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1.
An analysis of Cr (Ⅵ)-sorbed surface of the soils by using a scanning electron microscope and an electron probe microscope has proved that aluminium is the chief element affecting Cr (Ⅵ) adsoption. As the ionic strength of the solution increased, the amounts of Cr (Ⅵ) adsorbed by goethite and soils decreased. Cr (Ⅵ) adsorption was greatly depressed in the presence of SO42-, WO42-, MoO42-, HPO42- and H2PO4- which competed for anion adsorption sites. The depressing extent of these anions was found to follow the sequence: HPO42-, H2PO4->MoO42->WO42->SO42->>Cl-, NO3-. The amounts of Cr (Ⅵ) desorption varied with different extractants. 相似文献
2.
本文研究了土壤中可变电荷表面磷的解吸特性。结果表明,磷解吸量与吸附量成正相关,并与直线方程和指数方程拟合。其平均解吸百分数依次为:高岭石(66%)>无定形硅酸铝(60%)>砖红壤粘粒(55%)>>无定形氧化铁(29%)>三水铝石(23%)>>火山灰粘粒(9%)。解吸体系的pH是借对磷酸根质子的解离和表面电荷的影响而制约解吸量。F-和OH-离子对磷酸盐化的三水铝石连续解吸的结果表明,磷酸根和氟离子在三水铝石表面的吸附量或剩余量之和均较为接近,这揭示了H2PO4-和F-离子之间既竞争又相互补充表面空位。它可作为一种区分磷吸附形态和沉淀的定量方法来进一步研究。 相似文献
3.
利用长期定位试验 ,比较了长期施用含SO42-和Cl- 化肥 22年后稻田土壤的 pH值、养分状况及其吸附解吸特性。结果表明 ,长期施用含SO42-化肥 ,土壤有机质、速效氮和速效钾的含量较高 ,但全量氮磷钾的含量较低 ;长期施用含Cl- 化肥 ,土壤全量氮磷钾和速效磷的含量较高 ,但pH值相对较低。长期施用含上述二种阴离子的化肥后 ,土壤对H2PO4-的最大吸附量均较大 ,且在Cl- 处理下土壤对H2PO4-吸附的结合能较大 ,而SO42-处理下土壤在同等吸附量时对H2PO4-的解吸量相应较多。长期施用含SO42-的化肥亦使土壤对钾素的供应强度较大 (ΔK0的绝对值较大 )、缓冲能力增强 (AR0值较高 ) ,而长期施用含Cl- 的化肥时则与SO42-相反 相似文献
4.
用电导频散法研究Cl-、SO42-和H2PO4-阴离子与土壤的相互作用 总被引：2，自引：0，他引：2
本文介绍了采用电导频散装置测量分别含有10-4mol/LHCl、5×10-5mol/L H2SO4和10-4mol/L H3PO4的黄棕壤、棕壤、黑土和砖红壤悬液(20-30g/kg)的电导频散曲线,频散曲线上均呈现频率范围相当宽的坪区,频散曲线的特性分析结果表明,黄棕壤和棕壤在3种酸溶液中的始散频率(0.6-1kHz)低于黑土悬液(16-28kHz),而砖红壤的始散频率最高(25-47kHz;Cl-、SO42-和H2PO4-离子与4种土壤的相对亲合力(REC1.5/RECtp-1)顺序为Cl- < SO42- < H2PO4-,在不同土壤之间的顺序则随酸溶液而异. 相似文献
5.
