共查询到20条相似文献，搜索用时 645 毫秒
1.
Lin CH Lerch RN Thurman EM Garrett HE George MF 《Journal of agricultural and food chemistry》2002,50(21):5816-5824
Balance (isoxaflutole, IXF) belongs to a new family of herbicides referred to as isoxazoles. IXF has a very short soil half-life (<24 h), degrading to a biologically active diketonitrile (DKN) metabolite that is more polar and considerably more stable. Further degradation of the DKN metabolite produces a nonbiologically active benzoic acid (BA) metabolite. Analytical methods using solid phase extraction followed by high-performance liquid chromatography-UV (HPLC-UV) or high-performance liquid chromatography-mass spectrometry (HPLC-MS) were developed for the analysis of IXF and its metabolites in distilled deionized water and ground water samples. To successfully detect and quantify the BA metabolite by HPLC-UV from ground water samples, a sequential elution scheme was necessary. Using HPLC-UV, the mean recoveries from sequential elution of the parent and its two metabolites from fortified ground water samples ranged from 68.6 to 101.4%. For HPLC-MS, solid phase extraction of ground water samples was performed using a polystyrene divinylbenzene polymer resin. The mean HPLC-MS recoveries of the three compounds from ground water samples spiked at 0.05-2 microg/L ranged from 100.9 to 110.3%. The limits of quantitation for HPLC-UV are approximately 150 ng/L for IXF, 100 ng/L for DKN, and 250 ng/L for BA. The limit of quantitation by HPLC-MS is 50 ng/L for each compound. The methods developed in this work can be applied to determine the transport and fate of Balance in the environment. 相似文献
2.
Lin CH Lerch RN Garrett HE George MF 《Journal of agricultural and food chemistry》2003,51(27):8011-8014
Chlorine has been widely employed for the disinfection of drinking water. Additionally, it has the capacity to oxidize many organic compounds in water. Isoxaflutole (Balance; IXF) belongs to a new class of isoxazole herbicides. Isoxaflutole has a very short soil half-life and rapidly degrades to a stable and phytotoxic metabolite, diketonitrile (DKN). Further degradation of DKN produces a nonbiologically active benzoic acid (BA) metabolite. In experiments using high-performance liquid chromatography-UV spectroscopy (HPLC-UV) and HPLC tandem mass spectrometry (HPLC-MS/MS), DKN was found to rapidly react with hypochlorite in tap water, yielding the BA metabolite as the major end product. One milligram per liter (19 microM) of hypochlorite residue in tap water was able to completely oxidize up to 1600 microg/L (4.45 micromol/L) of DKN. In tap water, the disappearance of IXF was much more rapid than in DI water. As soon as the IXF is hydrolyzed to DKN, the DKN quickly reacts with the OCl(-) to form nonphytotoxic BA. As a result, the herbicide solutions prepared with tap water at 500 microg/L will no longer possess any herbicidal activity after 48 h of storage. However, in agronomic settings, highly concentrated tank solutions (600-800 mg/L) may be prepared with tap water since the conversion of IXF to BA would represent <5% of the herbicide; therefore, any impact on the herbicide efficacy would be negligible. Results of this study show that current chlorination disinfection protocols in municipal water systems would completely eliminate the phytotoxic form of this new herbicide, DKN, from drinking water supplies; yet, farmers can use chlorinated tap water without significant loss of efficacy. 相似文献
3.
The transformation of isoxaflutole (ISOX) to its herbicidally active diketonitrile degradate (DKN) was significantly enhanced in the presence of soil and occurred more rapidly in systems containing soil with a greater soil pH. Sorption-desorption of ISOX and DKN in five soils collected within a field revealed both ISOX and DKN were more readily sorbed to soils with greater organic matter, clay content, and lower soil pH. Sorption of ISOX residues occurred within 2 h, and extracts contained similar concentrations of ISOX and DKN at 24 h, suggesting the 24-h sorption coefficients for ISOX-treated systems were actually for mixed ISOX residues. Freundlich sorption coefficients were 3 and 4 times greater for ISOX than for DKN. On the basis of the Freundlich organic carbon sorption constants, ISOX and DKN can be categorized in the very high and high mobility classes, suggesting their potential to leach in the soils needs to be evaluated. 相似文献
4.
