Leaching Potential of Diuron and Linuron in Gaza Soils

This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.

Linuron Biologically Effective Dose for Glyphosate-Resistant Giant Ragweed (<i>Ambrosia trifida</i>L.) Control in Soybean (<i>Glycine max</i>L.)

Glyphosate-resistant (GR) giant ragweed (Ambrosia trifida L.) was first identified in Canada in 2008 and has since been found throughout southwestern Ontario. Six field trials were conducted over a two-year period (2012, 2013) on Ontario farms with GR giant ragweed to evaluate the efficacy of linuron applied pre-plant (PP) in soybean (Glycine max (L.) Merr.). The dose required for 50%, 80%, and 95% GR giant ragweed control was 1238, 2959, and 6018 g·ai·ha-1 four weeks after application (WAA), respectively. The linuron dose needed for 50%, 80%, and 95% reduction in density was 1554, 3181, and 5643 g·ai·ha-1 and 1204, 2496, and 4452 g·ai·ha-1 for dry weight, respectively. Application of 7874 g·ai·ha-1 linuron was needed to obtain soybean yields that were 90% of the weed-free control;approximately 3.5 times the maximum field recommended dose. To achieve 95% and 98% yields, greater than 8640 g·ai·ha-1 linuron was required. Application of linuron plus glyphosate PP in soybean will help to control GR giant ragweed as well as reduce GR selection pressure.

利谷隆在玉米及土壤中的残留动态

采用高效液相色谱分析技术测定了利谷隆在玉米及土壤中的残留动态和最终残留量。喷施50%利谷隆可湿性粉剂(2812.5ga.i./hm2)测出在玉米植株上的残留量较低,施药后14d的残留量仅为0.08mg/kg;土壤中的原始沉积量为7.02mg/kg,半衰期为2.1d,据施药后第14d采样,消解率为72%。利谷隆属于易降解农药。

液相色谱-串联质谱法测定肉及肉制品中利谷隆及其代谢产物3,4-二氯苯胺残留

建立了液相色谱-串联质谱分析多种肉及肉制品中利谷隆及其代谢产物3,4-二氯苯胺残留的方法。样品用丙酮-乙腈(5∶95,v/v)提取,冷冻去脂,经弗罗里硅土固相萃取柱净化后进行液相色谱-串联质谱检测,采用内标法定量。利谷隆及3,4-二氯苯胺在1～500μg/L范围内呈良好的线性关系,相关系数(r)均大于0.998,方法的定量限(信噪比(S/N)>10)为10μg/kg,检出限(S/N>3)为5μg/kg。在各种肉及肉制品基质中添加低、中、高3种不同水平的利谷隆及3,4-二氯苯胺,其回收率范围分别为88.3%～101.2%和91.6%～101.6%,相对标准偏差(RSD)分别为4.8%～13.7%和4.7%～11.8%。结果表明所建立的方法可以满足肉及肉制品中利谷隆和3,4-二氯苯胺残留量的检测需要。

利谷隆在土壤中的吸附过程与机理

利谷隆是一种广泛应用的除草剂。本文研究了它在４种不同理化特性土壤中的吸附过程（平衡吸附所需的时间，土壤ｐＨ的影响及吸附等温线）和在单离子饱和的粘土矿物上的吸附机理。结果表明：利谷隆在土壤上的吸附强度大（Ｋｆ值在３．８８—９３．８４）；达到吸附平衡的时间短（５ｈ）；ｐＨ值降低，有利于吸附，ｐＨ在４—６范围内变化较明显．另外，利谷隆在土壤中形成氢键、配位键及离子键是可能的。

Control of volunteer adzuki bean in soybean

The objective of this research was to evaluate the efficacy of various pre-emergence (PRE) and post-emergence (POST) herbicides for the control of volunteer adzuki bean (Vigna angularis (Willd.) Ohwi & Ohashi) in soybean (Glycine max L.). Trials were conducted at two locations in 2005, 2006, 2007, and 2009. Experiments were arranged in a randomized complete block design with either five PRE or nine POST herbicides. Volunteer adzuki bean interference in soybean resulted in yield loss of up to 25%. Cloransulam-methyl, linuron, metribuzin, flumetsulam, and imazethapyr applied PRE provided up to 6, 24, 14, 8, and 0% control, respectively at 8 weeks after emergence (WAE), while acifluorfen, fomesafen, bentazon, thifensulfuron-methyl, cloransulam-methyl, imazethapyr, and imazethapyr plus bentazon applied POST provided 2, 2, 5, 34, 6, 4, and 12% control, respectively at 8 weeks after application (WAA). Generally, with the aforementioned herbicides, soybean yield was equivalent to the weedy control and soybean grain contamination with adzuki bean seed was consistently above the 1% maximum threshold. Chlorimuron-ethyl and glyphosate applied POST provided up to 84 and 94% visual control at 8 WAA, respectively, decreased adzuki bean density, biomass, and seed production, and generally decreased soybean contamination with adzuki bean below the 1% threshold. The only herbicides evaluated in this study that controlled volunteer adzuki bean in soybean were chlorimuron-ethyl (9 g ai.ha-1) and glyphosate (900 g ai.ha-1) applied POST. All the other PRE and POST herbicides evaluated did not provide adequate control of volunteer adzuki bean in soybean.