3 种挺水植物吸收水体NH4+、NO3-、H2PO4- 的动力学特征比较 总被引：3，自引：1，他引：2
本文用动力学试验研究了具有景观价值的3 种挺水植物—— 水生美人蕉(Canna generalis)、细叶莎草(Cyperus papyrus)、紫芋(Colocasia tonoimo)对H2PO4-、NH4+、NO3- 的吸收特征及差异。试验结果表明: 3 种挺水植物吸收H2PO4- 时, 美人蕉的吸收速率最快, 且在较低离子浓度条件下也可以吸收该离子, 说明其具有嗜磷特性, 能够适应广范围浓度H2PO4- 环境; 吸收NO3- 时, 细叶莎草的速率最快, 但对低浓度NO3- 环境的适应能力较差, 美人蕉吸收NO3- 的特性与细叶莎草刚好相反; 吸收NH4+ 时, 细叶莎草的吸收速率最快, 且在低浓度NH4+ 环境下仍能吸收该离子, 而美人蕉的吸收速率最慢, 但能在低浓度NH4+ 环境下吸收该离子。说明不同植物对养分的吸收特性存在较大差异, 各自的污染水体修复适用范围也不同。美人蕉可用于各种浓度H2PO4- 污染的水体修复; 而NO3- 污染严重的水体最适宜用细叶莎草作先锋植物, 修复到一定程度后再种植美人蕉来维持水质; 细叶莎草在各种浓度NH4+ 污染的水体中均适用, NH4+ 污染较轻的水体也可用美人蕉修复。 相似文献
6.
第四纪红色粘土发育的红壤中营养元素的淋失 总被引：13，自引：2，他引：11
A red soil derived from Quaternary red clay was employed to study nutrient leaching with soil columns repacked in laboratory. The objective was to identify the effects of fertilization practices on leaching patterns and magnitudes of Ca2+, Mg2+, K+, NH4+, and NO3-. The treatments were CK (as a control), CaCO3, CaSO4, MgCO3, Ca(H2PO4)2, urea, KCl, and multiple (a mixture of the above-mentioned fertilizers). The fertilizers were added to the bare surface of the soil columns, and then the columns were leached with 120 mL deionized water daily through peristaltic pumps over a period of 92 days. Leaching processes of NH4+, and NO3- were only measured in CK, urea, and multiple treatments which were directly related to N leaching. Results showed that sole application of CaSO4, and Ca(H2PO4)2 scarcely had any effect on the leaching losses of Ca2+, Mg2+, and K+; the application of MgCO3 stimulated the leaching of Mg2+; the application of CaCO3 promoted the leaching of Ca2+, Mg2+ and K+; urea treatment also promoted the leaching of K+ and NH4+, and NO3- leaching mainly occurred at late stage of leaching process in particular; under KCl treatment, leaching of Ca2+, Mg2+, and K+ was promoted to a large extent; under multiple treatment, leaching of Ca2+, Mg2+, K+, NH4+, and NO3- was all increased and NO3- was mainly leached at the end of leaching process and still had a trend of increase. 相似文献
7.
本文选择了浙江、江苏15个性质变化范围较大的土壤样品,研究在两种支持电解质、不同pH条件下对磷酸根的吸持反应。结果表明,加碱提高强酸性土壤的pH值,导致交换性铝的水解和羟基铝聚合物的生成,增加对磷的吸持。磷酸根同酸性土壤的反应,可促进交换性铝的水解,释放出H+,降低体系的pH。在CaCl2介质中,当pH>6时,可能有磷酸钙类盐形成,使溶液中磷浓度显著降低。有机质对土壤吸持磷有重要影响。在低pH下有机质通过与Al3+形成络合物,阻碍溶液中A13+的水解,并与磷酸根竞争羟基铝化合物表面的反应点位,从而降低酸性土壤对磷酸根的吸附量。 相似文献
8.
Plants show different growth responses to N sources supplied with either NH4+ or NO3-. The uptake of different N sources also affects the rhizosphere pH and therefore the bioavailability of soil phosphorus, particularly in alkaline soils. The plant growth, P uptake, and P availability in the rhizosphere of oat (Avena nuda L.) grown in hydroponics and in soil culture were investigated under supply with sole NH4+-N, sole NO3--N, or a combination. Sole NO3--fed oat plants accumulated more biomass than sole NH4+-fed ones. The highest biomass accumulation was observed when N was suppliedw ith both NH4+-N and NO3--N. Growth of the plant root increased with the proportion of NO3- in the cultural medium. Better root growth and higher root/shoot ratio were consistently observed in NO3--fed plants. However, root vigor was the highest when N was supplied with NO3-+NH4+. NH4+ supply reduced the rhizosphere pH but did not affect P uptake by plants grown in soils with CaHPO4 added as P source. No P deficiency was observed, and plant P concentrations were generally above 2 g kg-1. P uptake was increased when N was supplied partly or solely as NO3--N, similarly as biomass accumulation. The results suggested that oat was an NO3--preferring plant, and NO3--N was essential for plant growth and the maintenance of root absorption capacity. N supply with NH4+-N did not improve P nutrition, which was most likely due to the absence of P deficiency. 相似文献
9.
