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1.
Data are presented for 32 elements (Li, Be, B, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ge, As, Rb, Sr, Y, Zr, Mo, Ag, Cd, Sb, Cs, Ba,
La, Ce, Pr, Nd, Sm, Hf, Tl, Pb, Bi) in organic-rich surface soils in Norway, based on samples from 464 sites. By considering
geographical distributions based on isopleths, results from factor analysis, and ANOVA of median values from 12 different
geographical regions, the contributions from natural and anthropogenic sources are estimated for each element. Long-range
atmospheric transport of pollutants from areas out of Norway is a dominant source for Cd, Sb, Pb, and Bi and also a strongly
contributing factor for Zn, As, Mo, and Tl. Also V, Ni, Cu, and Ge are somewhat affected, but other factors dominate for these
elements. Local point sources of pollution provide significant contributions to soil concentrations of Ni, Cu, Zn, As, Mo,
and Cd. The local bedrock is the overriding source of Li, Be, Ti, V, Cr, Mn, Rb, Zr, Cs, Ba, REE, Hf, and probably of Ge and
Ag. Surface enrichment by root uptake in plants and return to the soil surface by decaying plant material is particularly
evident for Mn, Zn, Rb, Cs, and Ba. These elements show no clear difference between south and north in the country, indicating
that their plant uptake does not depend on latitude. In the case of B and Sr, atmospheric deposition of marine aerosols is
an important source. Rb and Ag, and to a less extent Mn, Ga, and Ba, appear to be depleted in soils near the coast presumably
due to cation exchange with airborne marine cations. 相似文献
2.
紫色土施氮对莴笋营养效应的研究 总被引：10，自引：2，他引：10
3种紫色土施用化学氮肥盆栽莴笋的研究结果表明,石灰性紫色土莴笋生长状况最差,施中、高氮明显降低其株高、根重和茎、叶产量,而中性紫色土施氮的生物效应最佳。酸性紫色土莴笋叶片((NO3--N)/(TN)100)值最低、((AAN)/(TN)100)值最高;植株氮素表观利用率为中性土酸性土石灰性紫色土。中性、酸性和石灰性紫色土施氮分别为133、67、67mg/kg土时,莴笋3个生长期叶片N/P、N/K、K/P值变异系数(C.V％)小,生物量高。施氮显著提高中性和石灰性紫色土莴笋叶片NRA(r值0.9275*～0.9956* *),降低CAT活性和Vc含量,使茎中(△NO3-)/(△FN)值高于酸性紫色土2～5倍,但却提高酸性紫色土莴笋水溶性氨基酸、粗蛋白和可溶性糖含量,改善其食用价值。 相似文献
3.
《Pedobiologia》2014,57(3):123-130
Sterilized soils are frequently used in experiments related to soil biology. Soil sterilization is known to alter physicochemical characteristics of soil, plant growth and community structure of the newly developed bacterial population. However, little information exists regarding soil sterilization effects on belowground processes mediated through root–microbe–soil interactions, e.g., development of rhizosheaths which significantly promote the plant growth under stress environments. The present study was conducted to elucidate effects of soil sterilization on wheat root growth and formation of rhizosheaths in relation to chemical changes caused by soil sterilization and the proportion of expolysaccharide (EPS)-producers in bacterial population recolonizing the sterilized soils. Wheat plants were grown for two weeks under greenhouse conditions either in the unsterilized soil or in soils sterilized by autoclaving (121 °C, 1 h) or by gamma (γ)-irradiation (50 kGy). While soil sterilization had no effect on the release of macronutrients, both sterilization procedures significantly increased the electrical conductivity, water-soluble carbon and DTPA-extractable Mn. Seedlings grown in sterilized soils produced higher root biomass and the rhizosheath soil (RS) mass as compared to those grown in the unsterilized soil. Soil sterilization also increased the root length, surface area, volume and number of tips. In bulk soil, RS and on roots, the proportion of EPS-producers in the total bacterial population was higher in sterilized treatments than in the unsterilized. Amending the unsterilized soil with glucose-C increased the root biomass, whereas adding Mn II increased the RS mass. The results showed that soil sterilization by autoclaving or γ-irradiation increases the root growth and RS mass of wheat seedlings. The water-soluble C and DTPA-extractable Mn released upon sterilization, and the increased proportion of EPS-producers in the bacterial population recolonizing the sterilized soils were involved in the observed effects. The results may have implications in studies using autoclaved or γ-irradiated soils to investigate soil–plant–microbe interactions and signify the need to account for intrinsic stimulatory effects of soil sterilization. 相似文献
4.
