Characteristics of Copper Sorption by Various Agricultural Soils in China and the Effect of Exogenic Dissolved Organic Matter on the Sorption

To explore the effect of exogenic dissolved organic matter (DOM) on Cu(II) sorption in agricultural soils, 26 agricultural soils were collected across China. Exogenic dissolved organic matter, extracting from wheat straw (DOM_W) and swine manure (DOM_S), respectively, were added to the soils to conduct a series of batch sorption and characterization experiments. The solid-liquid partition coefficient (K_d) ranged from 0.02 to 76.46 L g^?1, suggesting different Cu(II) sorption on various soils. PCA analysis indicated that pH, free Fe/Al oxides, carbon, and total Cu content had a significant positive relationship with the Cu(II) sorption, respectively. And the contribution rate of pH was the highest (38.15%). Moreover, DOM markedly inhibited the Cu(II) sorption in alkaline soils while promoted the Cu(II) sorption in acidic soils, which were interacted by the soil properties and DOM characteristics. The effect of DOM_S on Cu(II) sorption were more obvious than DOM_W, which were further confirmed by Fourier transform infrared (FTIR) spectroscopy. FTIR also showed Cu(II) was primarily adsorbed on the specific functional groups, such as CO, OH, and CO, providing direct evidences for the binding of Cu(II) with DOM. This study can guide the rational use of organic fertilizers, and also provide baseline knowledge for the prevention and control of soil pollution.     

Sorption Behavior of Cesium in Two Greek Soils: Effects of Cs Initial Concentration,Clay Mineralogy,and Particle-size Fraction

The characteristics of Cs sorption behavior in two soils (soil 1 and soil 2) with nearly the same clay content and exhangeable K concentration, but with different clay mineralogy, were studied by the quantification of the distribution coefficient (k_d). It was observed that as the initial Cs concentration increased from 4 to 50 mg L^?1, the k_d values decreased in both soils, suggesting a progressive saturation of Cs available sorption sites. However, the presence of expansible 2:1 phyllosilicates minerals in the clay fraction of soil 2 maintained a high Cs sorption ability for this soil, even at high Cs concentrations. The experimental data were also fitted to the Freundlich isotherm and the results showed that parameters of the Freundlich equation could be used to estimate the degree of Cs sorption and the nature of the available sorption sites. For the studied soils, the k_f and the k_d values followed a similar trend and the n Freundlich constant values provided a reliable indicator for the soils’ clay mineralogy. The removal of the sand fraction enhanced Cs sorption in both soils and the absence of sorbed Cs ions on the quartz minerals, as observed by the SEM analysis, additionally supported the effect of particle-size fraction on Cs sorption.     

黑河下游额济纳绿洲植物群落特征与物种多样性研究

根据53个20 m×20 m样方调查资料,对黑河下游额济纳绿洲植物群落特征及物种多样性进行研究.结果表明:(1)调查样方的植物种类组成成分简单,科属组成较为分散.共有12科26属28种,以藜科、菊科为主,分别占21.43%和14.29%.种类优势现象明显,重要值>10的物种主要有胡杨、梭梭、柽柳、白刺、沙拐枣、苦豆子等;(2)不同植物群落类型的物种多样性指数均较低,且存在较大差异.以重要值计算的Margalef丰富度指数(Rm)介于0.027 3~0.567 7,Simpson多样性指数(Ds)介于0.677 8~0.999 3,Shannon-Weiner多样性指数(H′)介于0.098 2~0.367 3,Pielou均匀度指数(J′)在0.078~0.383之间,表明荒漠绿洲植物群落的结构简单、组织水平低;(3)样方统计的物种多样性指数纬向变化没有经向变化趋势明显,Ds和H′的纬向变化在42.02°N附近存在一个明显的高值区,经向变化呈先增后减的趋势,J′纬向变化与Ds和H′变化趋势较为一致,经向变化趋势不明显,呈连续波动的复杂变化特征.     