Papiernik SK Yates SR Koskinen WC Barber B 《Journal of agricultural and food chemistry》2007,55(21):8630-8639
Two-year field dissipation studies were conducted in three soil types in Minnesota to examine the processes affecting the dissipation of the herbicide isoxaflutole and its phytotoxic diketonitrile metabolite (DKN) under relatively cool, wet soil conditions. Plots of cuphea were treated with isoxaflutole and potassium bromide, a nonsorbed, nondegraded tracer. Replicate soil cores were collected six times during the growing season to a depth of 1 m, and the bromide or herbicide concentration was measured in each of five depth increments. The dissipation half-life (DT50) of isoxaflutole + DKN was 8-18 days in each soil. Bromide and herbicide concentrations were low at depths >40 cm throughout the study, and herbicide concentrations in soil 100 days after application were usually undetectable. Simulation modeling using Hydrus-1D for the loam soil suggested that plant uptake was an important mechanism of dissipation. 相似文献
5.
Isoxaflutole (IXF; Balance) belongs to a new class of isoxazole herbicides. Isoxaflutole has a very short half-life in soil and rapidly degrades to a stable and phytotoxic degradate, diketonitrile (DKN). DKN was previously discovered to rapidly react with hypochlorite (OCl-) in tap water, yielding the benzoic acid (BA) degradate as a major product, but the complete reaction pathway and mechanism have not been elucidated. Thus, the objectives of this work were to (1) determine the stoichiometry of the reaction between DKN and OCl-; (2) identify products in addition to BA; and (3) propose a complete pathway and reaction mechanism for oxidation of DKN by OCl-. Stoichiometry of the reaction showed a molar ratio of OCl-/DKN of 2. In addition, two previously uncharacterized chlorinated intermediates were identified under conditions in which OCl- was the limiting reactant. The proposed chemical structure of a chlorinated benzoyl intermediate was inferred from a series of HPLC/MS and HPLC/MS/MS experiments and the use of mass spectral simulation software. A chlorinated ketone intermediate was also identified using ion trap GC/MS. Two additional end products were also identified: cyclopropanecarboxylic acid (CPCA) and dichloroacetonitrile (DCAN). On the basis of the reaction stoichiometry, the structure of the chlorinated intermediates, and the identification of the products, two reaction pathways are proposed. Both pathways involve a two-step nucleophilic attack and oxidation of the diketone structure of DKN, leading to formation of BA, DCAN, and CPCA. 相似文献
6.
巴基斯坦白沙瓦市铅和镉在不同路旁土壤及植物中的污染 总被引：1，自引：0，他引：1
Soil and plant samples were collected from roadside sites (along with primary, secondary and tertiary roads) and reference site to investigate the contamination of soils and old common plant species with lead (Pb) and cadmium (Cd) in Peshawar City, Pakistan. All the data were analyzed using ANOVA analysis that showed a significant (P ≤ 0.01) variation in Pb and Cd concentrations in the roadside soils and plants as compared to the reference site. The mean concentrations of Pb and Cd were 53.9 and 6.0 mg kg-1 in soils and 49.1 and 10.9 mg kg-1 in plants, respectively. Significant variation (P ≤ 0.01) in concentrations of Pb and Cd in soil and plant samples along with primary, secondary and tertiary roads might be due to different traffic densities. The highest value (9.4) of metal accumulation index (MAI) was observed for Eucalyptus camaldulensis. In selected plant species, the Pb and Cd accumulation was found in the order of E. camaldulensis > Ficus elastica > Dalbergia sissoo > Alstonia scholaris. The roadside soils and plants were highly contaminated with Pb and Cd as compared to the reference site. 相似文献
7.
Fate of isoxaflutole in soil under controlled conditions 总被引：1，自引：0，他引：1
Isoxaflutole (IFT, 5-cyclopropyl-1,2-oxazol-4yl-alpha,alpha,alpha-trifluoro-2-mesyl-p-tolyl ketone) is a new pre-emergence proherbicide used in maize and sugarcane. Its two main derivatives are a diketonitrile derivative, 2-cyano-3-cyclopropyl-1-(2-methanesulfonyl-4-trifluoromethylphenyl)propane-1,3-dione, called DKN, and a benzoic acid derivative, 2-methanesulfonyl-4-trifluoromethylbenzoic acid, called BA. Few data are available of the factors influencing the degradation of IFT in soil, and the purpose of the present work was to determine the relative importance of, and factors affecting, the degradation of IFT in soil. Experiments were conducted on five soils with distinct physicochemical characteristics, at different temperatures and moisture contents in biotic and abiotic conditions. The isomerization of IFT to DKN is rapid, increasing with higher moisture contents and higher temperatures. It depends strongly on pH and is governed by chemical processes. The degradation of DKN to BA appeared to be essentially due to the biological activity of the soil. 相似文献
8.