H. H. Reber 《Biology and Fertility of Soils》1989,7(2):152-157
Summary Inconsistent results were obtained from comparative studies on the impact of increasing Cd contamination in three soils on growth of spring-wheat plantlets and soil respiration. With identical soil Cd loads, plant growth was increasingly inhibited in the following sequence: Neutral sandy hortisol (pH 7.0) < phaeosem (pH 6.9) < acidic cambisol (pH 5.6), suggesting a strong dependence on pH. In contrast, oxidation of a glucose-glutamate mixture by these soils was increasingly inhibited in the sequence: Acidic cambisol < neutral sandy hortisol < phaeosem. Inhibition of plant growth was correlated with the extractability of Cd from soils by 0.1 M CaCl2. However, comparison of dose-response curves with dose-extractability and dose-uptake curves suggested the presence of a soil factor that modified plant uptake of available Cd. This factor, possibly the concentration of antagonistic cations, was apparently also active within the plants. The inconsistency in the responses of plant growth and of soil respiration with respect to the soil Cd load was ascribed to microbiological soil properties exceeding the importance of Cd availability. Relatively high in vitro sensitivity of prokaryotes and their biochemical interdependence together with relatively high diversities of streptomycetes and fungi were paralleled by a relatively strong inhibition of soil respiration. 相似文献
5.
稻壳基生物炭对生菜Cd吸收及土壤养分的影响 总被引：14，自引：1，他引：14
探讨稻壳基生物炭对Cd污染土壤上叶菜吸收Cd和土壤Cd形态的影响作用,明确稻壳基生物炭对土壤Cd污染的调控效应,可为合理利用稻壳基生物炭降低叶菜Cd含量提供参考。采用盆栽试验,研究了稻壳基生物炭在不同用量水平下对2茬生菜地上部Cd含量、土壤养分含量及Cd赋存形态的影响。结果表明,在5~25 g-kg-1用量范围内,稻壳基生物炭显著降低了2茬生菜地上部和根系Cd含量,且在最大用量25 g-kg-1时效果最好,地上部Cd含量分别比未施稻壳基生物炭的对照处理降低了19.6%和45.8%,根系Cd含量分别降低了36.8%和28.0%。在25 g-kg-1用量水平下,稻壳基生物炭对土壤p H、有效磷、速效钾及有机质含量提升效果明显,但显著降低了土壤碱解氮含量。施加稻壳基生物炭对土壤有效态Cd含量及Cd化学形态也有不同影响。随着稻壳基生物炭用量的增加,土壤NH4OAc提取态Cd含量和弱酸提取态Cd含量显著降低,在用量为25 g-kg-1时,分别比对照降低17.9%和10.4%,可还原态Cd含量无显著变化,可氧化态Cd含量呈减低趋势,残渣态Cd含量增加17.6%。因此推测,提升土壤p H、降低土壤有效态Cd含量、增加残渣态Cd含量可能是稻壳基生物炭降低生菜体内Cd含量的主要原因。稻壳基生物炭可以作为土壤改良剂,抑制Cd污染土壤上叶菜对Cd的吸收,改善土壤养分状况。 相似文献
6.