黑河中游土地利用转型过程及其对区域生态质量的影响

干旱区土地利用转型作为影响区域生态系统变化的主要因素,直接关系人类福祉.本文以生态脆弱的黑河中游地区为研究对象,基于1987、2001、2016年的遥感影像数据,采用土地利用转型检测评估模型、生态响应模型系统研究了1987—2016年黑河中游地区土地利用转型的过程及其区域生态质量响应规律.结果表明: 1987—2016年,研究区土地利用转型变化显著,总变化量呈增加趋势,耕地和建设用地持续增加;在随机新增和减少状态下,未利用地向其他地类转型的倾向性不强,草地向耕地转型具有很强的倾向性;研究区生态质量总体呈下降趋势,生态用地呈缩减态势,净减少2.8%,对于生态环境退化影响最大的土地利用转型类型是草地向耕地和未利用地的转型.为促进区域土地资源的可持续利用以及改善区域生态质量状况,需根据区域水资源状况合理分配区域生产用地和生态用地的比例.     

黑河流域景观结构分析

在黑河流域土地利用分类的基础上,利用地理信息系统进行流域景观制图,划分出6个景观区。利用景观结构分析软件FRAGSTATS在流域尺度上计算了各景观区的多种景观结构指标。结果表明：山区的景观结构特征突出表现为连通性强,拼块形状复杂。绿洲－荒漠区的景观结构特征表现为,绿洲主要沿河流和渠道分布,是镶嵌在荒漠基质上的景观异质体。绿洲是干旱区景观结构最复杂,类型最丰富,景观多样性最高的地区,但不同景观区的绿洲其景观结构有显著的差异。荒漠和绿注的过渡地带的过渡生态类型丰富,其共同的景观结构特征是拼块破碎、呈团聚状分布,在极端干旱的北部阿拉善高平原,裸露戈壁是景观模地,占据绝对优势,蔓延度极高,其它类型是面积相对很小的异质镶嵌体。文章最后指出,在使用FRAGSTATS的栅格版本时要特别注意尺度的影响。     

塔里木河中游地区3种植物的抗旱机理研究

对塔里木河中游地区沙吉力克、阿其河等断面地下水位进行监测并对胡杨、柽柳、芦苇3种植物的可溶性糖、脯氨酸等生理指标进行测定分析.研究显示：（1）塔里木河中游地区植物生长与地下水位变化关系密切,随着不同断面地下水位埋深程度的增加,植物体内可溶性糖与脯氨酸含量呈增加趋势;（2）在干旱胁迫情况下,植物通过可溶性糖、脯氨酸等渗透调节物质的积累来提高自身的抗旱性;（3）植物叶片可溶性糖和脯氨酸的积累存在互相补偿的关系.研究表明在相同水分胁迫下,柽柳和芦苇对地下水位的变化更为敏感,胡杨的抗旱性较强.     

Effects of Anions on the Capacity and Affinity of Copper Adsorption in Two Variable Charge Soils

Effects of nitrate,(NO₃⁻) chloride (Cl⁻), sulfate (SO₄^2-, and acetate (Ac⁻) on Cu²⁺ adsorption and affinity of the adsorbed Cu²⁺ were evaluated in two Fe and Al enriched variable charge soils from Southern China. The maximum adsorption of Cu²⁺ (M, a parameter from the Langmuir isotherm model) in the presence of different anions decreased in the order Cl⁻ > Ac⁻ > NO₃⁻ > SO₄^2- for both soils. The clayey loamy soil (mixed siliceous thermic Typic Dystrochrept, TTD), developed on the Arenaceous rock, adsorbed less Cu²⁺ than the clayey soil (kaolinitic thermic Plinthudults, KTP), derived from the Quaternary red earths, regardless of anion type present in the medium. The affinity of adsorbed Cu²⁺ to both soils could be characterized by the Kd (distribution coefficient) values and successive extraction of the adsorbed Cu²⁺ with 1-mol NH₄Ac L⁻¹. The log₁₀Kd value was smaller for the TTD soil than for the KTP soil and decreased in the order of Cl⁻ > NO₃⁻ > SO₄^2- > Ac⁻ at low initial Cu²⁺ concentrations (≤40 mg Cu²⁺L⁻¹), whereas at 80 mg Cu²⁺L⁻¹, the log₁₀Kd value was similar for NO₃⁻, SO₄^2-, and Ac⁻, but was slightly higher for Cl⁻. Complete extraction of Cu²⁺ adsorbed in the presence of Ac⁻ was achieved. Influence of NO₃⁻ and SO₄^2- on the affinity of adsorbed Cu²⁺ was similar, but the effects of Cl⁻ depended on the initial Cu²⁺ concentrations. The extracted percentage of the adsorbed Cu²⁺ in the presence of NO₃⁻ or SO₄^2- increased with increasing Cu²⁺ adsorption saturation. The presence of Cl⁻, NO₃⁻, or SO₄^2- markedly decreased the equilibrium solution pH for both soils with increasing initial Cu²⁺ concentrations, and the delta pH values at the highest Cu²⁺ level were 0.5, 0.63, and 0.55 U for the TTD soil and 0.79, 0.84, and 0.93 U for the KTP soil, respectively for the three anions. The presence of Ac⁻ had a minimal influence on the equilibrium solution pH because of the buffering nature of the NaAc/HAc medium which buffered the released protons. The effects of anions on Cu²⁺ adsorption and affinity of the adsorbed Cu²⁺ were dependent on anion types and were apparently related to the altered surface properties caused by anion adsorption and/or the formation of anion– Cu²⁺ complexes.     

