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1.
As, Cd, Cu, Pb, Sb and Zn concentrations were determined in two earthworm species (Allolobophora rosea and Nicodrilus caliginosus) from a mining and industrial area in northern Kosovo and compared with their contents in the bulk soil and the main soil fractions. Earthworm specimens were collected at fifteen sites located at different distances from a Pb–Zn smelter along a gradient of decreasing contamination. Individuals of A. rosea and N. caliginosus showed similar tissue levels of As, Cd, Cu, Pb, Sb and Zn, suggesting that earthworm species belonging to the same eco-physiological group have a similar propensity to uptake and bioaccumulate heavy elements. Cd, Pb, Sb and Zn concentrations in both earthworm species were positively correlated with the respective total soil contents and generally decreased with distance from the smelter. The bioaccumulation factor (BAF) revealed that Cd and Zn were the only elements bioaccumulated by earthworms. The rank order of BAF values for both species was as follows: Cd > > Zn > > Cu > As = Pb = Sb. The absorption of Cd, Pb, Sb and Zn by earthworms mostly depended on the extractable, reducible and oxidable soil fractions, suggesting that the intestine is likely the most important uptake route. The extractable soil fraction constantly influenced the uptake of these heavy elements, whereas the reducible fraction was important mainly for Pb and Zn. The water soluble fraction had an important role especially for the most mobile heavy elements such as Cd and Zn, suggesting that dermal uptake is not negligible. As a whole, the analytical data indicate that soil fractionation patterns influence the uptake of heavy elements by earthworms, and the extractable fraction is a good predictor of heavy element bioavailability to these invertebrates in soil.  相似文献   

2.
M. J. KHAN  D. L. JONES 《土壤圈》2009,19(5):631-641
Soil samples from a historic copper mine tailing site at the Parys Mountain,North Wales (UK) were amended with green waste compost (GC),GC+30% sewage sludge (GCS),lime and diammonium phosphate (DAP),to determine the effect of amendments on DTPA-and Ca (NO3) 2-extractable metals in the mine tailing and on the phytoavailability of heavy metals by a lettuce (Lactuca sativa L.).Both compost were added at the rate of 10% by weight,lime was added as calcium carbonate equivalent (pH = 7) and DAP at a 2300 mg kg-1 soil level.The experiment was arranged in randomised complete design with three replicates in pots under control environment.Addition of lime resulted in the largest reduction in metal extractability with DTPA and Ca (NO3) 2 and phytoavailability of Cu,Fe and Zn while DAP was effective in lowering Pb extractability and phytoavailability.With exception of Zn,all other metals extracted decreased with time after amendment applications.The distribution of heavy metals between and within the four procedures of potentially bioavailable sequential extraction (PBASE) varied significantly (P < 0.001).Stronger relationships were noted between the metals extracted with PBASE SE1 and Cu,Pb (P < 0.01) and Fe (P < 0.001) in the lettuce.These results indicate that addition of lime is sufficient to restore the vegetative cover to a high metal mine waste while DAP is good for stabilizing Pb,but its detrimental role on plant growth and the risk associated with presence of N in DAP (through N leaching) may restrict its chances for remediation of contaminated sites.  相似文献   

3.
Phosphate rock (PR) was activated via acidulation with HCl, EDTA, and oxalic acid to enhance its reactivity. The release, lateral transport, and uptake of phosphorus (P) along with trace metals from pristine and activated PRs were investigated in a soil micro-block system over a period of 27 days, using wheat (Triticum aestivum L.) plants. Significantly (p < 0.05) higher amounts of available soil P, Fe, Mn, and Zn were released from all the PRs after application to soil within first 9 days of seedling transplantation, while the release of other trace metals (Cd, Co, Cr, Cu, Ni, and Pb) was minimal (<1.2 mg kg?1). On cumulative basis, APR-O (oxalic acid activated PR) was the most efficient amendment releasing 164% more available P, followed by APR-E (EDTA activated PR) releasing 130% more available P, compared to the pristine PR. Similar results were also observed in the release of available Fe, Mn, Zn, and other trace metals. The highest diffusive mass fluxes for available P, Mn, Fe, and Zn in soil were observed after 3 days of seedling transplantation, which reduced subsequently. The uptake of P, Fe, Mn, and Zn by wheat plants was increased by 394%, 715%, 92%, and 91%, respectively, in APR-O application compared to the pristine PR, while it was increased by 280%, 188%, 16%, and 27%, respectively, in APR-E application compared to the pristine PR. Subsequently, APR-O and APR-E amendments resulted in enhanced shoot lengths, root lengths, shoot dry matter, and root dry matter contents of wheat plants. Hence, it was concluded that activation of PR with oxalic acid and EDTA prior to direct soil application may enhance the reactivity of PR and could serve as a cost-effect fertilization strategy for higher wheat crop production.  相似文献   