Rola M. Atiyeh Clive A. Edwards Scott Subler James D. Metzger 《Compost science & utilization》2013,21(3):215-223
We germinated and grew tomato, pepper, lettuce, and marigold seedlings in a standard commercial soilless plant growth medium (Metro-Mix 360), and in coir/perlite and peat/perlite-based container media substituted with 10% or 20%, by volume, of vermicompost derived from pig manure or food wastes. Half of the treatments were watered with liquid inorganic fertilizer while the other half received only water. Germination rates of tomato, pepper, lettuce, and marigold seeds in the coir/perlite mixture did not differ significantly from that in Metro-Mix 360. However, the germination rate of tomato, pepper and lettuce seedlings was very low in the peat/perlite mixture. Substituting some of the peat/perlite mixtures with equal amounts of vermicomposts, particularly pig manure vermicompost, enhanced germination rates greatly, making it comparable to that in the commercial medium (Metro-Mix 360). Pepper, lettuce, and marigold seedlings grown in Metro-Mix 360, which already contains a starter nutrient fertilizer in its formulation, had greater root and shoot dry weights than those grown in the control media (coir/perlite mix and peat/perlite mix). Substituting coir/perlite and peat/perlite mixtures with 10% or 20% of either vermicompost enhanced the growth of seedlings significantly, resulting in an overall plant growth as good as and sometimes better than that in Metro-Mix 360. When the plants were provided daily with a complete fertilizer solution, marigold seedlings in peat-based substrate with 20% pig waste vermicompost, and lettuce seedlings in both coir and peat-based substrates, mixed with 20% food wastes vermicompost, produced greater shoot dry weights than those grown in the commercial potting medium. The growth enhancements tended to be greater in peat/perlite-based mixes than in coir/perlite-based mixes, more so with the addition of pig manure vermicompost than with food waste vermicompost. Earthworm-processed pig manure and food wastes would be suitable materials for inclusion into the formulation of soilless potting media, since substitution of these media with relatively low concentrations of vermicomposts can promote plant growth. 相似文献
7.
Metal pollution is an important concern because of its potential to affect human health. Metals such as lead and cadmium can enter soil via the food chain and exceed normal limits, producing harmful effects. In this study, six common garden and residential plant species were grown in soils from Spelter, WV, USA, contaminated with a variety of metals including lead (Pb), zinc (Zn), cadmium (Cd), and copper (Cu). Plant species included radish, carrot, chicory, spinach, lettuce, and clover. Metal concentrations in plant tissues were compared with metal concentration in soil by a multi‐step chemical extraction. The largest accumulation of Pb (126 mg kg−1) and Zn (1493 mg kg−1) was seen in radish roots, with Cd (40 mg kg−1) having the largest accumulation in carrot roots. Comparisons of plant availability with soil chemical extractions indicated that the combined soluble and exchangeable fractions could estimate available Zn and Cd for all six plant species. For Pb and Cu, however, the comparisons indicate that these two elements were not readily available in Spelter soils. A health risk assessment was carried out for residents at Spelter on the basis of edible tissue concentrations and publicly available consumption data. Uptake of Cd by carrot roots was about five times more than the regulatory limits for men, eight times more for women, and 12 times more for children. On the basis of the results, carrot and lettuce grown in these soils have the potential to cause toxicological problems in men, women, and young children resulting from Cd and Zn accumulation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
生物氢烷工程沼渣用于油菜及菠菜育苗的效果 总被引：5，自引：3，他引：2
为探究将生物氢烷工程沼渣应用于蔬菜育苗基质生产的可行性,以油菜品种"华绿四号"、菠菜品种"先锋菠菜"为材料,按不同体积比将生物氢烷工程沼渣与土壤或草炭、蛭石和珍珠岩三者混配作为育苗基质,通过穴盘育苗试验研究生物氢烷工程沼渣对基质理化性质和油菜、菠菜幼苗生长的影响。结果表明:添加生物氢烷工程沼渣可显著改善基质的容重、总孔隙度、有机质含量、pH值和电导率EC(electronical conductivity)值等理化性质;适宜配比的生物氢烷工程沼渣对幼苗生长发育有一定的促进作用,其中T6(生物氢烷工程沼渣20%、草炭30%、蛭石25%、珍珠岩25%)的基质配方较为适宜,T6中油菜出苗率显著高于CK3(草炭50%、蛭石25%、珍珠岩25%)(P0.05),提高了14.3%,菠菜出苗率提高了12.4%,幼苗的株高、茎粗、单株叶面积显著高于或接近CK3(P0.05),幼苗根冠比和壮苗指数与CK3无显著差异;添加生物氢烷工程沼渣可使幼苗地下部生物量显著升高(P0.05),促进根系生长,使幼苗地上部、地下部生物量分配更加均衡。因此,生物氢烷工程沼渣具有一定的肥效,可部分替代草炭用于叶菜育苗基质生产,但使用前可考虑进行好氧堆肥处理进一步腐熟或与氮肥配施以提高肥效。 相似文献
9.
