黄瓜适宜的负压灌溉条件与养分配比研究

采用负压灌溉装置研究不同负压下砂壤质潮土水分运移以确定黄瓜适宜负压值,并进一步研究不同养分配比对黄瓜产量和品质的影响,为黄瓜确定最佳养分配比。本研究应用平面式土箱,在室内研究0、-5、-10和-15 k Pa水分运移情况,通过测定土壤含水量确定适宜的负压值。盆栽试验研究了不同养分配比对黄瓜产量、品质等影响,共设置不同养分配比(N∶P_2O_5∶K_2O)6个处理:T1(常规灌溉,1∶0.7∶1)、T2(负压灌溉,1∶0.7∶1)、T3(1∶0.7∶1.2)、T4[0.9∶0.7∶1+双氰胺(DCD)+氢醌(HQ)]、T5(0.8∶0.7∶1+DCD+HQ、T6(0.7∶0.7∶1+DCD+HQ),T2~T6设定负压值为-5~-10 k Pa。在黄瓜收获期采集黄瓜植株样品,测定黄瓜品质指标和养分吸收量。结果表明,在-5~-10 k Pa条件下,土壤含水量为15.83%~21.63%,可以较好地满足黄瓜生长发育的要求。在灌水量、养分配比和施肥量一致的条件下,T2比T1提高黄瓜产量3.24倍,达到了显著水平。负压(-5 k Pa)条件下不同养分配比中,T3(1∶0.7∶1.2)比传统配比T2(1∶0.7∶1)可以显著提高黄瓜产量,达到51.1%。T3能够提高黄瓜Vc和可溶性糖含量,并降低硝酸盐含量19.8%。减氮10%、20%和30%与DCD和HQ配合下,维持了与传统配比T2相当的黄瓜产量。与T2(1∶0.7∶1)配比相比,T4(0.9∶0.7∶1)可以显著提高黄瓜可溶性糖含量36.7%,降低硝酸盐含量34%,其他处理之间可溶性糖和硝酸盐无明显规律。总之,负压灌溉水肥一体化条件下,适当提高钾的配比T3(1∶0.7∶1.2)可以提高黄瓜的产量并改善其品质;减氮添加DCD和HQ的T4(0.9∶0.7∶1)维持了全氮量处理的黄瓜产量,并改善品质,这为化肥减施,减轻由此带来的环境污染提供了科学依据。     

几种新型复合肥对基质栽培生菜品质的影响

以珍珠岩、煤渣、河沙混合物为培养基质,采用盆栽方法研究了3种新型复合肥即生物复合肥、有机无机复合肥、全有机复合肥对生菜产量、硝酸盐含量、重金属含量和营养品质的影响。结果表明,生菜产量以有机无机复合肥>生物复合肥>对照(无机营养液)>全有机复合肥,处理间差异极显著。不同处理生菜硝酸盐含量为1375～3935mg/kg,以无机营养液最高,有机无机复合肥最低,3种新型复合肥较对照生菜硝酸盐含量降低37.9%～72.5%。生菜中Hg、Pb、Cr含量,除全有机复合肥处理Hg含量(0.0101mg/kg)和对照处理Pb含量(0.235mg/kg)略超标外,其余各处理3种重金属含量低于限量值且较对照降低20.8%～83.1%。复合肥各处理生菜中的Hg、Pb、Cr累积量分别占肥料总量的11.1%～63.0%、38.2%～78.7%和10.9%～53.5%。施用复合肥明显提高生菜可溶性糖和Vc含量,但对氨基酸含量的影响不一致。     

施氮对小白菜产量和品质的效应

田间试验研究了施氮对两种肥力土壤小白菜产量、硝酸盐含量和营养品质的影响。结果表明,施氮量与小白菜产量呈显著(低肥力)和极显著(中肥力)的二次回归关系,中、低肥力土壤施氮小白菜分别增产141.2%~309.4%和149.5%~617.6%;低肥力土壤小白菜产量仅为中肥力土壤的28.6%~49.5%。施氮75~300kg.hm-2提高小白菜硝酸盐含量9.9%~33.3%(中肥力,75 kg.hm-2处理除外)和240.3%~363.6%(低肥力),硝酸盐含量以中肥力土壤>低肥力土壤(N 150 kg.hm-2处理除外)。施氮降低中肥力土壤小白菜Vc含量、提高氨基酸含量,对可溶性糖影响不大;低肥力土壤施氮降低小白菜Vc、氨基酸、可溶性糖含量。     