柑桔根系对缺铁的生理反应 总被引：1，自引：0，他引：1
柑桔在缺铁条件下,幼苗根系分泌H+和还原Fe3+的能力增加,与植株吸收铁素营养的能力相一致。摘除缺铁失绿的新叶和顶芽,抑制根系分泌H+和Fe3+还原物;但随着新叶的重新长出,根系分泌H+和Fe3+还原物的速率逐渐提高。说明缺铁失绿的组织能调控根系分泌H+和Fe3+还原物。在营养液中加入0.1nmol/L生长素(IAA),能解除因缺少失绿组织对根系分泌H～+产生的抑制作用。此外,在缺铁条件下,吸铁能力较强的酸橙根尖发生膨胀,有利于铁的接触吸收。 相似文献
10.
伴随阴离子对马铃薯种植冲击土中钾素固持与淋溶的影响 总被引：1，自引：0，他引：1
A column study was carried out to assess the influence of accompanying anions on potassium (K) leaching at potato growing sites with different soil textures (sandy loam and clay loam) in northwestern India. Potassium was applied in the top 15 cm layer of soil column at 30 and 60 mg K kg-1 through different sources having different accompanying anions (Cl-, SO42-, NO3- and H2PO4-). Maximum K was retained in the top 0--15 cm layer with a sharp decrease in K content occurring in 15--30 cm layer of the soil column. The trend was similar for both levels of applied K as well as frequency of leaching and soil type. The decrease of K content in soil column after four leaching events was maximum in case of Khanaura sandy loam, while only minor decrease was observed in Hundowal clay loam when K was applied at 60 mg K kg-1, indicating higher potential of clay rich soil to adsorb K. In general, the K leaching in presence of the accompanying anions followed the order of SO42- ≤ H2PO42- < NO3- = Cl-. Highest 1 mol L-1 CH3COONH4-extractable K was retained when K was applied along with SO42- and H2PO4- anions, and the least was retained when accompanying anion was Cl-1. The influence of anions was more pronounced in the light textured soil and at high amounts of K application. Higher levels of K application resulted in higher losses of K, especially in sandy loam soil as observed from the leachate concentration. Among the different K sources, the maximum amount of K leaching was noticed in the soil column amended with KCl. After four leachings, the maximum amount of K leached out was 6.40 mg L-1 in Hundowal clay loam and 9.29 mg L-1 in Khanaura sandy loam at 60 mg K kg-1 of soil application through KCl. These concentrations were lower than the recommended guideline of the World Health Organisation (12.00 mg L-1). 相似文献
11.
冬季咸水结冰灌溉是将冬季自然冷资源与滨海盐碱地区丰富的咸水资源相结合, 通过自然结冰使咸淡分离, 再利用结冰融化时咸水先流出淡水后流出会对土壤起到一定的洗盐作用的原理, 对盐碱地进行改良。本文通过大田试验, 研究了冬季咸水结冰灌溉及改良剂对天津滨海盐碱地水盐运移的影响。结果表明, 通过咸水结冰灌溉能降低根层土壤含盐量, 且灌溉水量与土壤含水量呈正相关。冬季咸水结冰灌溉初期可能会引起土壤碱化, 但随着冰层融化及时间的推移, 各处理的碱化趋势会逐渐消弱。在滨海盐土施用磷石膏能够降低HCO3-含量, 增加SO42-、Ca2+含量, 有效降低Cl-、Na+在总盐分中的比例, 且磷石膏施用量越大, 根层土壤的pH 越低、保水能力越强(7 500 kg·hm-2 磷石膏>4 500 kg·hm-2 磷石膏); 施用磷石膏和大水量的咸水结冰灌溉都能很好地促进柽柳生长,且咸水冬季结冰灌溉和施用磷石膏配合(1 350 m3·hm-2 结冰灌溉+7 500 kg·hm-2 磷石膏)效果最好。因此, 咸水结冰灌溉配合改良剂应用可有效改良滨海盐土, 改善因咸水结冰灌溉而带来的土壤碱化问题, 为早期植物萌发生长提供有利条件。 相似文献
12.
