有垂向入渗时土壤的洗滤脱盐

垂向入渗条件下土壤的洗滤淡化脱盐问题,是水利土壤改良生产实践中经常碰到的问题。本文着重对渠道排水、垂向渗滤的土壤脱盐为典型,研究了浓度时、空分布的准确表达式,并以此求算洗滤地块中的盐分浓度的分布和变化,其结果对实际有一定参考价值。     

三江平原典型垦区的治涝措施

三江平原为国家商品粮基地，洪涝灾害严重地影响该地区农业生产，红兴隆垦区地处三江平原腹地、土地低湿、微地形复杂，由于水利基础设施薄弱，洪涝灾害繁频发生。以红兴隆垦区为典型，阐述该垦区治涝原则及标准，以及分区的治涝对策。     

干旱区灌区水盐综合调控研究

土壤盐渍化是影响干旱区灌区农业发展的重要因素之一,且地下水过度开采阻碍土壤的脱盐作用,严重危害作物生长甚至导致出现弃耕现象,威胁国家粮食安全。在分析干旱区开都河流域典型灌区水盐特征的基础上,采用基于层次分析法的BP神经网络对不同水盐调控模式进行综合评价。结果表明,增加灌区作物滴灌比例、限制地下水开采量、实行冬灌措施既可以减少地表用水量,保证河流下游生态健康,维持地下水位的年际稳定更可以促进土壤的脱盐作用,降低土壤矿化度,减缓土壤盐渍化进程。研究结果探索出了以"地表-地下水资源统筹配置-土壤盐分控制-灌溉节水"三元一体的土地资源保护、灌溉模式改进和流域水资源开发的综合调控模式,可为干旱区灌区土壤盐渍化防治提供一定的参考依据。     

膜下滴灌土壤盐分特性及影响因素的初步研究

针对新疆盐碱地的改良特征，通过室内膜下滴灌土壤盐分运移试验，初步研究了土壤脱盐过程，滴头流量、灌水量等对脱直听影响。结果表明：膜下滴灌土壤盐分分布可划为达标脱盐区、未达标脱盐区及积直3个区域；土壤含盐量分布具有水平脱盐距离大于垂直脱盐距离的特点，滴头流量、土壤初始不量以及土壤初始含盐量的增加不利于达标脱盐区的形成；灌水量的增加有助于土壤脱盐。这些结果对膜下滴灌新技术开发利用盐碱地的生产实践有指标意义。     

微成水入渗土壤水盐运移特征分析

提高水分的淋洗脱盐效率也是节水的一个重要途径。通过室内垂直入渗试验研究了淋洗水量、入渗水质和土壤初始含水量对土壤脱盐状况和水分洗盐效果的影响。结果表明，脱盐深度随入渗水量的增加呈幂函数增加。随入渗水矿化度和土壤初始含水量的增加而减小；脱盐区土壤平均含盐量随累积入渗量的增加而减少，随入渗水矿化度和土壤初始含水量的增加而增加。水分的脱盐效率随淋洗水量的增加呈幂函数减小，随入渗水矿化度的增加线性减少。土壤初始含水量对初期水分脱盐效率有影响，但对后期水分脱盐效率影响不大。对脱盐效率影响因素的分析可以为设计合理的淋洗水量提供参考。     

垦翻找农机 农机倾全力

垦翻找农机农机倾全力莆田县农机局方向阳要垦荒找农机局！为贯彻落实省委、省政府关于冬季农业生产紧急电话会议精神，搞好冬季农业综合开发，加快垦区开发步伐，莆田县委、县政府决定发挥农机优势，由县农业机械局负责实施后海３０３垦区综合开发先期工程─－垦区冬翻拓...     

围绕农业结构调整大力调整农机装备结构

近年来，黑龙江垦区始终坚持把大力调整农业结构、实施农业产业化，作为垦区农业乃至整个经济发展的重要战略性措施。农业结构的调整离不开农业机械化的技术支撑，垦区农机化的发展，也始终坚持了围绕农业结构调整，大力调整农机装备结构，取得了可喜成就。     

朝邑内滩盐碱土成因及其改良利用

在改良利用盐碱土的各种综合措施中，设法降低并控制潜水位在临界深度以下，使土壤水分常年处于下渗为主的状态，有利于降水和灌溉对土壤淋洗脱盐，是消除土壤返盐和治理盐碱土的根本措施。     

