酒泉市棉花病虫害发生规律与气象条件的初步分析

利用敦煌、安西、金塔三地气象和病虫害资料,应用农业气象中的统计方法,分析了棉花病虫繁殖危害与气象条件的关系。结论是：影响棉花产量及品质的主要虫害是棉蚜、棉铃虫、棉红蜘蛛;影响虫害繁殖的主要气象因子是温度、湿度、降水等。可以通过采取生态措施和工程措施改善病虫害对棉花的威胁程度。     

应用Cotton2k模型模拟北疆棉花生长结果的分析

Cotton2k模拟模型是一个动态模型,能在生理过程水平上模拟棉花的生长发育和产量形成。通过应用棉花生产管理系统(GOSSYM/COMAY)中一种机理性很强的棉花生长模拟模型Cotton2k,对新疆北部地区棉花的生长状况进行模拟。从生育期的模拟结果分析得出除60%吐絮期误差较大外,其他生育期的模拟结果非常好;从形态发育模拟和实测结果比较表明:形态发育在花铃期前基本吻合;各器官干物质重的模拟和实测结果比较表明:除叶重误差较大外,其他的模拟结果较为满意,特别是植株干重的模拟可以作为精准农业水肥诊断的依据;植株中氮浓度的模拟误差较大,其原因分析有二:(1)棉花在生长发育过程中本身的生物学特性决定了每个生育期对不同肥的吸收量值不同,导致模拟值与观测值有差异;(2)在播种前应对试验地的肥力进行测定,使原始含N量的差异排除,会对模拟结果的精度有所提高。各层土壤含水量的模拟结果表明:耕作层0~45的土壤水分含量差异较大,但是45 cm以下土层的土壤含水量模拟结果与实测值基本吻合;不同水肥处理方式下的产量模拟结果和实测结果比较,产量模拟的误差较大。     

巯基棉分离富集－感耦等离子体发射光谱法测定河流湖泊底泥中总汞

利用巯基棉强选择性吸附的特点，将底泥中Ｈｇ与其共存元素有效地分离而富集，避免了大量Ｆｅ的干扰，实现了底泥中Ｈｇ的ＩＣＰ－ＡＥＳ摄谱法测定。对含Ｈｇ０．２２０μｇ／ｇ的标准参考物５次取样平行测定，其相对标准偏差（ＲＳＤ）为６．１％，按５～１０ｇ取样量，Ｈｇ的检测限为０．００１μｇ／ｇ，能满足水环境监测的需要。     

Hydrologic variability in black ash wetlands: Implications for vulnerability to emerald ash borer

Black ash (Fraxinus nigra) wetlands are widespread, forested landscape features in the western Great Lakes region. However, the future of these ecosystems is threatened due to impending spread of the invasive emerald ash borer (EAB), which results in tree mortality, decreased transpiration, and potential shifts to wetter, non-forested conditions. The vulnerability to such ecohydrologic shifts likely varies according to local hydrologic regimes controlled by landscape settings, but this site-dependent vulnerability and our ability to predict it is unknown. Here, we assessed vulnerability potential as a function of site hydrology in 15 undisturbed black ash wetlands from their three most common hydrogeomorphic settings in northern Minnesota: lowland, depression, and transition. Further, we used high-resolution (1-cm) surface elevation models to assess spatial variability of water levels at a subset of 10 sites. Although we observed similar ET and groundwater exchange rates among settings, lowland sites were generally drier because of elevated landscape position and greater water level drawdowns (via lower specific yield). We predict that such drier sites will exhibit greater water level increases following EAB-induced ash mortality, compared to wetter sites where open water evaporation and shallow-rooted understory transpiration will offset losses in tree transpiration. Moreover, compared to wetter sites, drier sites exhibited minimal microtopographic variation, limiting the number of elevated microsites for tree establishment and eventual canopy recovery after ash loss. These results suggest that site wetness is a simple and effective predictor of black ash wetland vulnerability to hydrologic regime change. To that end, we assessed the ability of common terrain metrics to predict site wetness, providing a potential tool to target vulnerable areas for active management efforts.     