SHENTU Jia-Li HE Zhen-Li ZENG Yan-Yan HE Shan-Ying DU Shao-Ting SHEN Dong-Sheng 《土壤圈》2014,24(4):553-562
The effects of root activity on microbial response to cadmium （Cd） loading in the rhizosphere are not well understood. A pot experiment in greenhouse was conducted to investigate the effects of low Cd loading and root activity on microbial biomass and community structure in the rhizosphere of pakchoi （Brassica chinensis L.） on silty clay loam and silt loamy soil. Cd was added into soil as Cd（NO3）2 to reach concentrations ranging from 0.00 to 7.00 mg kg-1. The microbial biomass carbon （MBC） and community structure were affected by Cd concentration, root activity, and soil type. Lower Cd loading rates （〈 1.00 mg kg-1） stimulated the growth of pakchoi and microorganisms, but higher Cd concentrations inhibited the growth of microorganisms. The content of phospholipid fatty acids （PLFAs） was sensitive to increased Cd levels. MBC was linearly correlated with the total PLFAs. The content of general PLFAs in the fungi was positively correlated with the available Cd in the soil, whereas those in the bacteria and actinomycetes were negatively correlated with the available Cd in the soil. These results indicated that fungi were more resistant to Cd stress than bacteria or actinomycetes, and the latter was the most sensitive to Cd stress. Microbial biomass was more abundant in the rhizosphere than in the bulk soil. Root activity enhanced the growth of microorganisms and stabilized the microbial community structure in the rhizosphere. PLFA analysis was proven to be sensitive in detecting changes in the soil microbial community in response to Cd stress and root activity. 相似文献
10.
Geebelen Wouter Vangronsveld Jaco Adriano Domy C. Carleer Robert Clijsters Herman 《Water, air, and soil pollution》2002,140(1-4):261-277
Lead immobilization was evaluated on soils spiked with increasingconcentrations of Pb (as Pb-acetate) using the following soilamendments: bentonite, zeolite, cyclonic ash, compost, lime,steelshot, and hydroxyapatite. The immobilization efficacy of theamendments was evaluated according to the following criteria:Ca(NO3)2-extractable Pb as an indicator of Pbphytoavailability, morphological and enzymatic parameters of beanplants (Phaseolus vulgaris) as indicator of phytotoxicity, and Pb concentration in edible tissue of lettuce (Lactuca sativa). The lowest reductions in Ca(NO3)2-extractablesoil Pb occurred when bentonite and steelshot were applied. Phytotoxicity from application of steelshot was confounded by toxic amounts of Fe and Mn released from the by-product which killed the lettuce seedlings. Addition of zeolite induced poorplant growth independent of Pb concentration due to its adverseeffect on soil structure. Substantial reductions in Ca(NO3)2-extractable Pb were observed when cyclonic ash, lime, compost and hydroxyapatite were applied. In general,these amendments reduced Pb phytotoxicity concomitant with reduced Pb concentration in lettuce tissue. Cyclonic ash, limeand compost further improved plant growth and reduced oxidativestress at low soil Pb concentrations due to soil pH increase mitigating Al or Mn toxicity. 相似文献
11.
Gloria N. Egwu 《Archives of Agronomy and Soil Science》2013,59(6):875-887
Urban and peri-urban agriculture in dry semi-arid northern Nigeria relies on untreated wastewater for all-year irrigation and the production of vegetables for urban markets. Human and animal exposure to potentially toxic metals is attributed to the consumption of vegetables raised in metal-polluted soils. The objective of this study was to determine the bioavailability and soil–plant transfer of Cd, Pb and Zn to amaranthus (Amaranthus caudatus) and lettuce (Latuca sativa) raised in the garden fields and to assess their safety for human consumption. Ten farmers’ fields were selected per location for analysis of Cd, Pb and Zn in soils and vegetables. Whereas total concentrations of Cd and Zn were greater than the safe or permissible limits for agricultural soils, the Pb concentration was less than its maximum allowable concentration. However, the concentration of Pb and Cd in edible portions of amaranthus exceeded the safe limit for human consumption by 7–13 times, while lettuce exceeded the limit by 11–17 times. Cadmium was more rapidly transferred from soil through root to shoot than Zn > Pb. The plant tissue concentrations of the metals were not significantly correlated with the Diethylene triamine pentaacetic acid (DTPA) and dilute CaCl2-extractable concentrations of the metals in the soils. Furthermore, permissible limit of Pb established as standards for agricultural lands may not be suitable to ensure produce safety in Urban and peri-urban agriculture (UPA) in the city of Kano. 相似文献
12.
