外文翻譯--節(jié)水灌溉(完整版)
【正文】 umid areas average annual rainfall is basically in line with planting drought crop water demand, but due to the uneven distribution of precipitation, dry years and dry season water shortages more。但是地面灌溉技術(shù)也在不斷發(fā)展不斷完善，所以最近也有許多比傳統(tǒng)地面灌溉技術(shù)更節(jié)水的方法。在我國(guó)用得較多的有以下幾種：固定管道式噴灌、 .半移動(dòng)式管道噴灌、滾移式噴灌支管、時(shí)針式噴灌機(jī)、大型平移噴灌機(jī)、紋盤式噴灌機(jī)以及中、小型噴灌機(jī)組等。微噴頭仍有堵塞問(wèn)題，因此也要對(duì)過(guò)濾問(wèn)題給予足夠的重視，每公頃造價(jià)與固定式滴灌相仿。 二．影響節(jié)水灌溉方式選擇的因素 (一 )氣候條件 我國(guó)由東南沿海向西北內(nèi)陸，一般劃分為濕潤(rùn)地區(qū)、半濕潤(rùn)地區(qū)、半干旱地區(qū)和干旱地區(qū)，隨著干燥度的遞增，農(nóng)作物對(duì)灌溉的依賴程度也相應(yīng)遞增。平原下部湖濱和濱海區(qū)，地勢(shì)低平，土質(zhì)粘重，地表和地下徑流排泄不暢，在干旱氣候條件下，地下水礦化度高，開發(fā)利用困難，土壤鹽漬化嚴(yán)重。在采用節(jié)水灌溉方法的條件下，要達(dá)到的灌溉深度為０．４－０．５米， 水源充足時(shí)可達(dá)０．８－１．０米。幼樹應(yīng)少灌水，結(jié)果果樹可多灌水。一是通過(guò)農(nóng)業(yè)耗作栽培技術(shù)和修筑梯田、地埂等，減少坡地水土流失和土壤水分蒸發(fā)；二是在沖溝上修筑塘壩，或在適當(dāng)?shù)攸c(diǎn)修筑水窖，攔蓄徑流，解決飲水和小面積灌溉用水；三是在大的沖溝和支流上修水庫(kù)，集中控制徑流，通過(guò)引水工程將各個(gè)孤立的塘壩溝通，形成長(zhǎng)藤結(jié)瓜 式的灌溉系統(tǒng)，提高雨水利用率和灌溉用水保證率。最近在國(guó)外引進(jìn)采用廢輪胎加工成的多孔滲流管，并進(jìn)行小面積試點(diǎn)，但是微孔滲流管的堵塞是一個(gè)嚴(yán)重的問(wèn)題，未經(jīng)長(zhǎng)時(shí)間試驗(yàn)檢驗(yàn)不 宜貿(mào)然推廣。對(duì)灌溉水一定要認(rèn)真地進(jìn)行過(guò)濾和處理。 (又稱膜孔灌 ) 在地膜上做成溝狀，水就在膜上流動(dòng)，到作物長(zhǎng)出孔處才滲入土地，這樣灌水效率高，一般可節(jié)水 25%～ 35%，增產(chǎn) 15%～ 20%，又不要專門的設(shè)施。 repair reservoirs in the gullies and tributaries, centralized control runoff diversion project isolated tangba munication, formation of Chodo Jieguairrigation systems, improve rain water utilization and irrigation water to ensure rate. the use of surface water resources conditions Plain areas and open mountain basin, water conditions were better, but different parts have significant differences. Piedmont sloping plain terrain slope, coarse sediment, 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 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 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 mediumsized irrigation and well irrigation area in the plains area, due to the different parts of which the landforms, water conditions and acpanying drought waterlogging, salinity and other disasters also vary from place to place. specific planting Fruit trees, irrigation quota vary according to the type of fruit trees, varieties and rootstock characteristics, age size. Droughttolerant tree species, such as jujub
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