推广节水灌溉是促进干旱地区农业发展的关键

我国是水资源贫乏的国家，人均占有量仅为世界人均占有量的25％．同时，我国又一个农业大国，每年农业缺水量高达300亿m3，受旱面积达到1300－2000hm2．1996年，我国因受干旱而减产粮食260亿kg．尽管如此，我国农业用水的利用率却很低，有效利用率只有30％－40％．所以从某种意义上说，农业的发展在很大程度上依赖于灌溉技术的发展．1节水灌溉技术节水灌溉技术是一项综合性的系统工程，它主要包括输水技术、喷油和做法技术、综合开发利用技术和优化调度管理技术．喷油比地面灌溉节水20％一30％，而且省时省力，不易堵塞，增产效果显著．田治…     

黄河流域农田灌溉节水措施浅析

黄河流域处于干旱半干旱地区，农业发展主要依靠灌溉，截止到1994年底，黄河灌域农田灌溉面积（含黄河下游引黄灌区）已达731万hm2，约占全流域总耕地面积的40％，耗水量占全河总耗水量的80％～90％。但是，由于管理水平、工程配套、灌水技术等多方面的原因，黄河流域农田灌溉水资源浪费现象严重。据有关资料分析，目前全流域灌溉定额为6000～15000m3／hm2，平均在9000m3／hm2以上。近年来，黄河水资源日益紧张，下游河道频繁断流，供需矛盾非常突出，这不仅束缚着沿黄经济带的迅速发展，也限制了黄河流域农田灌溉的进一步发展和壮大。因此…     

节水高产控制灌溉技术

控制灌溉具有明显的节水、高产效果。水稻控制灌溉可节水50％，增产10％；大面积推广运用可节水3000m3／hm2，增产750ks／hm2。小麦控制灌溉可节水65％，增产20％；大面积运用可节水2500m3／hm2，增产1000kg／hm2。水稻控制灌溉灌溉水的生产效率为2．85kg／m3；小麦为7kg／m3。该技术投资少，方法简单，易操作。分析了水稻、冬小麦控制灌溉的作物需水量的试验数据，提出了其技术规范。     

节水农业技术发展综述（续）

2节水农业技术及其现状与发展趋势由于全球性人口增长对粮食及其它农产品的需求量迅速增加，世界各国都积极采取各种措施，力求大幅度提高农作物产量。据近20多年的资料表明，世界上粮食增产中25％归功于扩大耕地面积，74％归功于提高单产。在单产的提高中，灌溉是非常重要的措施之一。因此在现有耕地上发展灌溉，提高单产，受到普遍的重视。根据联合国粮农组织统计，1992年，全世界法溉面积共计2，5亿hm2，比50年代初的1亿hm2扩大了一倍多。灌溉面积占世界总耕地的比重为18．54％，生产了世界粮食总产量的40％。而今后全世界进一步可开发与…     

试论今后50年的粮食需求与水利建设

建国40多年来，我国人口由5．5亿增加到12．5亿，年增长约1500万人，年增长率约1．80％；粮食产量由1100亿kg增加到4800亿kg，年均增加约80亿kg，年增长率约3．20％；人均粮食由每年200kg增加到384kg，年增长率约1．40％；同期耕地面积略有减少，灌溉面积与农业用水增长了两倍，年增长率约2．60％。到下个世纪中叶，人口将增加到16亿，年增长约640万人，年增长率约0．45％；人均粮食希望能从人均384kg提高到450kg，年增长率约0．28％，相应粮食则需从4800亿kg提高到7200亿kg，年均增加约45亿kg，年增长率约0．77％。虽然粮食需求的年增加量…     

新疆农机化的新发展

截至 2000年底，全区农机总动力达到 670KW，占农业总动力的 86％ (不含兵团，下同 )，较上年增长 4％；拖拉机拥有量 28.1万台。其中：大中型拖拉机 4.6万台，小型拖拉机 23.5万台，同比分别增长 2％和 3％；大中型配套农具 10.5万台 (架 )，小型配套农具 29万台 (架 )，大中型农具配套比 1： 2.3，小型农具比 1： 1.24，分别较上年增长 4.6％和 13.6％。农机化队伍 30余万人，农机总作业量达 5.15亿标准亩，机耕面积 217.7万 hm2,较上年增长 2％，机械化程度 92％；机播面积 197万 hm2，机械化程度 80％；机收面积 63.7万 hm2，机械化程…     

水稻节水灌溉

我国水稻生严面积3210万hm2，水稻总产量达1．862亿t，面积及总产量在世界各国中均占第一位。水稻是我国主要粮食作物之一，全国水稻产量约占粮食作物总产量的42％，稻田面积占全国粮食作物总面积的29％。我国水稻约8％分布在北方（淮河—秦岭—白龙江以北），虽然所占比重不大．但绝对面积达260万hm’，因此不容忽视这部分水稻。北方稻区处于干旱半干旱地区，水资源不足，水量供需矛盾日益严重，甚至有些地区由于缺水而难以维持继续种植。全国92％以上的稻田分布在南方，在该区域，水稻的灌溉用水量占总灌溉用水量的90％以上，虽然南方降水…     

回眸"九五"展望未来

1.“九五”期间晋城市农机化发展的突出特点(1)农机装备水平大幅度提高，农机结构趋向合理到2000年，晋城市农业机械原值达到8亿多元，农机总动力发展到155.2万kW，拖拉机保有量达到14622台，农用运输车达到47706辆，联合收割机达到297台；各类配套农机具达到23108台(件)。农业机械资产占到全市农业生产性固定资产的30％以上。(2)农机作业水平稳步上升晋城市的机耕面积已由1995年的13.5万hm2上升到14.2万hm2，机播面积由4.1万hm2上升到8.3万hm2，机收面积由3.0万hm2上升到5.1万hm2，分别比“八五”期末增长5.2％、102.4％和70％，耕、播、…     

美国的节水灌溉

1美国农业灌溉概况美国国土面积936万km2，耕地占19％，约1．8亿hm2，人口2．55亿，人均土地及耕地分别为3．7hm2和0．53hm2，分别为我国的4．7倍和8倍。美国灌溉面积约占耕地的12．5％，近2260万hm2，喷灌面积占总灌溉面积的37％，约840万hm2，在内布拉斯加、得克萨斯和明尼苏达等州推广面积较大，内布拉斯加州喷灌面积已达该州灌溉面积的一半。滴灌面积占总灌溉面积的4．2％，约为95．0万hm2，加州为16．8％，西部（密西西比河西，除加州）仅为3．7％。滴灌多用于水果、棉花和其他高附加值的经济作物。加州的柑桔和葡萄约70％～80％采用滴…     

1996～1997年度全国农田水利基本建设情况回顾

1996年入秋以后，各地认真贯彻国务院召开的全国农田水利基本建设电视电话会议和全国水利工作会议精神，加强领导，广泛发动群众，进一步增加投入，掀起了农田水利基本建设的高潮。截止1997年5月底，全国累计投入劳动积累工94亿个，搬运土石方116亿m3，投入水利建设资金397亿元，兴修水利工程228万项，分别比1995～1996年度同期增长19％、14％、36％、20％；新增灌溉面积120．6万hm2（1809万亩），改善灌溉面积499．6万hm2（7494万亩），新增节水灌溉面积123．5万hm2（1852万亩），新增除涝面积160．8万hm2（2412万亩），改造中低产田191．7…     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。