黄河三角洲土壤(潮土)石油类含量对小麦的影响研究

本文在分析黄河三角洲土壤石油类含量状况、通过盆栽试验研究小麦对当地土壤 (潮土 )石油类含量耐受度的基础上 ,建立物流模型 ,得出了在不受污油、落地油污染的地方土壤 (潮土 )石油类含量对小麦的不利影响在较长时间内将是微弱的基本结论。     

Structure and function of rhizosphere and non-rhizosphere soil microbial community respond differently to elevated ozone in field-planted wheat

To assess the responses of the soil microbial community to chronic ozone(O_3), wheat seedlings(Triticum aestivum Linn.) were planted in the field and exposed to elevated O_3(e O_3)concentration. Three treatments were employed:(1) Control treatment(CK), AOT40 = 0;(2) O_3-1, AOT40 = 1.59 ppm·h;(3) O_3-2, AOT40 = 9.17 ppm·h. Soil samples were collected for the assessment of microbial biomass C, community-level physiological profiles(CLPPs), and phospholipid fatty acids(PLFAs). EO_3 concentration significantly reduced soil microbial carbon and changed microbial CLPPs in rhizosphere soil, but not in non-rhizosphere soil.The results of the PLFAs showed that e O_3 concentrations had significant effects on soil community structure in both rhizosphere and non-rhizosphere soils. The relative abundances of fungal and actinomycetous indicator PLFAs decreased in both rhizosphere and non-rhizosphere soils, while those of bacterial PLFAs increased. Thus the results proved that e O_3 concentration significantly changed the soil microbial community function and composition, which would influence the soil nutrient supply and carbon dynamics under O_3 exposure.     

The Evaluation of Mesoporous Materials as Catalyst in Fast Pyrolysis of Wheat Straw

In this study, wheat straw was chosen as a biomass sample and the fast pyrolysis of this sample was carried out with or without catalyst at different conditions in a well-swept fixed-bed reactor. Experiments were carried out in a well-swept tubular fixed-bed reactor with a heating rate of 300°C/min, between pyrolysis temperature ranges 300–800°C in the nitrogen atmosphere. The results indicated that a maximum oil yield of 31.9% was obtained at a pyrolysis temperature of 500°C in non-catalytic procedure. Siliceous and Al-MCM-41 materials were evaluated as potential catalysts in the pyrolysis experiments. Mesoporous materials have large pore dimensions with strong acid sites. These acidic sites catalyze some reactions in pyrolysis. The product yields and the quality of bio-oil were influenced with using MCM-41 materials. The bio-oil yield was reduced, whereas the gas yield increased with using a catalyst in the experiments. An increase in the fractions of pure phenol, alkyl phenols, alkenes+alkanes, carbonyls, aromatic, and cyclic compounds and a decrease in the fractions of methoxy phenols, acids+esters, furans, and alcohols were observed in the presence of Al-MCM-41 material. According to all results, the use of Al-MCM-41 materials as catalyst in the pyrolysis can be suggested to obtain both quality fuels and valuable chemicals.     

Transient‐phase and steady‐state kinetics of lipase‐catalyzed ester hydrolysis 1

Abstract

An experimental study has been made of both the steady‐state and the transient‐phase (presteady‐state) kinetics of the hydrolyses of several saturated aliphatic esters of p‐nitrophenol catalyzed by wheat germ lipase. The analysis of the presteady‐state part revealed two transients indicating that lipase‐catalyzed reactions proceed via a two‐intermediate mechanism suggested for other esterases. The possibility of more than one species of the enzyme engaged in catalytic activity is discussed and a reaction mechanism scheme is proposed accordingly.     

Removal of Pb(II) from wastewater using wheat bran

The adsorption of Pb(II) ions from aqueous solutions on wheat bran (WB) has been investigated as a function of initial concentration, adsorbent dose, adsorbent particle size, agitation speed, temperature, contact time and pH of solution. The equilibrium process was described well by the Langmuir isotherm model with maximum sorption capacities of 69.0, 80.7 and 87.0 mgg(-1) of Pb(II) on wheat bran at 20, 40 and 60 degrees C, respectively. Thermodynamic parameters, i.e. DeltaG(0), DeltaH(0) and DeltaS(0) have also been calculated for the system and the sorption process was found to be endothermic. Good correlation coefficients were obtained for the pseudo second-order kinetic model. The metal ion could be stripped by addition of 0.5M HCl, making the adsorbent regeneration and its reutilization possible.     

