重庆市红层地区饮用水水质问题及饮水对策研究

重庆市红层地区是我国西部缺水地区之一,面积约4万k㎡,占全市辖区面积的48%,涉及33个区、县.农村缺水人口分布在红层区的约380万.人畜饮水解困任务艰巨.虽然实施浅井解困实现了突破,但部分浅井水质不达标,给缺水地区的浅机井人畜饮水解困提出了新的问题.针对重庆市红层浅井解困中出现的水质问题进行研究,并初步提出解决方案,供实施人畜饮水解困工程参考.     

彭曼模型在预测作物需水量中的应用——以沈阳地区为例

采用水量平衡法实测和Penman-Menteith模型模拟对沈阳地区在采用新兴的高产品种情况下的作物需水量进行对比研究,从而验证了彭曼模型在沈阳地区应用的有效性,并为沈阳地区作物需水情况及确定作物灌溉制度的进一步研究提供基础资料.     

集雨节灌旱地春小麦最佳补灌时期的研究

在宁夏南部半干旱地区 ,对春小麦不同时期灌水对小麦产量及水分利用效应进行了研究 ,得出覆膜春小麦不同生育期灌水 3 0 mm,与不灌水相比 ,均有增产效果。其中在拔节期灌水 3 0 mm产量可增加 3 71 .1kg/hm2 ,水分利用率提高 1 1 .2 %。考虑降雨分布等因素 ,认为拔节期是地膜春小麦集雨节灌最佳补水时期     

砒砂岩地区人工沙棘群落结构及多样性分析

针对砒砂岩地区困难立地生态恢复与合理利用问题,选取2～10a的沙棘人工林为研究对象,对不同林龄群落结构及植物多样性进行比较研究.结果表明:砒砂岩地区人工种植沙棘后,随着沙棘林龄的增长,植物种类逐步增加.在造林初期,林下草本植物以一年生且旱生的植物地蔷薇为优势种群;造林3a后,以多年生植物赖草、阿尔泰狗娃花为主要优势种;...     

农村电网智能化改造解决方案

随着国民经济的不断发展，我国农村地区在进行电网改造的过程中，一定要结合时代的发展要求，在对电网的无功功率进行分析和研究的过程中，不仅要对电网的供电质量进行重点考虑，还需要对电网的相关参数进行系统化分析。对农村电网智能改造的整体解决方案进行了研究。      

川渝地区温室结构设计与优化

川渝地区的气候条件独特,至今仍无合适的温室类型.虽然华北型温室在这一地区广泛使用,但并不能很好地适应当地的条件,相关的研究也十分缺乏.随着人民生活水平不断提高,蔬菜、水果、花卉和草坪等的需求量不断增加,设施园艺在该地区得到迅速发展,大量的问题亟待解决.为此,根据本地冬季光照不足、夏季高温高湿以及风雪载荷小的气候特点,确定本地区温室结构类型尺寸,按照优化设计理论对温室的结构进行优化设计是非常必要的.     

冀西北高寒半干旱地区保护性耕作技术

我国冀西北高寒半干旱地区位于内蒙古高原与华北农区间的交错带,自然条件较为恶劣,因此保护性耕作是我国北方旱区发展的重要出路.目前,保护性耕作研究在世界范围内已相当深入.为此,就冀西北面临的问题、保护性耕作技术的内容以及存在的问题进行了阐述.     

大古水电站RCC重力坝施工期温控防裂研究

大古水电站地处高海拔地区,气候环境复杂,施工期温控防裂是该工程设计施工的关键技术问题.选取5号边坡坝段为研究对象,模拟坝体浇筑全过程,考虑混凝土徐变,采用三维有限元法进行数值模拟仿真计算,研究坝体温度场及应力特性,提出温控防裂措施.研究结果表明,高海拔地区碾压混凝土筑坝,具有低温季节浇筑混凝土上下游坝面开裂风险高,高温...     

新时期农村地区教育公平现状及对策研究

在现代化发展的过程中,必须要保证教育的公平性.所以在当前的发展环节里,农村地区的教育公平成为了研究的重点.文章主要探讨了农村地区教育公平的现状,并提出了相关的对策和建议,希望能够为今后农村地区的教育发展带来参考和借鉴.     

陕北地区石油开采理论用水定额研究

陕西省石油开采主要集中在陕西北部的延安、榆林两市(陕北地区),石油开采量约占全国总量的13.4％,水资源利用量较大,为贯彻落实最严格水资源管理制度和建设节水型社会,有必要对陕北地区石油开采用水定额进行研究.本文采用物质平衡法和注采比法进行理论分析和实例计算,研究表明:在特定条件下,两种方法计算结果基本相同;同时考虑辅助...     

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%。