK516♂和昌7-2四份玉米自交系萌发期进行胁迫处理,研究低盐胁迫对4份自交系的影响。结果表明:胚芽长度、胚芽鲜重、胚芽干重、发芽指数和活力指数均随盐浓度的加大呈现先增加后降低的趋势,部分盐浓度间存在显著性差异;萌发期耐盐性综合表现为DK516♀、昌7-2较优,DK516♂次之,郑58表现较差。昌7-2和DK516♂根系相对发达,初步推断DK516♂和昌7-2抗倒伏能力相对较好,但有待大田试验进一步验证。