“零排放”复合生物净化模式用于循环水养鲍系统的试验研究 总被引：3，自引：1，他引：3
采用水生植物滤池(UB和PUB)和固定膜生物滤池（SB）的复合净化模式，对鲍鱼养殖水体和系统排放水体进行净化，实现了循环水养鲍系统的清洁生产。试验结果表明，植物滤池UB对养殖水体中总氨氮(TAN)具有很高的吸收效率，从而降低了SB的硝化负荷，大大减少了TAN、NO－2-N、NO－3-N和COD的积累，在整个试验过程中，养殖水体中TAN、NO－2-N、NO－3-N和COD的浓度分别低于0.19、0.01、1.75和1.20 mg/L。由于UB滤池的吸收作用和SB的硝化作用，养殖水体中PO3-4的浓度一直保持在0.30 mg/L以下。另外，这种复合净化模式具有调节水体pH值的作用，在试验期间，养殖水体中的pH值一直保持在8.11～8.14的良好水质范围，对鲍鱼的养殖十分有利。系统排放水经另一植物滤池PUB吸收净化后，PO3-4浓度降至0.22 mg/L 以下，NO-3-N的浓度甚至降至0.10 mg/L以下。本文还建立了养殖循环水体中无机氮的循环模型，用于对养殖水体中TAN、NO－2-N和NO－3-N的预测和控制。 相似文献
13.
14.
用营养液培养方法研究了铁和两种形态氮素(NO3--N和NH4+-N)对玉米植株吸收氮、磷、钾等大量元素和钙、镁等中量元素及其在体内分布的影响。结果表明:与NO3--N相比,供应NH4+-N促进了玉米对氮的吸收,在缺铁条件下,降低了对磷、钾、钙及镁的吸收。铁和NH4+-N都显著提高了玉米植株各器官中氮的含量。与NH4+-N处理相比,NO3--N处理的新叶中磷含量显著增加,但铁的供应对植物体内磷的含量无显著影响。使用NO3--N显著提高了玉米新叶和老叶中钾的含量,根和茎中钾的含量无明显影响。铁的供应降低了新叶和老叶中钾的含量。供铁时,NH4+-N处理的玉米新叶中钙和镁的含量显著低于NO3--N处理,而在缺铁时则无显著差异。 相似文献
15.
磷胁迫条件下油菜、肥田萝卜对难溶性磷的活化与利用 总被引：1，自引：2，他引：1
通过砂培试验研究了北方食用油菜和南方绿肥作物肥田萝卜两种植物在缺磷胁迫条件下对难溶性磷酸盐Ca3(PO4)2和AlPO4的活化利用情况。试验结果表明,在仅供应一种难浴性磷酸盐时,油菜和肥田萝卜对磷酸铝和磷酸三钙都有较大程度的活化与利用。在施用AlPO4时肥田萝卜地上部吸磷量达到供应等磷量水溶性磷酸盐时的90％;在施用Ca2(PO4)2时油菜地上部吸磷量达到供应等磷量水溶性磷酸盐时的49％。植物干物重的测定结果说明,在缺磷时,难溶性的Ca3(PO4)2及AlPO4对油菜和肥田萝卜均有促进生长的作用。但是,油菜与肥田萝卜对Ca3(PO4)2和AlPO4的活化利用程度却存在着一定差异。表现为油菜对Ca3(PO4)2的利用能力强,而肥田萝卜对AlPO4的利用能力强。 相似文献
16.