城市雨水对生菜产量品质与重金属含量的影响

作为都市农业灌溉用水,城市雨水对农产品食品安全和营养品质的影响深受关注。论文收集自然雨水(T1)、屋顶雨水(T2)和路面雨水(T3),静置沉淀后配置营养液进行水培生菜种植,测量生物产量、生理指标(叶绿素含量、净光合速率、根系活力)、营养指标(可溶性糖、可溶性蛋白、维生素C、硝酸盐)和元素含量(Ca、Fe、Mg、Zn、As、Cd、Pb),结果表明:城市雨水重金属含量低于国家标准,可以作为农业灌溉用水;雨水栽培生菜比自来水栽培生菜长势弱、产量低,路面雨水栽培生菜产量最低,单株干质量仅为3.57 g;雨水降低了生菜叶绿素含量和净光合速率,提高了生菜根系活力,屋顶雨水生菜和路面雨水生菜根系活力分别为3.17和4.08 mg/(g·h),雨水栽培生菜的根冠比大于自来水生菜;雨水栽培生菜蛋白质、糖类和Vc含量不比自来水栽培生菜低,自然雨水生菜蛋白质质量分数4.97 mg/g,路面雨水生菜可溶性糖含量1.00%,路面雨水生菜Vc含量1.52 mg/g,分别为各项指标的最高值;供试生菜硝酸盐含量分别为5.62、5.48、6.04和7.04 mg/g,都超过了国家标准3.00 mg/g,这与试验采用1倍剂量营养液和采用硝酸调节p H值有关;雨水生菜有益元素Ca、Mg含量高于自来水生菜,Fe含量低于自来水生菜,雨水生菜总体品质略好于自来水生菜;自来水、自然雨水、屋顶雨水和路面雨水栽培生菜含As量分别为5.83、4.10、4.53和4.60μg/kg,含Cd量分别为0.76、0.78、2.59和1.37μg/kg,含Pb量分别为102.37、118.63、151.53和123.37μg/kg,远小于国家限量值,满足食品安全要求。总之,利用城市雨水作为都市农业灌溉用水,作物长势弱,产量低,但营养品质略好,食品安全,将城市雨水作为都市农业灌溉用水是可行的。     

施肥对酸性菜园土壤莴笋硝酸盐和叶片养分形态的效应

通过田间试验研究了3种酸性菜园土壤(强酸性、酸性和微酸性土壤)不同氮磷钾配比及其与硝酸盐复合控制剂配施对莴笋产量、硝酸盐及叶片养分形态的影响。结果表明,莴笋产量以微酸性土>酸性土>强酸性土,酸性和强酸性土壤上配施硝酸盐复合控制剂可使莴笋显著增产(达6.2％～18.2％),而微酸性土壤则相反。HNK配施硝酸盐复合控制剂在3种土壤上分别降低莴笋茎和叶硝酸盐含量25.1％～76.3％和3.1％～27.7％(微酸性土除外),降低作用以茎>叶,以HNK+C2处理效果最好。莴笋叶片硝酸盐含量以酸性土壤>微酸性土壤>强酸性土壤,茎中硝酸盐以酸性土壤为最高。莴笋叶片氮、磷、钾形态分别以蛋白氮、非蛋白磷、非蛋白钾为主,HNK配施硝酸盐复合控制剂(HNK+C3除外)提高莴笋叶片蛋白氮占全氮、蛋白磷占全磷和蛋白钾占全钾的比例。莴笋叶片硝酸盐含量与全氮、蛋白氮、全磷、蛋白磷和蛋白钾含量呈极显著负相关。     