Waliszewski SM Carvajal O Infanzon RM Trujillo P Aguirre AA Maxwell M 《Journal of agricultural and food chemistry》2004,52(23):7045-7050
The organochlorine pesticides are lipophilic and persistent and tend to accumulate in soils and growing plants. The contamination of growing plants occurs by adhesion of volatile substances from the air to the plant surface and by the migration of contaminants through xylem in inner ascendant transport. Persistent organochlorine pesticides (HCB, alpha,gamma-HCH, pp'DDE, op'DDT, pp'DDT) levels were determined in soils and rye plants. The aims of the study were the monitoring of organochlorine pesticide concentrations and the comparison of these levels among soil, rye straw, and rye grains. Fifty soil samples and 50 rye plant (50 straw and 50 grains) samples were taken. The GLC-ECD chromatographic results indicated the following contamination levels distributed among soil, straw, and grains: HCB (0.7-1.2-0.7 microg.kg(-1)), alpha-HCH (0.6-3.4-1.2 microg.kg(-1)), gamma-HCH (1.8-27.3-4.4 microg.kg(-1)), Sigma-HCH (2.5-30.7-5.6 microg.kg(-1)), pp'DDE (1.0-7.8-5.5 microg.kg(-1)), op'DDT (16.1-20.4-17.0 microg.kg(-1)), pp'DDT (38.0-41.7-49.6 microg.kg(-1)), and Sigma-DDT (54.2-63.2-72.1 microg.kg(-1)). The study verified the presence of organochlorine pesticides in the Mexican agricultural environment and their migration from soil to the growing rye plants. However, DDT has been banned since 1999 for sanitary reasons, and Lindane is applied only in some cases as a seed dresser. The determined organochlorine pesticide levels in rye plants are low, at residual levels that are below Codex Alimentarius Commission maximum residue limits. 相似文献
9.
在桂林地区蔬菜和菜地土壤铜含量进行大规模调查基础上,评价其污染程度,并用THQ评估经食用蔬菜摄入铜的健康风险。结果显示,桂林地区菜地土壤铜含量范围、中值、算术均值和几何均值分别为11.69～348.8mg·kg-1和27.41、34.62、29.43mg·kg-1,与桂林市土壤背景值相比,桂林市菜地土壤铜没有明显的积累;桂林地区蔬菜铜含量范围和平均值分别为0.032～3.530mg·kg-1和0.324mg·kg-1,与其他城市蔬菜铜含量相比,桂林地区蔬菜铜含量处于较低水平,通过蔬菜摄入铜的健康风险小。蔬菜对铜的富集能力以辣椒最高,因而其抗污染能力较差,白菜、包菜和萝卜对铜的富集能力最低。 相似文献
10.
Beltran E Fenet H Cooper JF Coste CM 《Journal of agricultural and food chemistry》2000,48(9):4399-4403
A kinetic study of the chemical hydrolysis of isoxaflutole [5-cyclopropyl-4-(2-methanesulfonyl-4-trifluoromethylbenzoyl)is oxazol e (IFT)], a new herbicide recently developed by Rh?ne-Poulenc Agro, in buffered, sterile aqueous solutions was carried out in the dark at 295, 308, and 323 K and at nine pH values between 1.8 and 10.1. Samples were analyzed by HPLC-UV. The decrease in IFT concentration was accompanied by an increase in the concentration of its diketonitrile derivative (DKN). Obeying pseudo-first-order kinetics, isoxaflutole hydrolysis increased with increasing pH and temperature: for 295 K and pH 9.3 the rate of degradation was 100-fold faster than at pH 3.8. Using the Arrhenius equation, the rate constants K(obsd), activation energies E(a), and entropies DeltaS() were calculated, and plotting log(K(obsd)) against pH showed that the effect of pH varied with temperature. According to DeltaS() values the mechanism of the reaction was found to be different with respect to pH range. The benzoic acid derivative, known as a degradation product of DKN in plants, was not detected in the present study. 相似文献
11.