大同县盐碱地综合改造技术

耕地在逐年减少,要保障粮食安全,最有效的途径之一是不断设法增加耕地,大同县大量的盐渍化土壤就是潜在的资源。近20年来,由于地下水位下降,自然脱盐明显,给大同县盐渍化土壤改良创造了有利条件。通过工程措施、化学改良、农业生物措施相结合,改造了盐渍化土壤,总结出盐碱地综合改造技术。     

实施节水灌溉战略发展垦区农业经济

为了研究发展垦区农业经济的政策，措施、从分析垦区农业发展面临的严峻形势入手，并考虑水资源状况，研究了全方位抓好小型喷灌机的应用推广工作的方法，并进而从资金筹措、产制度改革、技术培训、种植结构等方面详细说明了搞好垦区节水灌溉工作的关键。     

饮料中柠檬黄含量测定的不确定度分析

对饮料中的柠檬黄含量进行了测定和不确定度分析,通过对各影响因素的不确定度评定,试验重复性对饮料中合成着色剂的测量结果不确定度的影响最大,其次是样品处理回收率和标准曲线拟合引入的不确定度对试验结果也有较大的影响。结果表明:饮料中柠檬黄的含量为（103.5?3.5）mgkg,k＝2。      

Role of farmers' attitudes in adoption of irrigation in Saskatchewan

Adoption of a new technology, such as irrigation, is a complex phenomenon. Several factors of economic and social nature contribute to the farm-level decisions affecting adoption. In this study, the role played by attitudes of potential adopters towards irrigation and its subsequent adoption on their farm unit was estimated. Two models were estimated, one incorporating only adopters' socio-economic characteristics, and the other, only their attitudes towards irrigation. Results suggest that adopters' attitude, particularly with respect to economic and environmental effects of irrigation, were significant determinants of their decision to proceed with adoption of irrigation, and have a role to play in adoption of irrigation over and above that explained by socio-economic characteristics. In particular, these results suggest that negative perceptions with respect to economics of irrigation and those related to its detrimental impacts on environmental quality, particularly through soil salinity, may be significant deterrents for adoption of irrigation. The study suggests that planning of large scale water development projects, particularly those involving irrigation, must be cognizant of attitudes of potential adopters. Furthermore, during the planning stages, more attention should be paid to the development of proper educational programs, as well as extension packages, to ensure that potential adopters formulate correct attitudes towards the new technology.     

技工院校数学教学中培养学生应用能力的对策分析

数学作为一门基础性学科，在学生的各个学习阶段都起到了不可替代的作用，在工科院校中数学教学的重要性更是升到了一个新的高度。通过数学的学习，可以培养学生的应用能力和探究思维，通过对数学知识的学习和灵活运用，学生的综合能力会得到系统性的提高。对于数学的教学工作，应当做到有针对性、有目标，在教学工作中，充分做到对症下药、有的放矢，让学生通过对数学的学习，提高自身的综合能力，更好地为社会建设贡献力量。     

沼气在冬季温室生产中的应用

本试验通过沼气燃烧,提高冬季温室温度,促进西红柿生长发育.试验结果表明:增温可有效提高冬季温室温度,为西红柿越冬生产提供良好条件,有利于西红柿植株茎粗增加及果实膨大速率提高;可使西红柿坐果期提前10天左右,采收期延长20天左右,并提早上市.同时,增温可显著提高西红柿产量,亩增产800kg.     

四川简阳地区砂岩层中水分利用研究

分析了四川简阳地区砂岩和土壤中的水分运动特性和砂岩中储存的水分对土壤水分补给量的多少。对当地的砂岩和土壤进行了水分特征曲线的测定试验、入渗试验和蒸发试验,并采用研究中常用模型对试验结果进行了拟合,通过对拟合结果的分析,得出了当地土壤和砂岩的水分特性,总结出了该地区表面土层在缺水时水分很容易被下部砂岩层补给,砂岩中的水分是作物利用的重要水资源的结论。这对于充分利用当地水资源,合理确定类似地质条件地区灌溉定额,解决无灌溉条件丘陵区作物缺水问题,实现农业节水灌溉有一定的参考价值。     

Advances in application of climate prediction in agriculture

Agricultural ecosystems and their associated business and government systems are diverse and varied. They range from farms, to input supply businesses, to marketing and government policy systems, among others. These systems are dynamic and responsive to fluctuations in climate. Skill in climate prediction offers considerable opportunities to managers via its potential to realise system improvements (i.e. increased food production and profit and/or reduced risks). Realising these opportunities, however, is not straightforward as the forecasting skill is imperfect and approaches to applying the existing skill to management issues have not been developed and tested extensively. While there has been much written about impacts of climate variability, there has been relatively little done in relation to applying knowledge of climate predictions to modify actions ahead of likely impacts. However, a considerable body of effort in various parts of the world is now being focused on this issue of applying climate predictions to improve agricultural systems.