糖醇和氨基酸对小白菜钙营养及生长、 品质的影响

【目的】小分子有机物在农业上的应用研究大多针对其促进作物生长、 改善品质等的营养效果,较少研究其对养分有效性及吸收利用的影响,对中微量元素吸收利用影响的研究更少。本研究选用糖醇和氨基酸为研究对象,研究了小分子有机物质对小白菜生长、 品质和养分吸收以及对钙有效性的影响。【方法】以小白菜为供试作物进行盆栽试验。试验以喷清水为对照,设置氨基酸(甘氨酸、 谷氨酸), 糖醇(甘露醇和木糖醇)和硝酸钙单独喷施,氨基酸(甘氨酸、 谷氨酸)和糖醇(甘露醇和木糖醇)分别与硝酸钙配合喷施,共计10个处理,每个处理6次重复,随机区组排列。试验中氨基酸喷施浓度为250 mg/L,糖醇喷施浓度为150 mg/L,硝酸钙喷施浓度为Ca2+ 130 mg/L。收获后测定植株生物量和维生素C、 可溶性糖、 硝酸盐和可溶性蛋白的含量,分析植株矿质元素氮、 磷、 钾和钙的吸收量。【结果】 1)叶面喷施糖醇和氨基酸明显促进了小白菜生长和养分吸收,并改善了其品质。与喷施清水(CK)相比,喷施糖醇和氨基酸可使小白菜生物量平均增加9.17%,维生素C、 可溶性糖和可溶性蛋白含量分别平均增加20.96%、 50.78%和30.66%,硝酸盐含量平均降低31.07%,氮、 磷、 钾吸收量分别平均增加12.43%、 15.24%和42.16%,钙吸收量增加显著,平均增加25.65%; 2)糖醇和氨基酸分别与硝酸钙混合施用可有效促进钙的吸收,提高硝酸钙在小白菜上的应用效果。与单独喷施硝酸钙相比,糖醇和氨基酸与硝酸钙混合喷施可使小白菜生物量平均增加17.44%,小白菜维生素C、 可溶性糖和可溶性蛋白含量分别平均增加14.23%、 45.27%、 33.43%,对氮、 磷、 钾养分吸收量分别平均提高38.25%、 16.13%、 25.11%,对钙养分的吸收量平均增加27.75%;与单独喷施小分子有机物(氨基酸和糖醇)相比,糖醇和氨基酸与硝酸钙混合喷施使小白菜生物量平均增加12.04%,对钙养分的吸收量平均增加17.60%。【结论】叶面喷施糖醇和氨基酸能有效增加小白菜生物量、 改善其品质并促进其对养分的吸收,糖醇和氨基酸分别与硝酸钙混合施用可有效促进钙的吸收,提高硝酸钙在小白菜上的应用效果。因此,小分子有机物糖醇和氨基酸可用作钙肥的有效助剂,用以促进作物对钙的吸收利用,提高钙养分的有效性和钙肥的应用效果。     

黄土高原南瓜高糖低硝酸盐施肥模式研究

采用N、P、K3因素最优设计,在陕北黄土高原进行了南瓜氮、磷、钾用量及其肥效反应模式田间试验,研究不同施肥量对南瓜硝态氮、可溶性糖两项营养品质的影响,旨在探讨南瓜品质高糖低硝酸盐的N、P、K肥效反应模式,提出优化的施肥方案。结果表明,N肥单因素对南瓜硝态氮和可溶性糖含量影响最大,K肥单因素对南瓜硝态氮和可溶性糖含量影响不显著,N与P交互作用对南瓜高糖低硝酸盐影响显著,K肥施用量一定时,氮肥与磷肥的施用量不易过大。根据南瓜N、P、K肥效反应模式,筛选出南瓜品质硝态氮含量在200mg·kg-1以下、可溶性糖含量在7%以上的较佳施肥量为施氮95～120 kg·hm-2,施磷40～70 kg·hm-2,施钾35～80 kg·hm-2,N∶P2O5∶K2O=1∶0.42∶0.37。     