调查研究了伊犁州土壤中硒资源的分布特征,为该地区富硒农产品的开发提供理论指导。用原子荧光光度法测定了新疆伊犁州6个县158个农田土壤样品的全硒含量,并运用统计分析方法对伊犁州土壤硒资源的分布特征及与土壤理化性质的关系进行了分析。结果表明,伊犁州6个县土壤中全硒含量范围为0.14~2.75 mg·kg-1,几何均值为0.33 mg·kg-1,其中昭苏县土壤全硒含量均值最高,巩留县最低。所检测的土壤样品中有2.38%属于少硒土壤,78.57%属于足硒土壤(0.175~0.45 mg·kg-1),19.05%属于高硒土壤(0.45~3.00 mg·kg-1)。统计分析的结果表明,有机质、速效钾、碱解氮与全硒含量呈极显著正相关(P0.01),p H值与硒含量成显著负相关(P0.01)。伊犁州土壤中硒的含量水平偏高,可以优先考虑富硒农业的开发建设。 相似文献
12.
东北黑土有机碳的分布及其损失量研究 总被引：11，自引：0，他引：11
为了分析东北黑土土壤有机碳(SOC)的分布特征及其开垦以来黑土SOC的损失程度,我们于2004～2005年在黑龙江和吉林两省采集了32个自然黑土剖面样品,在每个自然黑土样品附近对应采集32个景观条件相似的耕作黑土样品。结果表明,自然黑土样品0～30cm土层SOC含量平均为32.20 g kg-1,最高可达63.46 g kg-1,黑龙江省自然黑土SOC含量(34.55 g kg-1)高于吉林省(23.80 g kg-1)。耕作土壤SOC平均含量为22.71 g kg-1,远低于自然土壤。受温度的影响,随着纬度的增加,自然黑土与耕作黑土SOC含量逐渐递增。由于土壤侵蚀以及耕垦和去除作物残留物等农业管理措施的综合作用,使得耕作黑土表层SOC含量小于自然黑土。与自然黑土相比,耕作黑土0～10cm土层SOC损失量在26.84%～46.57%之间,亚表层损失相对较少。黑土SOC含量下降也是土壤水土流失致使黑土层变薄的一个直接表现。耕作黑土表层流失厚度可以通过自然与耕作黑土剖面SOC含量的分异差值来估算。通过对土壤剖面上SOC的分布进行校正剔除土壤侵蚀的影响后得到的同等深度SOC含量的差值才可视为由耕作以及有机质输入量差异等因素造成的SOC损失量。未经校正而进行的自然黑土和耕作黑土同一深度SOC含量的比较可能过高估计了农业管理措施对土壤SOC损失量的影响。 相似文献
13.
Jasmina Vejnovic Branko Djuric Peder Lombnæs Bal Ram Singh 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(3):243-254
Deficient trace elements concentration in soils, forages, and animals have been reported in several areas of Balkan region. Main challenge in overcoming low productivity of forage and animal production in this region is the lack of data on the nutritional status of the pastures and soils. This study examined the nutrient and pseudo total concentration of trace elements in soil and herbage plants, and the potential deficiency or excess with regards to crop and livestock production. Soil and plant samples from 100 sampling points were collected in the mountainous grasslands of Manja?a (between longitudes 16°56′ and 17°8′ east; and latitudes 44°33′ and 44°42′ north) and Vla?i? (between longitudes 17°14′ and 17°29′ east; and latitudes 44°25′ and 44°37′ north). Soil samples were analysed for soil texture, pseudo total concentration (5?ml HNO3) of trace elements (TE), pH, soil organic carbon (SOC), while plant samples were analysed for TE. The soil pH varied from strongly acidic to moderately alkaline. The concentration of SOC varied from 0.5% to 12.3%. Most of the soil samples were finer-textured soils high in silt content. The average concentrations of Na, P, Zn, Se, Cu, Co, and B were low in both soil and herbage plants. Plant K, Ca, Mg, Mo, and Mn concentrations were sufficiently high to meet the requirements of grazing animals, while Fe concentrations was elevated in certain areas. High levels of Mo were found in both soil and plants. The results suggest that imbalances observed in natural pastures of Manja?a and Vla?i? area, caused by low soil TE concentration and other soil and plant properties, could contribute to poor animal nutrition. 相似文献
14.