4.
The objective of this study was to compare the residual effect of zinc (Zn) from three Zn chelates (Zn‐aminelignosulfonate, Zn‐AML; Zn‐polyhydroxyphenylcarboxylate, Zn‐PHP; and Zn‐ethylenediaminedisuccinate, Zn‐EDDS), applied at two rates (5 and 10 mg Zn [kg soil]–1, respectively) to a previous crop, for a flax crop (Linum usitatissimum L.). For the greenhouse experiment, two different soils were used: a weakly acidic soil, classified as Typic Haploxeralf (Soilacid), and a calcareous soil, classified as Typic Calcixerept (Soilcalc). Plant availability of soil Zn was evaluated using the DTPA‐triethanolamine (TEA), Mehlich 3, and low‐molecular‐weight organic acids (LMWOAs) methods. Easily leachable Zn was determined, and soil Zn status was characterized based on the Zn distribution in different fractions obtained by a sequential extraction. The Zn reserves after the previous crop were substantial and ranged from 2.85% to 5.61% of available Zn (Mehlich 3‐extractable) with respect to the applied Zn. Plant parameters such as dry‐matter yield, total Zn, and soluble Zn concentrations were measured, and Zn utilization by plants was calculated. In both soils, the highest concentrations of available Zn were associated with the application of Zn‐AML at a rate of 10 mg Zn kg–1. In Soilacid the largest quantity of easily leachable Zn was also observed with Zn‐AML fertilizer. Similarly, Zn‐AML resulted in the highest Zn concentration in flax seeds (229 mg Zn kg–1 and 72 mg Zn kg–1 for the highest rate of Zn application to Soilacid and Soilcalc, respectively). The results suggest that these Zn chelates resulted in a residual effect in soils with appropriate concentrations of the most labile fractions of Zn and available Zn, particularly when Zn‐AML was applied at the highest rate. This chelate was more effective in Soilacid than in Soilcalc. In the weakly acidic soil at the lowest Zn level it was associated with the highest percentage of Zn utilization by the flax plant and the most effective Zn transfer from soil to the plant.  相似文献   

5.
A total of 222 surface soil samples and 40 plant samples were collected to investigate the spatial distribution and possible sources of soil heavy metals and to know the uptake and translocation of heavy metals from roots to different plant parts in a representative vegetable production area in the Baguazhou Island, a suburb of Nanjing City, East China. The arithmetic mean values of total Cd, Cr, Cu, Ni, Pb, and Zn concentrations in the soils were 0.314, 133, 41.0, 58.0, 31.8, and 114 mg kg-1, respectively. All of these values were above the topsoil background values in the Nanjing area. Multivariate and geostatistical analyses showed that soil Cd contamination was derived mainly from agricultural practices. In contrast, Cu and Zn were derived mainly from soil parent materials and Pb from atmospheric deposition from highway gasoline stations. Artemisia selengensis, a locally important specialty vegetable, accumulated heavy metals primarily in the edible leaves. The general distribution of heavy metal concentrations in this plant species showed that the highest occurred in the leaves, intermediate in the stems and lowest in the roots. Cd had the highest concentration factor (root-to-soil ratio) and may pose increased health risks in the future to the local population through the consumption of contaminated vegetables.  相似文献   