Control of glyphosate resistant giant ragweed in soybean with preplant herbicides

Giant ragweed was the first glyphosate resistant weed identified in Canada. It is a very competetive weed in row crop production and has been found to drastically reduce yields of soybean;therefore, control of this competitive weed is essential. The objective of this study was to determine effective control options for glyphosate resistant giant ragweed in soybean with herbicides applied preplant. Eighteen herbicide combinations were evaluated in field studies conducted in 2011 and 2012 at five locations with confirmed glyphosate resistant giant ragweed. Glyphosate plus 2,4-D ester or amitrole provided the best control of glyphosate resistant giant ragweed 4 WAA. Glyphosate plus 2,4-D ester provided 98 to 99% control and was equivalent to the weed free check at all locations. Glyphosate plus amitrole provided 90% to 93% control and was equivalent to the weed free check at 4 of 5 locations. Herbicides providing residual activity provided variable control across all locations. Of the herbicides with residual activity evaluated, glyphosate plus linuron provided the best control of glyphosate resistant giant ragweed;however, control was inconsistent across locations and years. Glyphosate plus linuron provided 23% to 99% controland was equal to the weed free check at one location 8 WAA.

利谷隆原药的高效液相色谱分析

采用反相高效液相色谱外标法对利谷隆原药中的有效成分进行定量测定，该方法的 平均回收率为 １００．０１％，变异系数为 ０．１７％。

玉米罐头中脲类除草剂的液相色谱法测定

采用基质固相分散-高效液相色谱法同时测定甜玉米粒罐头中利谷隆和氟酮磺隆两种脲类除草剂。考查了分离条件如分散剂种类、样品与分散剂质量比、洗脱剂pH值及洗脱体积的影响情况。色谱条件为:反相C18柱,流动相V(甲醇)∶V(水)=70∶30,pH=3.6,200nm紫外检测。氟酮磺隆、利谷隆平均回收率分别为87.80%和94.49%,相对标准偏差分别小于1.62%和1.08%,方法检出限分别为108ng/g和54ng/g。

3种除草剂对全膜双垄沟播玉米田杂草防治效果的研究

为了明确3种除草剂对全膜双垄沟播玉米田杂草的防治效果,采用随机区组法开展了田间小区药剂试验。结果表明：40%氰津·乙草胺悬浮剂3450 mL/hm^2防效好,玉米出苗后30 d和45 d的株防效分别为92.89%和90.99%,出苗后45 d鲜重防效为90.39%,对玉米安全,无药害发生,玉米产量为9826.5 kg/hm^2,较对照增产28.23%。50%利谷隆可湿性粉剂防效最好,但处理区有药害发生,减产率为50.72%-63.16%。

40%利·乙草胺可湿性粉剂防除玉米田杂草试验

在田间条件下,对40%利·乙草胺可湿性粉剂及乙草胺、利谷隆两单剂在玉米田的除草效果以及对玉米的安全性进行了试验研究。结果表明,40%利·乙草胺可湿性粉剂在2250～4500 g/hm2剂量下对玉米田单、双子叶杂草均有较好的防效,并且对玉米安全无害,对环境友好,具有广阔的推广前景。

纳米材料结合高效液相色谱法测定食品中利谷隆

针对食品中利谷隆萃取难、检测难的问题,提出磁性氧化石墨烯纳米复合材料结合高效液相色谱萃取和测定食品中利谷隆。通过对萃取条件和洗脱条件的优化,完善了利谷隆的萃取过程,然后对方法的分析性能进行表征。试验结果表明,萃取剂用量和种类为12 mg磁性氧化石墨烯纳米材料,萃取条件为25℃,溶液pH值为7,萃取时间为10 min,然后用3.5 ml的丙酮进行洗脱。通过对洗脱液进行检测验证方法准确性,该方法在0.006~0.12μg/ml的线性范围内,相关系数超过0.99,检出限与相对标准偏差分别为0.001μg/ml和1.9%,实际样品加标回收率为92.5%~105%,在信噪比(S/N)≥10的条件下,其定量限为0.006μg/ml,且不受其他农药离子的影响,表现出良好的综合性能。