《Communications in Soil Science and Plant Analysis》2012,43(15):2032-2045
This study was carried out to investigate the levels of copper (Cu) contamination in coffee fields in Kilimanjaro and Arusha regions, Tanzania, to increase the database on the contamination of soils by Cu-based fungicides in coffee fields. Surface (0–20 cm deep) soil samples were collected from different farms in Kilimanjaro and Arusha regions. Coffee, banana, and bean plant samples were collected from the locations of soil sampling. Soil and plant samples were analyzed at the Department of Soil Science, Sokoine University of Agriculture, Morogoro, Tanzania. It was found that the calcium chloride (CaCl2)–extractable Cu was less than the detection limit of flame atomic absorption spectrometry. Diethylenetriaminepentaacetic acid (DTPA)–extractable (24 to 366 mg Cu kg?1 soil) and aqua regia–extractable (80 to 806 mg Cu kg?1 soil) Cu levels were high enough to raise environmental alarm (based on European Union guidelines) in the Cu fungicide–treated soils as compared with natural Cu levels in untreated soils (1 to 12 mg Cu kg?1 soil for DTPA and 22 to 32 mg Cu kg?1 soil for aqua regia–extractable Cu). Coffee, banana, and bean plants grown on soils contaminated by Cu fungicides had varied concentrations of Cu that were greater than the concentrations of Cu in the plants collected from the uncontaminated soils. Stepwise regression analysis carried out to investigate the relationships between the soil properties and the concentrations of Cu in plants revealed a significant (P = 0.01) positive relationship (R2 = 0.4) between organic carbon and the concentration of Cu in banana leaves. Aqua regia–extractable Cu was positively correlated (P = 0.03, R2 = 0.4) with the concentrations of Cu in banana leaves. For bean leaves, electrical conductivity (EC) had a positive significant (P = 0.01) relationship (R2 = 0.56) with the concentrations of Cu in the plants. It is recommended that further research be carried out to investigate the dynamics and bioavailability of Cu for the different crops interplanted in the coffee fields. 相似文献
15.
通过实地调查,研究了江苏省22个典型茶园表层土样和12个剖面土样的全硒含量,分析了土壤全硒含量分布特性、有效硒含量及其影响因素。结果表明,江苏省典型茶园土壤全硒含量在0.10～1.78mg·kg-1之间,平均为0.50mg·kg-1,高于全国平均值。其中,宜兴地区土壤全硒平均含量为0.88mg·kg-1,明显高于其他地区的0.25mg·kg-1,但前者土壤硒活化率仅为4.94%,明显低于江苏省平均值9.04%。宜兴地区虽然土壤供硒潜力巨大,但要充分利用富硒土壤开发、生产富硒茶必须提高土壤中硒的活化率和可利用度。土壤有效硒与土壤pH值、CEC呈极显著正相关,在实际生产中可通过提高土壤pH值等改善土壤环境条件的方法来提高土壤硒的有效性,从而提高茶叶中硒的含量。研究区内硒在表层土壤中的相对含量趋向增加,生物积累大于淋溶作用。 相似文献
16.
南宁市土壤硒分布特征及其影响因素探讨 总被引：18，自引：0，他引：18
以南宁市土壤为对象,系统采集了2 767个表层土壤(0～20 cm)和711个母质样(150～200 cm)。用AFS原子荧光光谱法进行了样品全硒含量质量分数分析;研究了南宁市土壤全硒含量的分布特征及其与成土母质、土壤类型和土壤理化性质的关系。结果表明,南宁市土壤全硒含量变幅为0.09～1.34 mg kg-1,算术平均值为0.57 mg kg-1。土壤类型中,新积土全硒含量最高,平均为0.89 mg kg-1;紫色土全硒含量最低,平均为0.37 mg kg-1。成土母质中,全硒含量以二叠系碳酸盐岩母质发育土壤为最高,平均为0.79 mg kg-1;以下白垩系紫红色碎屑岩母质发育土壤为最低,平均为0.39 mg kg-1。影响南宁市土壤硒含量的主要因素是成土母质,土壤pH、有机碳及铁和铝的含量对土壤全硒含量的富集与分布也有一定影响。 相似文献
17.