6.
孙瑞波  盛下放  李娅  何琳燕 《土壤学报》2011,48(5):1013-1020
以南京栖霞重金属污染区5种植物及其根际土壤为研究对象,对植物富集重金属特征以及重金属含量与根际土壤细菌数量、土壤酶活性等的相关性进行了调查分析。结果发现,植物根际重金属污染物以Zn和Cd为主;重金属污染地区的植物有较强的吸收重金属能力,龙葵和茼草具备了超积累植物的基本特征;植物根际细菌和Pb抗性细菌的数量达到了107CFU g-1土;根际土壤酶活性未受到重金属的毒害或受到的毒害很小;植物体中重金属含量与土壤重金属含量及其存在状态、土壤酶、土壤重金属抗性细菌有显著的正相关性。根际土壤细菌尤其是具有重金属抗性的活性细菌可能会促进土壤重金属的活化,由此促进植物体对重金属的吸收和转运。  相似文献   

7.
冬小麦产量结构要素预报方法   总被引:1,自引:2,他引:1  
为优选出最佳的冬小麦产量结构要素预报方法,该研究选择冬小麦成穗数、穗粒数及千粒质量为预报目标,综合考虑种植品种、密度及地区因子,并对气象因子进行膨化统计,得到126个自变量因子,分别采用多元线性回归、因子分析-线性回归及BP(Back Propagation)神经网络等3种方法进行建模分析。结果表明,直接采用各因子进行回归分析无法解决不同自变量间存在的多重共线性问题,而因子分析虽然消除了不同自变量间的多重共线性,但采用因子优化后的10个综合因子分别对3个产量结构要素进行线性回归,得到的预报模型决定系数(R^2)均不足0.500。运用BP神经网络对冬小麦3个产量结构要素进行预报,结果发现,当输入层为126、隐含层为16、输出层为3时,BP神经网络结构最佳,在此结构下,模型的决定系数为0.644,明显优于多元线性回归及因子分析-线性回归法。同时,基于BP神经网络模型对冬小麦产量结构要素的预报精度平均达85.3%。因此,推荐采用BP神经网络模型对冬小麦产量结构要素进行预报。  相似文献   

8.
农作物叶片对大气沉降重金属的吸收转运和积累机制   总被引:2,自引:0,他引:2  
近年来,农产品的重金属超标问题已经引起了公众的广泛关注,也是国内外学者研究的热点.要实现农产品重金属污染的有效防控,首先需要解决的就是重金属来源问题.目前已有的研究大多集中在根系对土壤中重金属的吸收机制研究,且已基本探明作物根系对重金属的吸收转运机制,包括根际离子的活化,根细胞的吸附和扩散、跨膜运输,根皮层细胞的横向运...  相似文献   

9.
ABSTRACT

Effects of three supplemental calcium (Ca++; 2.5, 5.0, and 10 mole m?3) concentrations on ion accumulation, transport, selectivity, and plant growth of salt-sensitive species, Brassica rapa ‘Sani’ in saline medium were investigated. Supplemental Ca++ in the presence of 125 mol m?3 sodium chloride (NaCl) did not improve the dry weight and leaf area indicating no role played by Ca++ in the alleviation of salinity induced growth inhibition. However, calcium chloride (CaCl2) did significantly affect sodium (Na+), potassium (K+), and Ca++ contents of roots and shoots. The ion contents of shoots were significantly greater than those of roots per g dry weight, indicating ion transportation to shoots is greater than ion accumulation in roots. Use of CaCl2 in 125 mol m?3 NaCl reduced the Na+ content but increased K+ and Ca++ contents in shoots. Sodium contents in shoots differed among the supplemental Ca++ treatments indicating the role of CaCl2 in Na+ ions transportation. Calcium content in shoots declined significantly in the control treatment (0 CaCl2) but increased significantly in 10 mol m?3 CaCl2. The root also showed the effects of Ca++ on the reduction of Na+ content and the increase of K+ and Ca++ content. Unexpectedly, 5 mol m?3 CaCl2 induced the highest Na+ content in roots at 16 days after treatment. Supplemental CaCl2 application influenced the K+ or Ca++ selectivity over Na+ in two ways, ion accumulation at roots and transport to shoots. However, high CaCl2 treatments allowed greater Ca++ selectivity over Na+ than low CaCl2. Likewise, high supplemental CaCl2 showed higher K+ selectivity over Na+ than low CaCl2. A marked increase in K+ versus Na+ selectivity for the transport process occurred at 10 mol m?3 CaCl2 treatments. The roots and shoots exhibited higher K+/Na+ and Ca++/Na+ ratios in high CaCl2 treatment than in low. The results are discussed in context to supplemental Ca++ concentrations, ions accumulation, transportation and selectivity of salt sensitive Brassica rapa cultivar.  相似文献   