The most likely means of Be entry into the food chain would appear to be via root, tuber, and forage crops grown on acid soils. Potatoes (Solanum tuberosum) and oats (Avena sativa) were grown in greenhouse pots of a strongly acid soil treated with 0 to 300 ppm Be and 0 to 1000 ppm CaC03. Germination and yield decreased, and plant Be content increased, with increasing soil Be content. The Be content of the potato tubers appeared to be low and unaffected by the soil Be content. Liming the soil and increasing the time between Be contamination and crop planting lessened the effect of Be. 相似文献
13.
Maryam Zahedifar Somayeh Dehghani Edris Gavili 《Archives of Agronomy and Soil Science》2017,63(1):136-149
Continuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties. 相似文献
14.
《Communications in Soil Science and Plant Analysis》2012,43(13-14):2409-2437
Abstract Incineration reduces sewage sludge volume, but management of the resulting ash is an important environmental concern. A laboratory incubation study and greenhouse pot experiments with lettuce (Lactuca sativa L.) and corn (Zea mays L.) were conducted to examine the potential for recycling elements in sewage sludge incinerator ash in agricultural systems. Ash rates in both the laboratory and greenhouse were 0, 0.95, 3.8, 15.2, and 61.0 g/kg soil (Typic Hapludoll). Ash was also compared to equivalent rates of citrate soluble P from superphosphate fertilizer in a soil‐less growth medium. During soil: ash incubation, Olsen P and DTPA extractable copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) increased with incubation time at the higher ash rates. Release rates diminished rapidly, however, and the limited release of these elements after 280 days was associated with decreasing pH. In the greenhouse, ash amendment increased extractable soil P, plant tissue P, and the growth of lettuce and corn. Ash was a less effective P source than superphosphate fertilizer in the soil‐less growth medium and Olsen P levels were more consistent with these differences than Bray P. Ash increased extractable soil levels and plant tissue concentrations of calcium (Ca), magnesium (Mg), sodium (Na), Cu, and Zn, but extractable soil manganese (Mn) and plant tissue Mn decreased. Ash increased soil pH and extractable SO4‐S. DTPA extractable Cd and Pb increased, but chromium (Cr) and nickel (Ni) decreased. Lettuce accumulated higher amounts of these trace metals than corn, but tissue concentrations were at control levels or below detection limits in both crops. 相似文献
15.
Bashar Qasim Mikael Motelica-Heino Sylvain Bourgerie Arnaud Gauthier Domenico Morabito 《Journal of Soils and Sediments》2016,16(3):811-820
Purpose
This study aimed at investigating the rhizosphere effects of Populus euramericana Dorskamp on the mobility of Zn, Pb and Cd in contaminated technosols from a former smelting site.Materials and methods
A rhizobox experiment was conducted with poplars, where the plant stem cuttings were grown in contaminated technosols for 2 months under glasshouse conditions. After plant growth, rhizosphere and bulk soil pore water (SPW) were sampled together. SPW properties such as pH, dissolved organic carbon (DOC) and total dissolved concentrations of Zn, Pb and Cd were determined. The concentrations of Zn, Pb and Cd in plant organs were also determined.Results and discussion
Rhizosphere SPW pH increased for all studied soils by 0.3 to 0.6 units compared to bulk soils. A significant increase was also observed for DOC concentrations regardless of the soil type or total metal concentrations, which might be attributed to the plant root activity. For all studied soils, the rhizosphere SPW metal concentrations decreased significantly after plant growth compared to bulk soils which might be attributed to the increase in pH and effects of root exudates. Zn, Pb and Cd accumulated in plant organs and the higher metal concentrations were found in plant roots compared to plant shoots.Conclusions
The restricted transfer of the studied metals to the plant shoots confirms the potential role of this species in the immobilization of these metals. Thus, P. euramericana Dorskamp can be used for phytostabilization of technosols.16.
石灰性土壤中锰素营养的研究——Ⅱ.土壤有效锰的测定 总被引：2，自引：0，他引：2
自从Leeper[5]首先提出用对苯二酚提取土壤易还原态锰评价土壤供锰状况以来,四十多年间各国的土壤农化工作者陆续设计并使用了种类繁多的土壤有效锰的提取剂。将其归纳大致可分为五类。 相似文献
17.