液培条件下养分组成对叶菜硝酸盐及营养品质的影响

采用液培试验研究了养分组成对生菜和莴笋2种叶菜生长、硝酸盐含量及营养品质的影响，结果表明：（1）在氮肥用量相等时，增施肥和钼肥，降低营养液NO3^-N与NH4^-N比例及增施氮、钾肥、均降低了2种叶菜的硝酸盐含量；（2）生菜以增施磷肥和钼肥，NO3^--N:NH4^ -N=8:2处理时，使生菜硝酸盐含量减少19．7％，同时获得较高产量及营养品质；莴笋在营养液配方以增施磷肥和钼肥，NO3^--N:NH4^ -N=6:4(柠檬酸叶面喷施)处理最佳、使茎、叶硝酸盐含量分别降低39．5％、17．0％，改善了营养品质，提高了产量；（3）改变氮肥形态比,产施磷、钼肥，同时增加氮、钾用量，莴笋产量增加36．8％，茎、叶硝酸盐含量降低8.5%,9.8%,营养品质改善，而生菜产量降低16．3％，且对营养品质不利。     

营养液浓度对水培生菜生长和硝酸盐积累的影响

该文研究了4种营养液浓度处理(山崎生菜配方的1/4(1/4s)、1/2(1/2s)、1(1s)和2(2s)单位)对水培生菜(品种为“弘农”和“绿领”)生长、硝酸盐积累和品质的影响。结果表明,1/2单位营养液浓度处理下生菜地上部和根的鲜重、叶长和叶宽最大,而2个单位营养液浓度处理下上述指标最小。不同营养液浓度处理下叶片硝酸盐积累的高低顺序为2s>1s>1/2s>1/4s,2个单位营养液浓度处理下生菜生长发育后期叶片中的SOD活性和M DA含量最高。对采收时生菜品质的分析表明,生菜体内的硝酸盐含量随着营养液浓度的增加而迅速上升,2个单位营养液浓度处理下生菜叶片中硝酸盐、可溶性糖和可溶性蛋白质R含量最高。综合考虑产量和品质,采用1/2单位的山崎生菜配方是适合生菜水培的营养液配方。     

弱光条件下光质和光周期对水培生菜生长与品质的影响

在弱光条件的人工光植物生长室中,设置两种不同红蓝光比例光质和两种不同光周期,水培盆栽红叶生菜（R）、绿叶生菜（G）和紫叶生菜（P）,采收后测定3种生菜的生物量指标以及抗氧化物、可溶性糖等营养品质指标,以研究弱光条件下光质和光周期对3种叶色水培生菜产量和品质的影响。结果表明：（1）生菜产量主要受光周期影响,营养品质指标受光质和光周期的综合影响。光照时间延长显著增加了3种生菜叶面积。绿叶生菜和红叶生菜单位叶面积鲜重在不同光质及光周期下无显著差异。紫叶生菜单位叶面积鲜重对光周期变化的反应则因光质环境而异。延长光周期使3种叶色生菜地上部鲜重提高一倍多,但3种生菜地上部鲜重受光质影响不显著。（2）延长光照时长对3种生菜营养品质的影响因光质而异。在红蓝1:2光质下,延长光照时长降低了绿叶生菜总酚和类黄酮相对含量以及抗坏血酸和可溶性蛋白含量,提高了红叶生菜花青素和可溶性糖含量,但降低了抗坏血酸和可溶性蛋白含量,紫叶生菜总酚相对含量得到提高,但抗坏血酸含量显著降低。在红蓝2:1光质下,延长光照时长显著提高了绿叶生菜总酚和类黄酮相对含量,抗坏血酸含量有所降低,红叶生菜总酚和类黄酮相对含量、抗坏血酸、可溶性糖和可溶性蛋白含量均显著降低,紫叶生菜总酚含量显著提高。说明在弱光条件下延长光照时长可以显著提高3种不同叶色生菜产量。在红蓝1:2光质下,延长光照时长使红叶生菜的花青素含量和可溶性糖含量得到显著提高。在红蓝2:1光质下,延长光照时长可以提高绿叶生菜和紫叶生菜营养品质。     

Phytotoxicity of cobalt,vanadium, titanium,silver, and chromium

Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10^‐5 M) and 142 (with 10^‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10^‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10^‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10^‐4 M AgNO₃; at 10^‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10^‐5 N Cr₂O₇ were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr₂(SO₄)₃ was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.     