硫是作物生长发育所需的营养元素。根据多年多点田间试验和土壤有效硫测定,研究福建主要粮经作物的硫肥效应、土壤有效硫临界指标和耕地土壤硫肥力状况。64个田间试验表明,福建主要农作物施用硫肥平均增产10.5%,增产幅度是旱作物>水稻>香蕉;水田土壤和旱地土壤有效硫临界指标分别为23mgkg-1和25mgkg-1。根据全省372个耕层土样有效硫测定结果,土壤有效硫含量平均为27.6mgkg-1,低于土壤有效硫临界值的样品数占57.0%,其中,闽东南地区耕地土壤有效硫缺乏程度比闽西北地区高;在土地不同利用类型中,旱地土壤有效硫总体比水田匮乏,旱地土壤有效硫平均含量是茶果园>菜园>农地,其中,农地土壤有效硫低于临界指标的样品占75.3%;水田中不同土种的土壤有效硫含量以埭田最高,灰沙泥田为最低,旱地则以灰赤土最高而风沙土最低。 相似文献
18.
表面活性剂LAS对土壤Cd形态及Cd在黄豆植株中分配的影响 总被引：1，自引：0，他引：1
A pot experiment was conducted to study the effect of an anionic surfactant linear alkylbenzene sulfonate （LAS） application on cadmium （Cd） fractions in soils and Cd distribution in different tissues of soybean （Glycine max） plants as well as soil pH. Soil samples were treated with three levels of Cd （0, 5, and 10 mg kg^-1） and five levels of LAS （0, 5, 15, 50, and 100 mg L^-1）. Results indicated that compared to the control soils （no Cd and no LAS treatment）, soil pH increased and available Cd decreased in the soil treated with external Cd and watered with LAS solutions. Meanwhile, soil exchangeable Cd and Cd bound to carbonates decreased; Cd bound to amorphous iron and manganese oxides and Cd bound to organic matter increased. In addition, LAS application could reduce enrichment of Cd in soybean plants, resulting in decreased Cd in the soybean plants. Thus, suitable LAS application could decrease bioavailability and mobility of soil Cd. 相似文献
19.
为了探讨0.01mol L-1 CaCl2和0.02mol L-1 SrCl2提取土壤氮、钾能力的差异,用0.01mol L-1 CaCl2和0.02mol L-1 SrCl2提取14个土壤样品,再分别用流动分析和火焰光度法测定提取液中的硝态氮和亚硝态氮之和和钾的含量,以1mol L-1 KCl和1mol L-1中性醋酸铵提取液作为无机氮和钾的对照提取剂,同时选择部分土壤样品用盆栽试验测定提取数量与土壤氮、钾有效性的关系。结果表明,两种方法和对照方法提取氮和钾数量的相关性均达到p<0.01水平,对照提取剂、0.01mol L-1 CaCl2和0.02mol L-1 SrCl2对于14个土壤的硝态氮和亚硝态氮之和提取含量平均值分别为13.36、15.33和26.62mgkg-1,14个土样的提取钾含量的平均值分别为120.4、33.58和54.24mgkg-1。盆栽试验结果表明,对照提取剂和0.01molL-1CaCl2和0.02molL-1SrCl2提取氮的数量与植物吸氮量的相关性达到p<0.05显著水平,钾的相关性达到p<0.01显著水平。与对照提取剂的氮、钾分别提取相比,SrCl2和CaCl2提取剂均可大大降低样品提取中试剂费用。以上结果表明,0.01mol L-1 CaCl2和0.02mol L-1 SrCl2提取对土壤氮和钾的提取能力均可反映土壤硝态氮和亚硝态氮、有效钾的含量和供应能力,而提取能力以0.02mol L-1 SrCl2为高。 相似文献
20.
选取华南地区广泛种植的杂交水稻品种“培杂泰丰”,利用外源添加砷（50 mg·kg-1）的土壤盆栽试验,研究不同施用量的磷硅肥对水稻生长特性和砷积累的影响。结果表明,施用磷硅肥的处理,水稻糙米中砷含量为0.504~0.586 mg·kg-1,低于农业部颁布的粮食中砷限量标准（NY 861—2004）中大米砷限值。相关性分析表明,水稻糙米砷含量与水稻植株的生物量、稻谷千粒重和秸秆中硅/砷摩尔比呈显著负相关,与秸秆中磷/砷摩尔比呈极显著负相关;糙米的砷含量随磷、硅肥的施加而降低。综合分析表明,在华南地区同类中度砷污染土壤中可有效控制砷向水稻籽粒运输累积的磷、硅肥最优施加量及配比为40 mg P·kg-1土、50 mg Si·kg-1土。 相似文献