In this paper, we outline the basis for climate prediction, with emphasis on the El Niño-Southern Oscillation phenomenon, and catalogue experiences at field, national and global scales in applying climate predictions to agriculture. These diverse experiences are synthesised to derive general lessons about approaches to applying climate prediction in agriculture. The case studies have been selected to represent a diversity of agricultural systems and scales of operation. They also represent the on-going activities of some of the key research and development groups in this field around the world. The case studies include applications at field/farm scale to dryland cropping systems in Australia, Zimbabwe, and Argentina. This spectrum covers resource-rich and resource-poor farming with motivations ranging from profit to food security. At national and global scale we consider possible applications of climate prediction in commodity forecasting (wheat in Australia) and examine implications on global wheat trade and price associated with global consequences of climate prediction.

In cataloguing these experiences we note some general lessons. Foremost is the value of an interdisciplinary systems approach in connecting disciplinary knowledge in a manner most suited to decision-makers. This approach often includes scenario analysis based on simulation with credible models as a key aspect of the learning process. Interaction among researchers, analysts and decision-makers is vital in the development of effective applications — all of the players learn. Issues associated with balance between information demand and supply as well as appreciation of awareness limitations of decision-makers, analysts, and scientists are highlighted. It is argued that understanding and communicating decision risks is one of the keys to successful applications of climate prediction.

We consider that advances of the future will be made by better connecting agricultural scientists and practitioners with the science of climate prediction. Professions involved in decision making must take a proactive role in the development of climate forecasts if the design and use of climate predictions are to reach their full potential.     

Fate and transport of atrazine in a sandy soil in the presence of antibiotics in poultry manures

Pesticides degrade principally through biodegradation processes, whereas antibiotics kill microorganisms or inhibit their growth in soils and thus may affect the fate of pesticides. In this study, the impact of antibiotics on the degradation of atrazine in a sandy soil is investigated in lysimeters over a ninety-day period. Four treatments, monensin, narasin, salinomycin and non-antibiotic, were assigned in triplicate to twelve PVC lysimeters. Both soil and leachate samples were collected and analyzed at predetermined time intervals. In all treatments, atrazine was found to leach down through the soil profiles with the concentration level decreasing with depth, and only trace amounts of atrazine were found in the leachate. However, the statistical analysis of the results showed that all the three antibiotic treatments yielded a significantly slower dissipation of the atrazine level as compared to the non-antibiotic treatment; the mass balance analysis indicated an increased half-life of atrazine in the presence of antibiotics.     

北京典型灌区土壤和农产品多氯联苯污染风险评估

为明确北京东南郊灌区表层土壤和农作物多氯联苯(PCBs)含量和污染水平以及人体健康风险,2015年在该灌区采集了20个土壤样品和28个作物样品,利用气相色谱-质谱联用仪分析了样品中7大类PCBs含量。研究结果表明,灌区表层土壤PCBs质量比为ND(低于检出限)到0.711 776μg/kg,均值为0.43μg/kg,总体上土壤PCBs含量随污灌历史年限增加而增加。本研究区表层土壤PCBs含量处于较低水平,土壤未受到PCBs污染且其生态风险概率均小于10%。灌区采集的冬小麦籽粒、大葱、茄子、梨、白薯、芥蓝PCBs含量均低于实验检出限,未检出;夏玉米籽粒、菜心和油菜PCBs总量分别为0.17~0.47μg/kg、1.63μg/kg和5.91μg/kg。不同污灌历史年限并未显著影响夏玉米籽粒PCBs含量。本研究区农产品PCBs含量处于较低水平,均低于美国卫生及公共服务部建议限量。采集的土壤和农产品样品仅四氯联苯含量高于实验检出限,能检测出;一氯联苯到三氯联苯和五氯联苯到七氯联苯均低于实验检出限,未检出。本研究中成人和儿童PCBs致癌风险分别为8.49×10-7和4.66×10-7,非致癌风险分别为1.41×10-1和3.88×10-1,均低于US EPA规定限值,说明PCBs未对人群产生明显的健康危害。致癌危害和非致癌危害均以口-作物(玉米和蔬菜)为主,其对人体健康所造成的风险占总个人年风险的比例分别为99.79%~99.95%和99.81%~99.94%。