Bioavailability of As,Cd, Co,Cr, Cu,Hg, Mo,Ni, Pb,Se, and Zn from Biosolids Amended Compost

Appropriate compost standards are being considered in Canada. Five aspects of compost safety and quality are being evaluated; probably the most controversial aspect is the standards for metals in compost. In order to assist in the development of appropriate standards, the authors began an extensive research project in October, 1993 to determine the bioavailability of metals from compost and compost-metal mixtures. Swiss chard was grown in compost-amended soils or compost in a growth room using five treatments of increasing percentages of compost in the media (0, 25 percent, 50 percent, 75 percent, 100 percent compost (v/v)). A Truro loamy sand and a race-track manure-biosolids compost (RTM-biosolids) supplemented with a high metal biosolids were used in a completely randomized design with five replicates. Dry matter yield, metal content in plant tissue, and total metal uptake were evaluated as well as the total and DTPA-extractable metal content in the compost-soil mixes. The results of this and five other experiments conducted by the authors will help determine whether the suggested limits for As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se and Zn in composts are appropriate.     

Variation of N,P, K,Ca, Mg,Mn, Zn,and al in slash pine foliage

Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors^1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana ¹, P. taeda ³, P. strobus ⁴, P. resinosa ⁴, P. sylvestris ⁵, and P. radiata ^6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.     

Cooking,Roasting, and Fermentation of Chickpeas,Lentils, Peas,and Soybeans for Fortification of Leavened Bread

The effects of cooking, roasting, and fermentation on the composition and protein properties of grain legumes and the characteristics of dough and bread incorporated with legume flours were determined to identify an appropriate pretreatment. Oligosaccharide content of legumes was reduced by 76.2–96.9% by fermentation, 44.0–64.0% by roasting, and 28.4–70.1% by cooking. Cooking and roasting decreased protein solubility but improved in vitro protein digestibility. Mixograph absorption of wheat and legume flour blends increased from 50–52% for raw legumes to 68–76, 62–64, and 74–80% for cooked, roasted, and fermented ones, respectively. Bread dough with cooked or roasted legume flour was less sticky than that with raw or fermented legume flour. Loaf volume of bread baked from wheat and raw or roasted legume flour blends with or without gluten addition was consistently highest for chickpeas, less for peas and lentils, and lowest for soybeans. Roasted legume flour exhibited more appealing aroma and greater loaf volume of bread than cooked legume flour, and it appears to be the most appropriate preprocessing method for incorporation into bread.     

Thin layer chromatographic determination of aflatoxins, ochratoxins, sterigmatocystin, zearalenone, citrinin, T-2 toxin, diacetoxyscirpenol, penicillic acid, patulin, and penitrem A.

A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4--5 micrograms/kg; ochratoxin A or ethyl ester A 140--145 micrograms/kg; citrinin 600--750 micrograms/kg; zearalenone, 410--500 micrograms/kg; sterigmatocystin, 140--145 micrograms/kg; diacetoxyscirpenol, 2400--2600 micrograms/kg; T-2 toxin, 800--950 micrograms/kg; patulin, 750--800 micrograms/kg; penitrem A 14,000--14,500 micrograms/kg; penicillic acid 3400--3650 micrograms/kg.     

Glucoraphanin and 4-hydroxyglucobrassicin contents in seeds of 59 cultivars of broccoli, raab, kohlrabi, radish, cauliflower, brussels sprouts, kale, and cabbage

The importance of dietary sulforaphane in helping maintain good health continues to gain support within the health-care community and awareness among U.S. consumers. In addition to the traditional avenue for obtaining sulforaphane, namely, the consumption of appropriate cruciferous vegetables, other consumer products containing added glucoraphanin, the natural precursor to sulforaphane, are now appearing in the United States. Crucifer seeds are a likely source for obtaining glucoraphanin, owing to a higher concentration of glucoraphanin and the relative ease of processing seeds as compared to vegetative parts. Seeds of several commonly consumed crucifers were analyzed not only for glucoraphanin but also for components that might have negative health implications, such as certain indole-containing glucosinolates and erucic acid-containing lipids. Glucoraphanin, 4-hydroxyglucobrassicin, other glucosinolates, and lipid erucic acid were quantified in seeds of 33 commercially available cultivars of broccoli, 4 cultivars each of kohlrabi, radish, cauliflower, Brussels sprouts, kale, and cabbage, and 2 cultivars of raab.     