10.
Study aims to investigate the effects of vermicomposts containing oil processing wastes, dairy manure, municipal open market wastes and straw on the growth, nutrient concentrations and nutrient uptakes of corn plant. For this, there different mixtures were prepared. Vermicomposts were applied with the rates of 0, 5000, 10000, and 20000 kg ha?1 to 2 kg soil containing pots. Study was conducted in growth chamber for 2 months. Vermicompost applications increased plant growth, some plant nutrient concentrations and uptake. Also, vermicomposts showed the variation on parameters depending on their mixtures. Results showed that nutrients taken by the plant increased with the vermicompost until 10000 kg ha?1 dose. Most of the nutrient concentrations such as phosphorus, potassium, calcium, magnesium, iron, and manganese (P, K, Ca, Mg, Fe, and Mn) were not increased in plant tissues, whereas uptake of them by the plant showed a significant increase. In addition, residual soil nutrients increased with the increase in vermicompost levels.  相似文献   

11.
基于Hydrus-1D模型的玉米根系吸水影响因素分析   总被引:1,自引:1,他引:1  
为探索土壤质地、植物生长状况和气象条件对不同土壤水分条件下根系吸水速率的影响机理,该文以相对根吸水速率与土壤含水率的关系衡量土壤水分有效性,利用Hydrus-1D模型模拟了3种土壤(壤黏土、黏壤土和砂壤土)中不同玉米生长状况(包括叶面积指数、根系深度和根系剖面分布)或蒸发力条件下根系吸水速率随含水率的动态变化,确定了不同条件下根系吸水速率开始降低的临界含水率。结果表明:土壤质地、植物的叶面积指数和根系分布及大气蒸发力都对根系吸水动态曲线的临界含水率有一定影响,其中根系深度和根系分布形状还影响根系吸水速率与含水率关系曲线的形状,但在3种土壤中,根系吸水速率的动态变化对植物生长和大气蒸发力的响应不同。总体而言,3种土壤临界含水率的大小是壤黏土>黏壤土>砂壤土;临界含水率随大气蒸发力的升高而升高,随根系深度和深层根系分布的增加而降低;各因子对玉米根系吸水影响程度的大小是土壤质地>根系分布形状>根系深度>大气蒸发力>叶面积指数。  相似文献   

12.
Abstract. A predictive model of metal concentrations in crops was developed to optimize soil liming and sludge application strategies at a dedicated sewage sludge disposal site. Predictions of metal concentrations in plant tissue were derived from measured values of soil metal concentration, humus content and soil pH. The plant and soil data used to parameterize the model were collected on site using quadrat sampling of mature crop and underlying topsoil. The uptake model was used to map predicted metal concentrations in wheat grain and forage maize based upon a database of soil characteristics (metal content, % humus and pH) measured as part of a routine geochemical survey of the site. The effect of a management strategy to modify uptake of Cd by wheat by changing soil pH was investigated. The effect of soil dust adhering to maize plants at harvest was also simulated to investigate the importance of this pathway for Cd transfer to animal feed such as silage.
The model gave satisfactory predictions for uptake of Cd and Zn but less useful simulations for Pb, Cu and Ni. The results for Cd uptake showed a greater dependence on soil pH in the case of wheat in comparison to maize. It is suggested that, for the study site, liming to pH 7.0 will reduce Cd concentrations in wheat grain to within EC legal standards. However the Cd content of maize may still exceed these guidelines, with a relatively minor contribution from contamination with soil dust.  相似文献   