Selenium Concentrations in Twenty-Six Geological Reference Materials: New Determinations and Proposed Values

The interest in selenium concentrations in whole rocks is growing, in part because it is a useful tool for base and precious metal exploration. Selenium is often neglected in whole rock geochemistry because of the inability of most laboratories to make reliable determinations of this element. A consequence of these difficulties is a paucity of assigned or certified values for Se in international geological reference materials, so that the "best practice" proposed by Kane and Potts (2007) to obtain robust values for such reference materials cannot be followed. In order to address this problem, we have determined Se by pre-concentration on thiol-cotton fibre followed by INAA (Se/TCF-INAA technique) in twenty-six international geological reference materials, and one quality control material (KPT-1). These values were used, in conjunction with a set of published values, to estimate Se concentrations for these twenty-seven reference samples. Robust statistics were developed for seven of the RMs, with standard deviations equal to or less than precisions calculated using the Horwitz function and so that consensus values could be proposed. For three of the RMs, the presence of outliers gave less robust results, and suggested values are proposed. For seventeen of the RMs, only information values are provided, because either insufficient determinations were available or because large standard deviations of the data were derived.     

银的野外快速分析方法——巯基棉富集-Ag-TMK-DBS三元络合物光导比色法

发展了一种能在野外测定0.25~1000μg/g银量的Ag-TMK-DBS三元络合物光导比色测定法。样品经硝酸封闭溶解后,用巯基棉富集分离银,在pH 4.5的乙酸-乙酸钠缓冲介质中,银与硫代米蚩酮(TMK)-十二烷基苯磺酸钠(DBS)形成易溶于水的红色三元胶束络合物,用自行开发研制的光导(比色)分光光度计比色测定痕量银。方法检出限为0.10μg/g,加标回收率为96.0%~99.4%,11次测定的精密度(RSD)小于5.76%。方法较为快速、简便、准确和灵敏,经国家一级标准物质验证,分析结果与标准值吻合。用光导分光光度计测定,准确度和精密度均有很大改进,结果与室内原子吸收光谱分析结果一致。方法具有广阔的应用前景。     

Fish community responses to invasive fish removal and installation of an exclusion barrier at Lake Ohinewai,Waikato

Introduced common carp (Cyprinus carpio) are a recognised threat to New Zealand’s freshwater ecosystems. In 2011, an invasive fish removal programme was undertaken in 16.8 ha Lake Ohinewai, a Waikato riverine lake. Active fish removal using netting and boat electrofishing was supported by installation of a one-way exclusion barrier on the outflow to Lake Ohinewai. The barrier was designed to allow fish passage downstream out of the lake, while preventing adult carp from moving upstream. The estimated carp population was reduced from 8,548 fish (5,863–12,937, 95% confidence limits) in 2011–454 fish (251–889, 95% CL) in 2014. However, by 2016 the carp population had recovered to 2,063 fish (1,070–4,328, 95% CL) with increased abundance in invasive brown bullhead catfish (Ameiurus nebulosus) also observed. This research demonstrates that carp populations can be reduced to low abundances in the short to medium term, but continued removal will be required for on-going control.     

近10a石河子热量变化对当地棉花生产的可能影响分析

利用石河子气象站1997—2006年气象资料,分别计算石河子近10a无霜期的长短以及10℃、15℃、20℃界限温度的初、终日期,持续时数,界限温度积温等热量指标。分析得出:近10a无霜期明显延长;10℃、15℃、20℃的界限温度的初日偏早,终日偏晚,持续日数大部分增加;活动积温显著增多。指出近10a是石河子热量最丰富的时期,并分析了近10a石河子热量变化对当地棉花生产的可能影响。为科学评估石河子气候资源、合理安排棉花生产提供科学参考。     

棉花产量要素预测模型

引起棉花产量波动的主要产量构成要素是株铃数和单铃重,作者将大田监测与气候统计相结合道德预测单株现蕾数,成铃雍铃重,对对最终产量进行预后,提高了产量预后准确率。     

基于电磁感应数据的膜下滴灌土壤水分动态变化研究

快速、无损监测农田土壤水分含量,是智慧农业的重要研究内容.以新疆南疆阿拉尔国家农业科技园区膜下滴灌棉田为研究对象,运用EM38-MK2大地电导率仪快速、高效的获取了4组不同时期的棉田土壤表观电导率数据,并同步采集表层土壤(0～20 cm)样品,通过构建表观电导率数据与室内测定含水量数据间的反演模型获取了测点的含水量数据...