节水灌溉外文翻译

1、本科毕业（设计）论文外文文献翻译学 院： 城乡建设学院 专业班级： 农业水利工程0901班 water-saving irrigation1. existing water-saving irrigation methodsirrigation methods, field water distribution method is how to have been sent to the farms, the irrigation water is evenly distributed to the active layer of the crop root. irrigation water

2、 is the means by which to enter the active layer of roots, irrigation methods can be divided into surface irrigation, sprinkler irrigation, micro-irrigation and underground irrigation.1.1 surface irrigationsurface irrigation is an ancient traditional irrigation method, in general, it is as compare w

3、hether water-saving basis points. surface irrigation technology are constantly develop and constantly improve, so there are many more water-efficient than traditional surface irrigation technology.1.1.1 new furrow irrigation toolstraditional furrow irrigation with artificial opening from the distrib

4、ution channel water into the furrow, it is neither accurate and inconvenient, and often cause the field of water loss due to water port leakage countries have already adopted the siphon (for open channel water ) or gate hole pipe (aqueduct) drainage, china has done a number of tests, proven to impro

5、ve field water utilization rate of 5% to 10%.1.1.2 surge irrigationmodern foreign developed wave chung (groove) border irrigation or intermittent ditch (furrow) irrigation, traffic control into the ditch (furrow) is intermittent water and then put a period of time (a few minutes or tens of minutes)

6、to field stop the water for some time (a few minutes or tens of minutes), and so forth, so that you can make along the ditch (furrow) the length direction of the water distribution is more uniform. fields of water utilization up to 80% to 90%.film hole irrigation (also known as the film hole irrigat

7、ion)gully, made on the film of water flow in the membrane, crops grow hole to penetrate the land, so that irrigation efficiency is high, generally water-saving 25% to 35%, an increase of 15% to 20%, they do not specifically facilities.1.2 irrigationsprinkler to spray through the air, due to the pres

8、sure of the commonly used pressure aqueduct. in general, its obvious advantages irrigation uniformity, less of farmland, save manpower, strong adaptability to the terrain. the main disadvantage is influenced by wind, high investment in equipment. more in our country are the following: fixed pipe spr

9、inkler, the semi-mobile pipeline sprinkler irrigation, a rolling shift sprinkler manifold, when the needle irrigation machine, a large pan spray irrigation machine, grain irrigation machine in microirrigators units and so on.1.3 drip irrigationirrigation water with a small plastic tube directly sent

10、 to the the meike crop roots near the water drip out slowly by drippers, a sophisticated irrigation methods, only need water to irrigation can truly only irrigation crop instead of filling the land. and can be a long time in the crop root zone moisture in the optimal state, so to save water and incr

11、ease production. but its biggest drawback is the dripper out flow orifice is small, the flow rate is low, so serious congestion problems. irrigation water must be carefully filtering and processing. at present, china has only noticed to prevent physical clogging equally serious clogging the biologic

12、al and chemical clogging problem has not been taken seriously enough. the main way of drip irrigation: fixed-ground drip irrigation, semi-fixed-ground drip irrigation. membrane under irrigation, drip irrigation and other underground.1.4micro-sprinkler irrigationsome places called mist irrigation, an

13、d drip irrigation similar too easy just to overcome the dripper disadvantage of clogging the drippers to micro sprinklers, micro-sprinkler flow orifice large, large number of traffic flow rate faster unlike drippers so easy to plug, but the traffic has increased, capillary accordingly should bold so

14、me 1 to 2 micro sprinklers installed in every crop or tree usually can meet the needs of irrigation. micro nozzle still clogged filtration problems, and therefore should be given adequate attention, the cost per hectare is similar to fixed-drip irrigation. gradually replaced by drip irrigation micro

15、 sprinkler irrigation in a foreign country. especially suitable for irrigated orchards.1.5 subsurface irrigationsimilar to the subsurface irrigation and underground drip, just the dripper all buried in the underground seepage head instead, the seepage head of water unlike drippers as drop by drop ou