黑河流域中游罗布麻传粉生态学特性研究

对黑河流域中游罗布麻的开花动态、花粉活力、柱头可授性、访花昆虫种类、访花频率、花粉与胚珠比(P/O)、杂交指数(OCI)及自然条件下的座果率进行观测,结果显示:罗布麻的单花花期为4～6 d,群体花期为6～8月,花朵开裂3.5 h后,花粉活力达到最大,4 d后花粉活力下降为0,柱头可授性在开花后第2天达到最大,柱头可授性可持续4 d.访花昆虫有10余种,以膜翅目昆虫为主,姬蜂、卡切叶蜂、达戈切叶蜂、意大利蜂、黑带食蚜蝇、菜粉蝶、蚜虫为主要传粉昆虫,花粉与胚珠比(P/O)为36.2,OCI为2,实验组和对照组的座果率分别为(2.79±0.99)%和(3.41±1.05)%.实验结果表明,罗布麻为兼性自交的繁育系统,座果率偏低,虫媒在传粉过程中只是起到一定辅助作用.     

黑河下游分水后的植被变化初步研究

黑河下游地区近年来由于河水注入量的持续减少,使得依赖河水补给的地下水相应减少,造成区域性地下水位下降,从而出现了一系列的生态环境问题,大面积湿地消失,天然植被全面衰败,土地盐化加剧,胡杨和沙枣林面积减少,并以老林为主,红柳灌丛也减少,并且多已成为稀疏矮化的群落。各种禾草草甸严重退化,多以演替成苦豆子群落。为了恢复和重建受损的下游生态系统,2000年7月开始,实施了黑河下游应急生态输水工程,水流于2002年7月17日流进黑河尾闾端的东、西居延海,使干涸10年的居延海重新受到水的滋润。作者根据近三年黑河下游分水前后地下水位和植被等项内容的监测资料,探讨了地下水位与天然植被生长的相互关系。研究结果表明：分水使得该地区生态环境有了较大的改善,地下水位普遍抬升,胡杨林得到恢复,灌木荒漠植被得到部分恢复,禾草草甸植被得到一定程度的恢复。     

基于假设抽取法的黑河流域中游行业用水关联分析

基于2000—2012年张掖市混合型水资源投入产出模型,运用改进的假设抽取法,分析了张掖市6部门水资源关联效应,揭示了水资源在行业间的消耗规律,为调整产业结构提供有利的参考。研究结果表明:(1)各部门水资源直接消耗量与满足自身所需的水资源量不对等,种植业的水资源直接消耗量和纵向集成消耗量均为最大,且其纵向集成消耗水量小于直接消耗量,是张掖市经济系统中真正的水资源净输出部门。(2)种植业的内部效应和复合效应均最大,对自身的依赖性极强。服务业的净后项关联最大,对其他部门的依赖程度最高。(3)水资源在各部门之间发生了转移,种植业是张掖市经济系统中最大的水资源供给者,服务业是各部门中最大的受水者,通过中间投入的方式,由种植业到服务业的路径是最大的水转移途径,而建筑业是"纯"输入部门。(4)2000—2012年间,各部门的内部效应、复合效应、净前项关联和净后项关联均变化显著,进一步反映了产业部门水资源利用的动态关联。     

