这片农田多丘陵，而且灌溉条件很差。
灌溉产生的多余水分渗入地下水。
Excess water from irrigation sinks down into the water table.
干旱地区需要灌溉才能使作物生长。
然而，灌溉用水的来源往往不是可持续的。
However, water used in irrigation is often sourced unsustainably.
他们在特奥蒂瓦坎山谷广泛灌溉的需要增加了。
They increased the need for extensive irrigation in the Teotihuacán Valley.
某些灌溉措施会降低土壤质量，降低农业生产力。
Certain irrigation practices degrade soil quality and reduce agricultural productivity.
运河的小堵塞或崩塌会阻塞错综复杂的灌溉网络。
Small blockages or collapses of the canal would choke the intricate irrigation networks.
这些管道被认为是为灌溉地表而修建的运河系统。
The lines were thought to have been a system of canals that had been built to irrigate the surface.
利用效率低的原因是采用了中国一些传统的灌溉方式。
The low utilization efficiency has resulted from the adoption of some traditional Chinese irrigation methods.
最重要的是，亚马逊河灌溉着地球上最大的热带雨林。
Most important of all, the Amazon irrigates the largest tropical rainforest on earth.
采用咸淡水交替灌溉可以降低土壤含盐量，增加棉花产量。
Irrigation with saltish and fresh alternatively can decrease soil salt content and increase cotton yield.
唐娜帮助村民们规划了一个灌溉工程，还建议他们种庄稼。
Donna helped the people of the village to organize an irrigation project, and she also advised them on planting crops.
该项目资助小型灌溉系统、支路和其他类型的社区基础设施。
The project finances small scale irrigation systems, feeder roads and other types of community infrastructure.
只有使用现代的灌溉方法，我们才能减少农业用水短缺的情况。
Only by using modern irrigation methods can we reduce water shortage in agriculture.
相反，美国41%的水投向了农业，并几乎全都用在了灌溉上。
In the United States, by contrast, 41% water goes for agriculture, almost all of it for irrigation.
正是这点使得灌溉的统筹，特别是建造运河以疏导和保护水，变得至关重要。
It was this that made the organization of irrigation, particularly the building of canals to channel and preserve the water, essential.
南非中部，一群玉米农挤成一团，围着一名农学家和他放在灌溉机旁的电脑。
A group of corn farmers stands huddled around an agronomist and his computer on the side of an irrigation machine in central South Africa.
在贫穷、干旱的地区，未经处理的废水是让农民维持生计的唯一可用灌溉资源。
In poor, dry regions, untreated wastewater is the only viable irrigation source to keep farmers in business.
这种情形始于在目标地区（如废弃矿井或被污水污染的灌溉池）种植超积累物种。
This scenario begins with the planting of hyperaccumulating species in the target area, such as an abandoned mine or an irrigation pond contaminated by runoff.
滴灌，或者“微”灌溉，顾名思义，是更吝啬于水，把水一滴一滴地滴到植物的根部。
Drip, or "micro" irrigation, as the name suggests, is stingier with the water, delivering it to the roots of plants drop by drop.
更好的灌溉可以显著提高作物产量；目前，全球约40%的粮食供应都来自于灌溉地。
Better irrigation can dramatically improve crop yield and about 40% of the world's food supply is currently derived from irrigated land.
最后，持续增加的人口很可能是通过不断扩大灌溉土地的面积和规模而得到食物供应的。
Finally, the growing population was probably fed by increasing the number and size of irrigated fields.
长江流经多种不同的生态系统，是诸多濒危物种的栖息地，灌溉了中国五分之一的土地。
As a habitat for many endangered species, the Yangtze River flows through diverse ecosystems and irrigates one-fifth of China's land.
随之而来的灌溉农业的迅速发展，特别是从20世纪50年代以来，改变了该区域的经济。
The ensuing rapid expansion of irrigation agriculture, especially from the 1950s onward, transformed the economy of the region.
国家必须修建更多的灌溉工程来养活不断增长的人口，这为精英阶层带来了更多的权力和财富。
More irrigation works would have to be built to feed the growing population, and this resulted in more power and wealth for the elite.
在许多国家，数以百万计的灌溉井现在从地下水源抽水的速度，超过了降雨所能再次填满的速度。
Millions of irrigation wells in many countries are now pumping water out of underground sources faster than rainfall can refill them.
在许多国家，数以百万计的灌溉井现在从地下水源抽水的速度，超过了降雨所能再次填满的速度。
Millions of irrigation wells in many countries are now pumping water out of underground sources faster than rainfall can refill them.
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