16、tflow, but slowly seepage, such seepage head is not easy soil particles and root blockage. recently introduced in a foreign country using waste tires processed into porous percolation pipe, and the pilot of a small area, but the clogging of the micropores seepage pipe is a serious problem, without t

17、he test to test for a long time should not be hastily promotion.1.6underground irrigationthe underground irrigation irrigation is a method to control the water table. to irrigation groundwater table elevation to the water can enter the height of the root activity layers, the ground remains dry, so v

18、ery provincial water, no irrigation, groundwater levels drop down. the limitations of this approach, only the root activity layers impermeable layer caixing.2. select the factors that affect water-saving irrigation methods2.1 weather conditionschina from the southeast coast to the inland northwest,

19、generally divided into sub-humid areas, semi-humid areas, semi-arid and arid regions, with dryness incremental, the dependence of crop irrigation is incremented accordingly. humid regions for many years the average annual rainfall is greater than the cultivation of dry crops in the field water consu

20、mption, water resources total more than just a lack of precipitation in the dry season and drought years, supplemental irrigation is required; semi-humid areas average annual rainfall is basically in line with planting drought crop water demand, but due to the uneven distribution of precipitation, d

21、ry years and dry season water shortages more; semi-arid areas average annual rainfall can not meet the crop water requirements, if there is no irrigation, agricultural production is very unstable, such areas such as irrigation, wasteland farming, the destruction of natural vegetation, can easily cau

22、se desertification; rainfall is scarce in arid regions, irrigation agriculture, water scarcity of such areas, river runoff from the alpine rain and snow melt water, industry and agriculture not only depend on the development and survival of the natural vegetation along the river channel near river w

23、ater for irrigation, and therefore reference, must take into account the natural ecological water. 2.2 the topography and hydrogeological conditionstopography and hydrogeological conditions affecting the natural distribution of rainwater, will also affect the pattern of water-saving irrigation. grou

24、nd on steep mountain hilly area prone to soil erosion and drought, water-saving irrigation to adopt comprehensive measures. cultivation technology and terracing, field ridges through agricultural consumption, reduce the sloping soil erosion and soil evaporation; gullies on the construction of embank

25、ments, or in suitable locations for the construction of water cellars, storing runoff solve drinking water and a small area irrigation water; repair reservoirs in the gullies and tributaries, centralized control runoff diversion project isolated tangba communication, formation of chodo jiegua-irriga

26、tion systems, improve rain water utilization and irrigation water to ensure rate.2.3 the use of surface water resources conditionsplain areas and open mountain basin, water conditions were better, but different parts have significant differences. piedmont sloping plain terrain slope, coarse sediment

27、, runoff smooth, rich groundwater recharge, water quality, is conducive to the development and utilization. slowing the central plains terrain slope sediments thinning increased level surface several times due to river flood diversion, post depression to staggered, affect runoff excretion increased

28、groundwater salinity under arid climatic conditions, soil there will be varying degrees of salinization phenomenon. the plains lower part of the lakeside and coastal area, low and flat, the soil is heavy clay, surface and underground runoff, poor drainage, arid climatic conditions, high salinity of

29、groundwater development and utilization of difficulties, serious soil salinization. this region in the river downstream, dry season, the rivers and the rainy season is threatened by the flood, so building large and medium-sized irrigation and well irrigation area in the plains area, due to the diffe

30、rent parts of which the landforms, water conditions and accompanying drought waterlogging, salinity and other disasters also vary from place to place.2.4 specific plantingfruit trees, irrigation quota vary according to the type of fruit trees, varieties and rootstock characteristics, age size. droug

31、ht-tolerant tree species, such as jujube, chestnut and rootstock species with lower water requirements the irrigation quota can be as small; poor drought tolerance of species, such as grapes, apples, pears, irrigation quota should be larger. the saplings should be less irrigation, the results of fru

32、it trees can be more than irrigation. saudi orchards should small water more than irrigation. saline land orchard irrigation should be noted that the groundwater level, in order to prevent the return of salt, returned to base. generally into one of the most suitable age fruit trees irrigation, soil

33、moisture completely wet fruit tree roots within appropriate. under the conditions of use of water-saving irrigation methods, irrigation to reach a depth of 0.4-0.5 meters, plenty of water up to 0.8-1.0 meters.to mature vine irrigation, mainly in the grape growing infancy, before and after flowering,