黄河中游湿地植物分类学多样性研究

在黄河中游湿地自禹门口至汾河入河口之间设置了13个样地进行植物调查,并将植物物种系统分类学中的分类学差异性指数应用到研究区域物种多样性的测度中。结果显示,样地内共记录植物75种,隶属于2门3纲18目23科61属;按所含物种数的多少统计,在门水平上主要分布在被子植物门(73种),在纲水平上主要分布在双子叶植物纲(57种),在科水平上主要集中在豆科(Leguminosae,11种)、菊科(Compositae,14种)和禾本科(Gramineae,11种),在属水平上主要集中在藜属(Chenopodium,3种)、胡枝子属(Lespedeza,3种)、蒿属(Artemisia,3种)和香蒲属(Typha,3种);一年或两年生植物最多,地上芽植物、地面芽植物和地下芽植物次之的生活型谱特征总体上反映了黄河中游湿地夏季高温多雨、冬季寒冷干旱的气候特征。用平均分类学差异指数(Δ~+)和分类学差异变异指数(Λ~+)对13个样地植物分类学多样性特征的分析表明,Δ~+和Λ~+的理论平均值分别为84.25和425.43;运用双变量分析法将Δ~+和Λ~+进行组合分析,发现汾河入河口样地(S12)的期望值较小,河津市汾河25号坝样地(S8)、闸西侧样地(S9)和万荣县西范控导工程西侧样地(S10)的期望值较大,说明样地S12的物种分类学多样性较大且物种分布较为均一,样地S8、S9、S10则与之相反。Pearson检验结果显示,平均分类学差异指数(Δ~+)、分类学差异变异指数(Λ~+)与Shannon-Wiener指数、Pielou指数、Simpson指数、Patrick指数间均无稳定的相关关系(P0.05)。     

黑河中游边缘绿洲湿润和干旱条件下棉花叶片光合特性比较

在甘肃河西走廊中部黑河中游临泽北部边缘绿洲区,测定了湿润和干旱条件下早熟陆地棉(Gossypiumhirsutum L.)品种'新陆早8号'棉花叶片的气体交换参数及叶绿素荧光参数动态日变化.结果表明:(1)不同土壤水分条件下棉花叶片均出现光合午休现象.但均未出现光抑制;干旱条件下91起棉花光合午休以非气孔因素为主,湿润条件下非气孔因素和气孔因素先后共同起作用.(2)干旱条件下棉花叶片净光合速率(Pn)在8:00～11:OO高于湿润条件下,且均值提高10.5%,而其在12:OO～18:00低于湿润条件下,且均值降低16.5%;干旱条件下叶片Pn和蒸腾速率(Tr)日均值(8:00～18:00)分别比湿润条件下降低4.9%和26.1%,水分利用效率(WUE)却提高了23.4%且达到显著水平.(3)不同土壤水分条件下棉花叶片PSlI最大光化学效率(Fv/Fm)都于14:00达全天最低值,但最低值均大于0.80.研究发现,湿润土壤条件并不能消除棉花的光合午休现象;干旱土壤条件也未使棉花出现光抑制,却使一定时段的水分利用效率显著提高.     