25%利·辛悬浮剂防治玉米田杂草药效研究

采用田间试验方法，研究了喷施25％利·辛悬浮剂对玉米田单子叶和双子叶杂草的防除效果。结果表明：夏玉米3～5叶、杂草2～4叶期茎叶喷雾1次，对马唐、反枝苋、马齿苋和铁苋菜等杂草防效较好，推荐剂量1125～1500mL／hm^2。

水中利谷隆氯化降解动力学和消毒副产物生成特性

采用常用消毒剂次氯酸钠对含氮除草剂利谷隆开展了氯化降解实验研究,系统考察了加氯量、p H值、加Br-量以及温度对降解效果的影响,分析了氯化反应过程中消毒副产物生成特性.结果表明,次氯酸钠对利谷隆的氧化降解过程符合二级反应动力学;p H值对该降解反应影响较大,当p H值为7时反应速率最快,其中HOCl、OCl-与利谷隆的基元反应速率常数分别为4.84×102L·(mol·h)-1和3.80×102L·(mol·h)-1.在添加溴离子时,反应速率随着溴离子的加入逐渐减小.改变温度时,反应速率随着温度的增加而逐渐增大.利谷隆在氯化降解过程中可产生三氯甲烷、二氯乙腈、三氯硝基甲烷、卤代丙酮等多类型消毒副产物.在不同p H值和添加溴离子条件下,消毒副产物种类与浓度会出现显著差异.

多种光谱方法研究除草剂利谷隆与DNA的相互作用

在生理条件下(pH 7.4),采用紫外-可见光谱法、荧光光谱法、圆二色谱法(CD)和傅里叶红外光谱法(FT-IR)并结合粘度实验和熔点测量技术,研究了利谷隆与小牛胸腺DNA(DNA)的相互作用。实验发现,利谷隆可以置换出嵌入DNA中的亚甲基蓝,并使DNA的熔点和粘度升高,表明二者发生了嵌插作用。利谷隆的存在引起DNA的CD光谱收缩,表明DNA发生了B构象向C构象的转变;红外光谱分析表明嵌入DNA双链的利谷隆芳环主要作用于G、A碱基。

利谷隆及其代谢物在欧芹中的残留和膳食风险分析

[目的]初步了解我国国内欧芹产品中利谷隆及其代谢物的残留水平及膳食风险情况,为利谷隆的安全性评价提供科学依据。[方法]样品经乙腈提取,QuEChERS方法净化,用超高效液相色谱-串联质谱法对采购自全国的60份欧芹样品中利谷隆及其代谢物的残留进行检测,并通过风险商(RQ)对利谷隆膳食风险进行评估。[结果]60份欧芹样品中有19份为阳性样品,样品检出率为32%,残留值范围分别为<0.01~0.436 mg/kg。通过欧芹膳食摄入利谷隆的最高RQ为0.02。[结论]全国采购的欧芹中利谷隆的膳食暴露风险在可接受水平,不会对一般人群健康产生不可接受的风险。

利谷隆对穗状狐尾藻的毒性影响

[目的]通过科学评价利谷隆对穗状狐尾藻的毒性效应,为该农药的生态环境风险评估提供基础数据。[方法]试验采用半静态法,将穗状狐尾藻暴露14 d,观察其生长状态,确定利谷隆在水沉积物系统中对穗状狐尾藻营养生长的影响。[结果]利谷隆对穗状狐尾藻茎长、根长、整株长度、鲜重及干重的14 d平均比生长率抑制半效应浓度(14 d-ErC50)分别为0.278、0.331、0.225、0.390、0.318 mg/L,平均生物量增长量抑制半效应浓度(14 d-EyC50)分别为0.173、0.259、0.164、0.247、0.222 mg/L。[结论]利谷隆对穗状狐尾藻茎长、根长、整株长度、鲜重及干重的生长影响在低质量浓度(0.03 mg/L)时表现出刺激作用;高质量浓度(2.43 mg/L)时对茎长、根长、整株长度、鲜重及干重的抑制呈现良好的剂量-效应关系,即随着利谷隆溶液浓度增加,抑制作用呈上升趋势。