东北地区不同灌溉方式对玉米生长及其产量的影响

东北地区是我国玉米的主要产区,本文研究了自然降雨、膜下滴灌和喷灌三种不同灌溉方式对玉米生长的影响,结果表明膜下滴灌的玉米株高、茎粗、叶面积均优于喷灌和自然降雨,与自然降雨相比,膜下滴灌的最终株高比自然降雨高56％,喷灌和膜下滴灌可分别增加最终茎粗11％和42％;在玉米播种时期、出苗时期膜下滴灌土壤含水量要明显高于其他两...     

关于黑龙江省玉米膜下滴灌发展现状的调研

2011年4月12日至5月10日,我们与省水利科学研究院节水灌溉项目办组成玉米膜下滴灌联合调研组,深入我省西部玉米种植区的肇州县、肇源县、甘南县、龙江县等地,开展了玉米膜下滴灌发展现状调研。调研组通过与玉米膜下滴灌项目管理人员和种植农户座谈,向农户发放调查问卷,踏查膜下滴灌现场等方式,获取了大量翔实、可靠的资料,并结合2009-2010年玉米膜下滴灌试验示范成果,形成此报告。     

玉米膜下滴灌在大庆市的发展与推广

玉米膜下滴灌技术是覆膜种植与滴灌技术的相结合,初步实现了浇水、施肥一体化和可控化．由传统的大水漫灌,转向了浸润式灌溉。膜下滴灌与常规种植方法相比较,节水、节肥、省工、节地、增产、提质、增效。大庆市在气候特点和社会需要等方面很适合发展玉米膜下滴灌。该文在分析玉米膜下滴灌节水、增产机理的基础上,从大庆市的气候条件,现代农业需要和产生的效益等方面论述了大庆市发展玉米膜下滴灌的必要性。虽然其推广中仍存在一定的问题,但膜下滴灌的优势已经显现。     

赤峰市玉米膜下滴灌技术推广模式及投资分析

基于赤峰市玉米膜下滴灌工程试验、推广资料及其工程投资情况,以赤峰市常种作物玉米为研究对象,采用试验与数据分析的方法,分析了赤峰市玉米膜下滴灌节水、增产及其投入成本,总结赤峰市玉米膜下滴灌工程技术及栽培模式。结果表明,赤峰市玉米膜下滴灌工程通过分水调压和辅管轮灌,亩均投资降低114元,亩均节水110~140 m3、亩均增产230~260 kg,单方水粮食(玉米)生产能力由原来的2.9~4.1 kg/m3提高到10.33~13.9 kg/m3,可为同类地区推广玉米膜下滴灌工程提供借鉴。     

节水增产效益显著的玉米膜下滴灌技术

武威市的农作物以春小麦和玉米为主，约1/3的耕地种植着地膜玉米。2001～2003年对玉米膜下滴灌技术进行了连续3a的节水机理和需水规律试验研究，研究成果表明，玉米膜下滴灌技术具有增产12％以上。节水35％～50％的良好效畏。2005-2006年度，对玉米膜下滴灌技术进行了推广，推广情况表明，玉米膜下滴灌技术是一项成熟的实用技术，其效益主要体现在显著的节水效能方面，正确定位水资源的价值是评价玉米膜下滴灌技术效益的关键。     

DSSAT模型在玉米膜下滴灌模式下的应用研究

采用DSSAT作物分析模型来模拟玉米膜下滴灌的生长发育情况,确定吉林省中部玉米的6个常用DSSAT模型参数和DSSAT模型在吉林省玉米膜下滴灌模式下的应用方法。对比3种不同行距的均匀垄距与常规膜下滴灌的叶面积指数和产量等因素,得出65 cm垄距作为DSSAT模型中模拟膜下滴灌的垄距方案。对比常规均垄滴灌65 cm种植的玉米处理组和膜下滴灌均垄65 cm种植的玉米处理组,运用DSSAT模型与实测数据对比表明:方案1可视为最理想的模型参数方案。本研究成果为DSSAT在吉林中部玉米膜下滴灌种植模式下的应用提供支持。     

景电灌区玉米膜下滴灌耗水规律及产量效应

通过微型蒸渗器和土壤烘干称重法测定了不同滴灌定额条件下玉米耗水规律、农田灌溉水消耗、水分利用效率及经济效益,并结合气象数据分析滴灌技术较常规灌溉的优越性,分析了滴灌玉米耗水规律、棵间蒸发规律、产量及水分利用效率,以及膜下滴灌对玉米水分利用效率的影响。结果表明:在景电高扬程提水灌区,玉米采用膜下滴灌技术能有效减少作物生育期耗水量及棵间土壤蒸发量,提高农田水分利用效率,适宜的滴灌定额可减少玉米耗水量150 mm,水分利用效率提高34%,经济效益提高10.4%。在实际生产中可根据水源、基础设施条件适度开展膜下滴灌技术推广应用。     

基于回归分析的玉米膜下滴灌适宜土壤含水量及阈值研究

为确定半干旱地区膜下滴灌条件下玉米生长与土壤含水量间的关系,利用通榆灌溉试验站2018年度玉米膜下滴灌灌溉制度试验数据,分析不同灌溉制度下的玉米产量,并对不同灌溉制度下的玉米株高、茎粗、叶面积等指标进行回归求解,得到了玉米各生育阶段的适宜土壤含水量及其阈值.玉米膜下滴灌各生育阶段的适宜土壤含水量区间:苗期65％—75％...     

玉米膜下滴灌在大庆市的发展与推广

玉米膜下滴灌技术是覆膜种植与滴灌技术的相结合,初步实现了浇水、施肥一体化和可控化,由传统的大水漫灌,转向了浸润式灌溉.膜下滴灌与常规种植方法相比较,节水、节肥、省工、节地、增产、提质、增效.大庆市在气候特点和社会需要等方面很适合发展玉米膜下滴灌.该文在分析玉米膜下滴灌节水、增产机理的基础上,从大庆市的气候条件,现代农业...     

内蒙古东部黑土区覆膜玉米土壤水分及地温变化规律初步研究

文章研究了三种处理下(膜下滴灌、无膜滴灌、无膜不滴灌)不同土层土壤含水率的变化、土壤温度波动及对玉米生长的变化趋势。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。