长江中游鱼类资源量的估算

为了解长江中游的鱼类资源现状,于2018年5和6月以及9和10月在宜昌、石首、洪湖、武汉和湖口5个江段进行了渔获物调查工作。通过统计各江段的渔业捕捞情况,计算年捕捞量。用体长股分析方法,对铜鱼(Coreius heterodon)、鳊(Parabramis pekinensis)和瓦氏黄颡鱼(Tachysurus vachelli)的资源量进行估算,并以此推算各江段的鱼类总资源量。结果显示,宜昌江段的鱼类年总资源量1077.36 t,其中,铜鱼为623.25 t;石首江段的年总资源量为2190.74 t,铜鱼为698.19 t;洪湖江段的鱼类年总资源量为58.57 t,其中,瓦氏黄颡鱼为0.41 t;武汉江段的鱼类年总资源量1010.54 t,其中,鳊为148.65 t;湖口江段的年鱼类总资源量14.55 t,瓦氏黄颡鱼为0.032 t。估算结果可以为长江中游鱼类资源保护措施的制定提供数据参考。     

黑河中游主要农作物灌溉制度优化

科学的灌溉制度是干旱半干旱地区农业生产的重要保障。黑河位于西北干旱区,是我国第二大内陆河,且当地中游农业灌溉和下游生态需水矛盾十分突出。利用DSSAT （Decision Support for Agro-technology Transfer）模型模拟了黑河中游地区玉米、小麦、油菜、马铃薯的生长情况,对比分析了四种作物生育期内需水量变化与当地降水条件、现行灌溉制度之间的差异。通过设置灌溉组合探究了四种作物最适宜的灌溉制度,并计算了优化灌溉制度下的节水潜力。结果表明：DSSAT模型通过参数校正与验证后,对四种作物生长过程模拟性能较好,产量标准化均方根误差（nRMSE）均低于15.0%,决定系数（R²）均达到0.65以上。缺水量模拟结果表明,四种作物生长季平均水分亏缺介于122.5-367.0 mm。通过调整灌溉制度,可使玉米、小麦、油菜、马铃薯的水分利用效率分别提高54.8%、25.0%、18.3%和51.3%,且产量变幅均低于5.0%,实现了高产节水的目的。在研究区实施最优灌溉制度,中游农业灌区每年可以节省8.1×10⁸ m³的水资源量,用于支持下游生态保护。     

日光温室连作土壤酚类物质变化及其对黄瓜根系抗病性相关酶的影响

研究了日光温室连作黄瓜土壤酚类物质变化及其对黄瓜根系抗病性相关酶的影响.结果表明,随着连作年限的增加,对羟基苯甲酸、阿魏酸、苯甲酸以及总量呈现明显的积累特征:种植5年、7年、9年的含量显著高于1年、3年,且9年的是1年的2倍.在低浓度处理下(0和80 μg·g^-1),前期(2、3叶期)诱导多酚氧化酶、过氧化物酶、苯丙氨酸转氨酶活性不同程度地升高,植株表现高抗性,在较高浓度下(120和160μg·g^-1),处理前期多酚氧化酶、过氧化物酶、苯丙氨酸转氨酶活性迅速降低,甚至丧失酶活性.连作土壤酚类物质浓度变化是影响日光温室黄瓜抗病性的主要因素之一.     

怒江中游西藏境内干旱河谷荒漠植被特征

基于实地调查资料,对西藏境内怒江中游河谷的特殊荒漠型植被进行了研究。结果表明：（1）22个样方中有85种维管植物,其种子植物属的分布区类型以泛热带分布为主,占21．6％;种以中国特有分布中的西南特有成分为主,占53．2％;（2）生活型谱以矮高位芽植物为主,占41．2％,地面芽植物占40．0％;（3）采用Raunkiaer频度分析,出现在10个以上样方中的物种有白刺花、垫状卷柏、芸香草和阔盖中国蕨等,频度分别是68．2％、50．0％、50．0％、45．5％;（4）根据该河谷区域的气候特点、干旱程度、群落的生态外貌特征和生活型等,并结合《中国植被》对灌丛和荒漠的划分,认为该河谷区域的植被盖度极低,不属于灌丛类型,而是非地带性的干旱河谷型荒漠植被。     