微波辐照麦秸制造活性炭

研究了微波辐照经氯化锌浸渍的麦秸制造活性炭。实验结果表明,经微波辐照８ｍｉｎ,所得到活性炭的亚甲蓝脱色力为１７０ｍＬ／ｇ,为国家标准一级品（ＬＹ２１６－７９）的１．４２倍,时间仅为传统方法的１／４５。     

某火力发电厂周围小麦受SO2污染调查

对某火力发电厂排放SO2导致其周围小麦受污染的突发性事故进行了调查。通过实地勘察小麦的受害症状，发现小麦呈典型的硫氧化物危害和硫酸雾腐蚀特征；小麦生物学性状和产量调查结果表明，污染区与对照区小麦无论株高、茎粗、穗长均无显著差异。而小麦的产量已受到影响，与对照区相比差异极显著；污染区小麦叶片全硫量和水溶性硫测定结果表明，全硫量均值为0．759％，高出对照区全硫含量均值0．651％的17％，经t检验差异显著；水溶性硫含量均值0．64％，高出对照区水溶性硫含量均值0．52％的23％，经检验差异极显著，表明污染区小麦受害确系SO2所致；分析气象条件认为污染区小麦是在低气压、高湿度、低风速、偏西风和稳定天气频率偏高的状况下受到污染的。     

Effect of Florasulam on soil residues and enzyme activity of wheat in drylands北大核心CSCD

Florasulam is a three azole and pyrimidine sulfonamide herbicide, mainly used for weeds prevention and control in winter wheat fields. The main purpose of this experiment was to study the effects of different doses of Florasulam on soil residues and on the enzymatic activity of wheat cultivated in drylands, and to provide the theoretical basis for a scientific use of florasulam. Five doses (0, 15, 30, 45, and 60 mL/667 m2) of Florasulam were applied in order to detect differences in soil residue content and enzymatic activities. Soil residues and enzymatic activities (catalase, phosphatase, urease, dehydrogenase) were measured and analyzed after the 5 different doses of Florasulam were processed. The residual amount of Florasulam in the soils decreased gradually with the growth phase of wheat, and was lower than that of 0.01 mg/kg. The residual amount of Florasulam in different soil layers gradually decreased with the increase of soil thickness. The enzymatic activity of soils treated with Florasulam was basically T3 > T2 > T1 > CK > T4, where T3 was the highest, whereas T4 could inhibit the enzymatic activity. Under these experimental conditions, in order to decrease soil pollution and lower Florasulam residues, it is recommended to apply Florasulam at a concentration range of 30 to 45 mL/667 m2 © 2018 Science Press. All rights reserved.     

重庆市巴县,长寿县水稻和小麦的重金属污染

重庆市巴县和长寿县的部分水稻和小麦已经受到重金属汞、镉、铅的污染，污染程度长寿县〉巴县，小麦〉水稻，铅〉汞〉镉。污染的主要原因是环境污染所造砀 ，尤其是重化工业所在场镇附近污染特别显著，汞和铅污染有加重趋势，镉污染有所减轻，提出了对策建议。     

Crop residue removal and fertilizer N: Effects on soil organic carbon in a long-term crop rotation experiment on a Udic Boroll

Biofuels can be produced by converting cellulose in crop residues to ethanol. This has recently been viewed as a potential supplement to non-renewable energy sources, especially in the Americas. A 50-yr field experiment was analyzed to determine the influence of (i) removing approximately 22% of the above-ground wheat (Triticum aestivum L.) residue each crop year, and (ii) N and P fertilization on soil carbon (C) in the top 15 cm depth of a fallow–wheat–wheat (F–W–W) rotation. The study was conducted from 1958 to 2007 on a clay soil, at Indian Head in sub-humid southeast Saskatchewan, Canada. Soil C concentrations and bulk densities were measured in the 0–7.5 and 7.5–15 cm depths in 1987, 1996 and 2007 and soil C changes were related to C inputs estimated from straw and root yields calculated from regressions relating these to grain yields. Two soil organic matter models [the Campbell model and the Introductory Carbon Balance Model (ICBM)] were also used to simulate and predict the effects of the treatments on soil C change over time, and to estimate likely soil C change if 50% or 95% of above-ground residues were harvested each crop year. Crop residue removal reduced cumulative C inputs from straw and roots over the 50-yr experiment by only 13%, and this did not significantly (P > 0.05) reduce soil C throughout the experiment duration. However, after 50 yr of applying N fertilizer at recommended rates, soil C increased significantly by about 3 Mg ha⁻¹ compared to the non-fertilized treatment. The simulated effect of removing 50% and 95% of the above-ground residues suggested that removing 50% of the straw would likely have a detectable effect on the soil C, while removing 95% of the straw certainly would. Measurements and model simulations suggest that adoption of no-tillage without proper fertilization will not increase soil C. Although it appears that a modest amount of residue may be safely removed from these Udic Borolls (Black Chernozems) without a measurable effect on soil C, this would only be feasible if accompanied by appropriate fertility management.