13.
The resistance of most plants to salt can be impaired by concurrent waterlogging. However, few studies have examined this interaction during germination and early seedling growth and its implications for nutrient uptake. The aim of the study was to examine the response of germination, early growth, and nutrient uptake to salt (NaCl) and hypoxia applied to barley (Hordeum vulgare L. cv. Stirling), in solution culture. Hypoxia, induced by covering seeds with water, lowered the germination from 94% to 28% but salinity and hypoxia together lowered it further to 13% at 120 mM NaCl. While the germination was 75% at 250 mM NaCl in aerated solution, it was completely inhibited at this NaCl concentration under hypoxia. Sodium ion (Na+) concentrations in germinated seedlings increased with increasing salinity under both aerated and hypoxic conditions during germination, while K+ and Mg+ concentrations were decreased with increasing salinity in 6 d old seedlings. After 20 d, control seedlings had the same dry weights of the roots and shoots with and without hypoxia but at 10 mM NaCl and higher, shoot and root dry weight was depressed with hypoxia. Sodium ion increased in roots and shoots with increased NaCl under both aerated and hypoxic conditions while K+ was depressed when salinity and hypoxia were applied together and Ca2+ was mostly decreased by NaCl. In general, hypoxia had greater effects on nutrient concentrations than NaCl by decreasing N, P, S, Mg, Mn, Zn, and Fe in shoots and by increasing B concentrations. The threshold salinity levels decreased markedly for germination, uptake of a range of nutrients, and for seedling growth of barley under hypoxic compared to well‐aerated conditions.  相似文献   

14.
氮钾水互作对玉米苗期植株生长及钾素吸收的影响   总被引:2,自引:0,他引:2  
采用盆栽试验方法探讨了氮钾水互作对玉米苗期植株生长及养分吸收的影响。结果表明,水分适宜能明显增加玉米植株株高和干物重,水分适宜条件下玉米株高和干物重较水分亏缺条件的分别增加7.8%和13.8%。增施氮肥能显著增加玉米植株株高和干物重,水分适宜条件下中氮水平的玉米株高和干物重分别较低氮水平的增加10.4%和8.7%,而水分亏缺条件下株高和干物重均随施氮水平的增加而明显增加;水分亏缺条件下,中高量施钾能显著增加玉米植株干物重。水分适宜条件下增施氮肥能明显促进玉米对钾素的吸收,在水分适宜和亏缺条件下,不同氮水平的玉米钾素吸收均随施钾水平的增加而显著增加。  相似文献   

15.
中国水稻不同产量、品种和种植制度下氮需求量变异状况   总被引:2,自引:0,他引:2  
Better understanding of the factors that influence crop nitrogen(N) requirement plays an important role in improving regional N recommendations for rice(Oryza sativa L.) production. We collected data from 1 280 plot-level measurements in different reaches of the Yangtze River, China to determine which factors contributed to variability in N requirement in rice. Yield, variety, and cropping system were significantly related to N requirement. The N requirement remained consistent at about 18.6 kg N Mg~(-1)grain as grain yield increased from 7 to 9 Mg ha~(-1), then decreased to 18.1, 16.9, and 15.9 kg N Mg~(-1)grain as yield increased to 9–10, 10–11, and 11 Mg ha~(-1), respectively. The decreased requirement for N with increasing yield was attributable to declining N concentrations in grain and straw and increased harvest index. Super rice variety had lower N requirement(17.7 kg N Mg~(-1)grain) than ordinary inbred and hybrid varieties(18.5 and 18.3 kg N Mg~(-1)grain, respectively), which was a result of lower grain and straw N concentrations of super rice. The N requirements were 19.2, 17.8, and 17.5 kg N Mg~(-1)grain for early, middle, and late rice cropping systems, respectively. In conclusion, the rice N requirement was affected by multiple factors, including yield, variety, and cropping system, all of which should be considered when planning for optimal N management.  相似文献   

16.
ABSTRACT

Plant breeders require a classification of the limitations and the capabilities that exist in plants by appropriate statistical methods; this issue leads to the concept of the ideotype. Therefore, the aim of this research was to determine the ideotype of improved rice cultivars. The experiment was carried out based on a randomized complete blocks design with three replications and 13 improved rice cultivars in northern Iran in 2016 and 2017, the required data for determining ideotype was collected. The results demonstrated that the optimal values of six important traits which selected by the multiple regression model explained 64% of the paddy yield (PY). The determined ideotype would increase PY from 6,623 kg ha?1 to 8764–9685 kg ha?1. Selection of desirable phenological traits revealed the highest correlation with the first canonical variable, can cause of selection of superior cultivars with the best agronomic traits. The most genetic distance was observed between cv. ‘Kados’, ‘Shiroodi’ and ‘Dasht’ using mahalanobis method. It was concluded that the methods used in this study, owing to its concern with the genetic variations between cultivars, can be used in determining plant ideotypes in conjunction with other methods and it can guide plant breeders to move through ideotype crops.  相似文献   