34、 berry enlargement period and grapes after harvest period, the general irrigation 5-7 times.节水灌溉一现有的节水灌溉方法灌水方法即田间配水方法，就是如何将已送到田头的灌溉水均匀地分布到作物根系活动层中去。按灌溉水是通过何种途径进入根系活动层，灌水方法可分为地面灌溉、喷灌、微灌和地下灌溉。(一)地面灌溉地面灌溉是古老的传统的灌水方法，一般说来它是作为比较是否节水的基点。但是地面灌溉技术也在不断发展不断完善，所以最近也有许多比传统地面灌溉技术更节水的方法。1.新的沟畦灌水工具传统的沟畦灌水是用人工从配水渠开

35、口放水入沟畦，这样既不准确又不方便，而且常因放水口渗漏造成水的田间损失，国外早已采用虹吸管(用于明渠输水的情况)或闸门孔管(用于管道输水的情况)放水，我国已做了一些试验，证明可提高田间水利用率5%10%。2.波涌灌溉近代国外又研究出波涌(沟)畦灌或称间歇沟(畦)灌，就是控制放入沟(畦)的流量是间歇的，向田间放一段时间(几分钟或几十分钟)的水然后停止放水一段时间(几分钟或几十分钟)，如此反复，这样可以使沿沟(畦)长度方向的水量分布更加均匀。田间水利用率可达80%90%。3.膜上灌(又称膜孔灌)在地膜上做成沟状，水就在膜上流动，到作物长出孔处才渗入土地，这样灌水效率高，一般可节水25%35%，增产

36、15%20%，又不要专门的设施。(二)喷灌喷灌是通过空中进行喷水，由于需要压力所以常用压力管道输水。一般说来，其明显的优点是灌水均匀，少占耕地，节省人力，对地形的适应性强。主要缺点是受风影响大，设备投资高。在我国用得较多的有以下几种：固定管道式喷灌、.半移动式管道喷灌、滚移式喷灌支管、时针式喷灌机、大型平移喷灌机、纹盘式喷灌机以及中、小型喷灌机组等。(三)滴灌是用小塑料管将灌溉水直接送到每棵作物根部的附近，水由滴头慢慢滴出，是一种精密的灌溉方法，只有需要水的地方才灌水，可真正做到只灌作物而不是灌土地。而且可长时间使作物根区的水分处于最优状态，因此既省水又增产。但其最大缺点就是滴头出流孔口小，流

37、速低，因此堵塞问题严重。对灌溉水一定要认真地进行过滤和处理。目前我国还都只注意到防止物理堵塞，而同样严重的生物堵塞和化学堵塞问题尚未引起足够的重视。滴灌的主要方式有：.固定式地面滴灌、半固定式地面滴灌、.膜下灌、地下滴灌等。(四)微喷灌有的地方称之为雾灌，与滴灌相似，只是为了克服滴头太易于堵塞的缺点，将滴头改为微喷头，由于微喷头出流孔口大一些，流量大一些，流速快一些，所以不像滴头那么容易堵塞，但流量加大了，毛管相应也要加粗些，在每棵作物或树下装12个微喷头一般即可满足灌溉的需要。微喷头仍有堵塞问题，因此也要对过滤问题给予足够的重视，每公顷造价与固定式滴灌相仿。在国外有逐渐以微喷灌取代滴灌的趋势。特别适用于灌溉果园。(五)渗灌渗灌与地下的滴灌相似，只是用渗头代替滴头全部埋在地下，渗头的水不像滴头那样一滴一滴地流出，而是慢慢的渗流出来，这样渗头不容易被土粒和根系所堵塞。最近在国外引进采用废轮胎加工成的多孔渗流管，并进行小面积试点，但是微孔渗流管的堵塞是一个严重的问题，未经长时间试验检验不宜贸然推广。(六)地下灌溉地下灌溉是用控制地下水位的方法进行灌溉。在要灌溉时把地下水位抬高到水可以进入根系活动层的高度，地面仍保持