黑河中游和烟台海滨中国柽柳的传粉生态学研究

中国柽柳(Tamarix chinensis)是干旱及半干旱地区的重要建群物种.为便于其有效利用和引种栽培,对黑河中游和烟台海滨的中国柽柳的开花动态、花粉活力、柱头可授性、访花者种类、花粉-胚珠比(P/O)、杂交指数(OCI)及座果率进行观测,结果表明:黑河中游和烟台海滨柽柳的花期和柱头可授性相似,花序花期为2-5天,开花当天柱头可授活性最大,之后逐渐下降,第4天柱头无可授性;花粉活力和访花者种类差别较大,黑河柽柳开花第1天花粉活力为(62±4.31)％,最高为(82.12±7.23)％,4天后花粉完全失活.烟台柽柳的花粉活力在开花后第1天最高为(89.13±7.23)％,第4天花粉活力下降为(11±1.12)％.黑河中游和烟台海滨柽柳的访花者均以膜翅目昆虫为主,黑河柽柳以黑带斑沙蜂(Bembix melanura)、卡切叶蜂[Megechile (Amegachile) kagiana]和黑带食蚜蝇(Episyrphus balteatus)等为主要访花者;烟台柽柳以姬蜂(Ichneumon sp.)、大灰食蚜蝇(Metasyrphus corollae)和灰地种蝇(Delia platura)等为主要访花者.二者P/O值、OCI及座果率差异不显著,黑河和烟台柽柳的P/O值分别为373.6±71.9和382.1±86.2;最高座果率分别为(89.72±7.76)％和(93.17±8.21)％;OCI均为3.上述研究结果显示,黑河中游和烟台海滨柽柳均为兼性异交的繁育系统.     

沿淮中部地区草坪建设初探

通过运用样带法对沿淮中部地区草坪夏季杂草情况进行了调查 ,总结了夏季杂草分布特点 ,提供了初步防治办法 ,并对沿淮中部地区的绿化提出了初步建议     

Effect of Soil Chemical and Physical Properties on Sorption and Desorption Behavior of Lead in Different Soils of India

Lead (Pb) is a non-biodegradable contaminant, present in the environment, especially near lead-based industrial sites, agricultural lands, and roadside soils. Bioavailability of Pb in the soil is controlled by the sorption and desorption behavior of Pb, which are further controlled by the soil chemical and physical properties. In this study, sorption and desorption amounts of Pb in soil were compared with soil physical (sand, silt, clay content) and chemical (pH; electrical conductivity, EC; percent organic carbon, (%OC); cation exchange capacity, CEC) properties. Twenty-six surface soils (0–5cm), expected to vary in physical and chemical properties, were collected from different parts of India and were treated with known concentration of Pb solution (40 μg/L). The amount of Pb sorbed and desorbed were measured and correlated with soil properties using simple linear regressions. Sorption was significantly (p ≤ 0.05) and positively correlated with pH, and %OC; desorption was significantly (p ≤ 0.05) negatively correlated with the same two factors. Stepwise multiple regressions were performed for better correlations. Predicted sorption and desorption amounts, based on multiple regression equations, showed reasonably good fit (R² = 0.79 and 0.83, respectively) with observed values. This regression model can be used for estimation of sorption and desorption amounts at contaminated sites.     

Adsorption Characteristics and the Effect of Dissolved Organic Matter on Mercury(II) Adsorption of Various Soils in China

To evaluate the adsorption characteristics and effects of dissolved organic matter (DOM) from wheat straw (DOM_W) and swine manure (DOM_S) on mercury [Hg(II)] adsorption by soils, a series of experiments was conducted on 26 soils with different soil properties.Results showed that the values of K_d (a solid–liquid partition coefficient) of soils varied within a range of 0.768–14.386 L g^?1. K_d values were mainly controlled by soil organic matter (SOM), cation exchange capacity (CEC), soil nitrogen (N), and soil sulfur (S). When DOM_W and DOM_S were added to the soil samples, the amount of Hg(II) adsorbed by the soils decreased significantly. Furthermore, based on the decreased percentage of adsorption of Hg(II) by soil upon adding DOM_W (P_DOMW) or DOM_S (P_DOMS), about 73.08% soils, the values of P_DOMS were smaller than those of P_DOMW. The P_DOMW values were related to SOM, pH, free Fe oxide content, and CEC, whereas P_DOMS values were related to soil free Fe/Al oxide contents. Therefore, we should pay more attention about mercury risk caused by the addition of exogenous organic matter in soils, especially for the soils with low or high pH, less SOM, low CEC, and less free Fe/Al oxide.