R. L. F. Fontes J. M. N. Pereira J. C. L. Neves M. P. F. Fontes 《Journal of plant nutrition》2013,36(5):884-901
Lettuce (Lactuca sativa L.) and dry beans (Phaseolus vulgaris L.) were grown in three Brazilian Red-Yellow Latossols (Oxisols) in greenhouse conditions with cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), and nickel (Ni) applied to soils in treatments arranged as a randomized complete block design. Plant metals were analyzed in lettuce shoots and dry beans roots, stems, leaves, and seeds. After plant growth, soil samples from the pots were extracted with Mehlich-3 (M-3) for metal availability evaluation. The release of Ni in the M-3 extraction was dependent on the soil exchangeable aluminum (Al3 +). Mehlich-3 was efficient for determination of availability of Cd, Pb, Cu, Zn, and Ni for dry beans and availability of Cd and Ni for lettuce. The dry bean leaves Cd, Pb, Cu, Zn, and Ni were highly correlated with their recovering from soils with M-3. The same was observed for Cd and Ni in lettuce shoots and the M-3 recovered metals from soils. 相似文献
18.
Wenhao Yang Taoxiang Zhang Siliang Li Wuzhong Ni 《Journal of Soils and Sediments》2014,14(8):1385-1396
Purpose
Effects of phytoextraction by Sedum alfredii H., a native cadmium hyperaccumulator, on metal removal from and microbial property improvement of a multiple heavy metals contaminated soil were studied under greenhouse conditions.Materials and methods
A rhizobox experiment with an ancient silver-mining ecotype of S. alfredii natively growing in Zhejiang Province, China, was conducted for remediation of a multiple heavy metals contaminated soil. The rhizobox was designed combining the root-shaking method for the separation of rhizospheric vs near-rhizospheric soils and prestratifying method for separation of sublayers rhizospheric soils (0–10 mm from the root) and bulk soil (>10 mm from the root). Soil and plant samplings were carried out after 3 and 6 months of plant growth.Results and discussion
Cadmium (Cd), zinc (Zn), and lead (Pb) concentrations in shoots were 440.6, 11,893, and 91.2 mg kg?1 after 6 months growth, and Cd, Zn, and Pb removed in the shoots were 0.862, 25.20, and 0.117 mg/plant. Microbial biomass C, basal respiration, urease, acid phosphatase, and invertase activities of the rhizospheric soils were significantly higher than that of unplanted soils after 6 months growth. Microbial biomass carbon (MBC) of 0–2 mm and basal respiration (BR) rate of 0–8 mm sublayer rhizospheric soils were significantly higher than that of bulk soil after 6 months growth. So were the three enzyme activities of 0–4 mm sublayer rhizospheric soils. BR rate and urease were significantly negatively correlated with soluble Cd, so were MBC, acid phosphatase, and intervase activities with soluble Zn, MBC, BR rate, and three enzyme activities with soluble Pb.Conclusions
Harvesting shoots of S. alfredii could remove remarkable amounts of Cd, Zn, Pb, and lower water-soluble Cd, Zn, and Pb concentrations in the rhizospheric soils. MBC, BR rate, and enzyme activities of the metal polluted soil, especially the rhizospheric soils increased with phytoextraction process, which is attributed to the stimulation of soil microbes by planting as well as the decrease in soil-soluble metal concentration. 相似文献19.
20.
《Communications in Soil Science and Plant Analysis》2012,43(7-8):1124-1137
The rate of cadmium (Cd) uptake by lettuce (Lactuca savita var. longifolia) over an entire growing season was investigated in a field treated with phosphorus (P) fertilizers spiked to different Cd levels. Romaine lettuce was planted following the standard cultivation practices. Over the growing period, soil and plant samples were taken to determine the total soil Cd content, Cd concentration of 1:0.5 (soil‐to‐water) extracts, and Cd content of plant tissue. Results indicated that lettuce can accumulate as much as 20 mg Cd per kilogram dry biomass without adverse effects on growth. The Cd content in the plant tissues decreased exponentially with time, indicating a dilution factor existing along with the plant growth. The plant uptake rate on a per‐unit‐area basis increased over time and can be simulated by a sigmoid pattern model. The plant uptake coefficient (α, L solution kg biomass?1 day?1) decreased as the Cd treatment level increased. 相似文献