Distribution of Zinc,Manganese, Copper,Cobalt, and Nickel in Andosols Profiles

The distribution of zinc, manganese, copper, cobalt, and nickel in Andosols was investigated. Sixty nine soil samples were collected from different horizons of an Andosols profile in Miyakonojo Basin in south Kyushu, Japan, The total contents of heavy metals were determined by digestion and four extraction solutions, 1 M NH₄Ac (ammonium acetate) pH 4.5, 0.1 M HCl, 0.01 M EDTA (ethylenediaminetetraacetic acid) pH 6.5, and 0.005 M DTPA (diethylenetri-aminepentaacetic acid) pH 7.3 were used to determine the contents of available Zn, Mn, Cu, Co, and Ni in Andosols in relation to the organic carbon content. The results of the extraction analysis showed that by the use of 0.1 M H Cl high value of extracted heavy metals in the upper layers of the humus horizons were obtained while EDTA extraction yielded a large amount of the above mentioned metals in the high humus horizons. The extractable heavy metals contents were high and these metals closely related to the organic carbon content mostly in the humus horizons in the profile. Where, biocycling process may play an important role in the concentration of heavy metals. Based on the study, it was found that the total content of Zn increased towards the C horizons or pumice layers in the soil profile. Such a trend was also found in the case of the Mn content. While the Cu content in the humus horizons was much higher in the upper part of each humus horizon. According to this study the distribution of heavy metals, Cu (organic matter complexes) in the Andosols profile was more stable than that of Zn (organic matter complexes) in soils. It was shown that Zn in the surface humus horizon was enriched but that some amount was leached under buried conditions. The same phenomenon was also observed in the distribution of Mn in the profile. The movement of Co and Ni in the soil profile was limited, as evidenced by the sharp reduction in the concentrations of these two metals in buried soils.

Hence, it is concluded that the distribution of Zn, Mn, Cu, Co, and Ni was considerably higher in the humus horizons of the Andosols profiles.     

Hydrophilic chromatographic determination of carnosine, anserine, balenine, creatine, and creatinine

A new HPLC procedure based on hydrophilic interaction chromatography (HILIC) has been developed for the simultaneous determination of carnosine, anserine, balenine, creatine, and creatinine in meat. This is the first time that HILIC has been directly applied to the study of meat components, having the advantage of not requiring complex cleanup and/or sample derivatization procedures. The chromatographic separation has been developed using a silica column (4.6 x 150 mm, 3 microm), and the proposed methodology is simple, reliable, and fast (<13 min per sample). The method has been validated in terms of linearity, repeatability, reproducibility, and recovery and represents an interesting alternative to methods currently in use for determining the mentioned compounds and other polar substances. The detection limits are 5.64, 8.23, 3.66, 3.99, and 0.06 microg/mL for carnosine, anserine, balenine, creatine, and creatinine, respectively.     

Fluxes of Cu,Zn, Pb,Cd, Cr,and Ni in temperate forest ecosystems

The literature on the fluxes of six heavy metals in temperate forest ecosystems is reviewed. Special attention is given to wet and dry deposition and internal flux, to metal budgets for ecosystems and soils, to concentrations in aqueous compartments of the ecosystem and to speciation in soil solutions. Metal fluxes are discussed in relation to pollution load, soil type, tree species and land use. The mobility of Cu and Pb is strongly dependent on the solubility of organic matter. These metals are commonly accumulated in forest soils. Zinc, Cd and Ni are greatly influenced by soil acidity and are often lost in considerable amounts from acidified soils. Chromium is often at balance in forest ecosystems. Implications for metal solubility and budgets in forest soils are discussed in connection with an increase in soil acidification.     

Estimation of Reference Values for Cadmium,Cobalt, Chromium,Copper, Nickel,Lead, and Zinc in Brazilian Soils

Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log₁₀. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.