影响土壤镉吸持和解吸的因子 总被引：10，自引：0，他引：10
研究了土壤的pH、离子浓度(0.01mol/L、0.05mol/L、0.1mol/L)、阴(阳)离子种类(NO3-、Cl-、OAc-、SO42-、HPO4-及Zn和Pb)及石灰和葡萄糖对土壤镉吸持及其解吸的影响。 相似文献
17.
尿素肥斑中氮素形态转化初探 总被引：1，自引：0，他引：1
采用特制模拟容器,通过尿素扩散形成营养斑,观察斑内NH4+、NO2-和NO3-浓度变化及它们之间的相互转化。结果表明,NH4+、NO2-和NO3-浓度在距离肥斑7～8cm处的微域达到最大,尤以NO2-浓度增加较为显著,是一般土壤NO2-水平的数千倍。随培养时间增加,NO2-和NO3-最大浓度峰向施肥点移动,但两者浓度变化趋势不同,NO2-浓度在21d前随培养时间增加而增加,之后随培养时间增加而下降,而NO3-浓度随培养时间增加一直增加。结果还表明,NO2-是尿素营养斑内主要离子形态,从NH4+到NO2-的转化比较迅速,而NO2-转化为NO3-不是短暂的过程,这可能与施肥引起的土壤pH值变化有很大关系。 相似文献
18.
Fifteen upland soils collected from the major arable areas in North China were used to assess the availability of soil sulfur (S) to plants in a pot experiment. Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. In addition, mineralizable organic S, organic S, N/S ratio, sulfur availability index (SAI) and available sulfur correction value (ASC) in soils were also determined. The S amount extracted by 1.5 g L-1 CaCl2 was nearly equivalent to that by 0.25 mol L-1 KCl (40 ℃), and both of them were slightly smaller than that by 0.01 mol L-1 Ca(H2PO4)2 solution, as measured by turbidimetric method or ICP-AES. The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES. All methods tested except that for organic S and N/S ratio produced satisfactory results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment. In general, 0.01 mol L-1 Ca(H2PO4)2-extracted S determined by ICP-AES or turbidimetric method and 0.25 mol L-1 KCl (40 ℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S. 相似文献
19.
不同铵硝配比对弱光下白菜氮素吸收及相关酶的影响 总被引：2，自引：0，他引：2
以黑色遮阳网覆盖模仿弱光环境, 使光照强度为自然光的20%左右, 以自然光照为对照, 采用精确控制水培溶液氮素营养, 研究NH4+-N/NO3--N 比例分别为0/100、25/75、50/50、75/25、100/0 对弱光下白菜氮代谢及硝酸还原酶和谷氨酰胺合成酶活性的影响。结果表明, 弱光下, 白菜的鲜重及叶片总氮量以NH4+-N/NO3--N 比为25/75 时最大, NH4+-N/NO3--N 比为100/0 时最低。随弱光处理的进行, 白菜叶片中硝酸还原酶活性及谷氨酰胺合成酶活性均呈下降趋势, 但NH4+-N/NO3--N 比为25/75 时, 可维持叶片内较高的硝酸还原酶活性及谷氨酰胺合成酶活性。试验表明, NH4+-N/NO3--N 比25/75 是白菜在弱光下生长的较适宜氮素形态配比。 相似文献
20.
本试验研究了一种合成水钠锰矿对Mn2+的持留机理和Mn2+被吸附后的去向,并进一步探讨了三种锰盐溶液(MnSO4,MN(NO3)2和MnCl2)对水钠锰矿晶体结构变化的影响。.试验结果表明,水钠锰矿对MN2+离子的吸附包括专性吸附和非专性吸附。随着吸附后的老化过程,吸附在矿物表面的锰逐渐扩散到晶格内,其置换性随之降低。.在MnSO4,Mn(NO3)2和MnCl2溶液中,水钠锰矿最终转化成六方锰矿(Nsutite),一种比水钠锰矿更稳定,结晶更好的晶体。MnSO4溶液在加入水钠锰矿后pH值比其它两种溶液高,除生成六方锰矿外还形成大量拉锰矿(Ramsdellite)。随着生成新矿物的老化,最初被吸附的Mn被固定在晶格内而失去其置换性和生物有效性。 相似文献