17.
Abstract

Concentration ratios (CR values) for cesium and strontium were measured in tumbleweed shoots as a function of plant age and radionuclide concentration in a totally mixed soil and radionuclide system. At a given plant age, CR values were found to be independent of soil concentration over five orders of magnitude for Sr and three orders of magnitude for Cs. CR values for Sr in 4‐, 8‐, and 12‐week old plants were 10.8, 9.6, and 19, and for Cs were 0.025, 0.033, and 0.053, respectively. Based on shoot growth and tissue concentration data for Sr and Cs, the CR values appear to be dependent on shoot dry matter production, with the rate of uptake of Sr and Cs remaining relatively constant over the 12‐week period.  相似文献   

18.
Rising carbon dioxide (CO2) concentration causes fertilization effects resulting in enhanced crop biomass and yields and thus likely enhances nutrient demand of plants. Hence, this field study was carried out to investigate the effects of elevated CO2 and N on biomass yield, nutrient partitioning, and uptake of major nutrients by soybean (Glycine max L.) using open‐top chambers (OTCs) of 4 m × 4 m size. Soybean was grown in OTCs under two CO2 [ambient and elevated (535 ± 36.9 mg L?1)] and four N levels during July to October 2016. The four N levels were N0, N50, N100, and N150 referring to 0, 50, 100, and 150% recommended dose of N. Both CO2 and N significantly affected biomass and grain yield, though the interaction was non‐significant. CO2 enrichment produced 30–65% higher biomass and 26–59% higher grain yield under various N levels. As compared to the optimum N application (N100), the CO2‐mediated increment in biomass yield decreased with either lower or higher N application, with the response being lowest at N150. As compared to ambient concentration, elevated CO2 resulted in significant reduction of seed P concentration at all N application levels but at N150, an opposite trend was observed. The decrease in seed P was maximum at N0 and N50 (7–9%) and by 3% at N100, whereas there was a gain of 7.5% at N150. The seed N and K concentrations were not affected either by CO2 or N application. Total N, P, and K uptake at harvest were significantly affected by CO2 and N, but not by CO2 × N interaction. Elevated CO2 resulted higher uptake of N by 18–61%, P by 23–62%, and K by 22–62% under various N treatments.  相似文献   

19.
Abstract

The influence of phosphate nutrition on the kinetics of phosphate absorption by sterile excised barley roots was examined. The roots of seedlings grown in dilute CaSO4 showed uptake kinetics similar to roots grown in phosphate deficient nutrient culture. The absence of microorganisms did not abolish the dual form of the absorption isotherm at pH 4.0

The most important effect of phosphate deficiency for uptake at low phosphate concentration was a marked decrease in the apparent dissociation constant of the ion‐carrier complex postulated to be involved in the uptake process. The results are discussed in relation to kinetic factors which may influence the efficiency of ion uptake by roots of different species of plants, including the apparent dissociation constant, the rate constant for uptake and the concentration of the ion‐carrier system.  相似文献   

20.
Soil and plant analysis has been a major contribution to the development of the agricultural sciences and indirectly to sustaining mankind. The advances that have occurred in the various disciplines in soil science, agronomy, and crop science would have been impossible without parallel advances in analytical technology. Despite the many divisions in the journals of the Soil Science Society of America, Crop Science Society of America, and American Society of Agronomy, none is solely devoted to the discipline of analysis of soils and plants and related areas. However, the Soil and Plant Analysis Council (SPAC) fills that critical void because it is an international society of scientists, educators, and private and public organizations with a common interest in promoting analysis of soils, plants, water, manure, and fertilizers. The primary emphasis is on nutrients in relation to crop production and increasing environmental issues. The main goal of SPAC is to provide leadership in the development and dissemination of methodology, interpretation, and application of analysis for efficient resource management and environmental protection. Its activities include publications (methods handbooks, symposia and workshop proceedings, newsletter), liaising with national agencies and commercial organizations to standardize and improve analytical procedures, maintenance of a laboratory directory, and holding international symposia. The Council has played a significant role in expanding the breadth, depth, and scope of analytical technologies in North America as well as internationally.  相似文献   

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