A new study by researchers at Rice University in Houston, Texas warns that expanded production of crops to produce biofuels could damage water resources. The researchers suggest policy makers take into account what they call the "water footprint" when encouraging biofuel development.
在美国德克萨斯州休斯敦市的莱斯大学，研究人员在新近发表的一份研究报告中警告说，越来越多地利用农作物生产生物燃料有可能破坏水资源。研究人员建议，决策者在鼓励生物燃料发展的同时，应当考虑到他们称之为“水足迹”的问题。
The study is titled The Water Footprint of Biofuels: A Drink or Drive Issue? The suggestion is that by using too much water to produce fuel, humankind might leave itself with not enough water to drink or to grow food.
这份报告的题目是《生物燃料的水足迹：一个关系到饮水还是开车的问题》。报告指出，将水资源过多地用于生产燃料，可能导致人类自身的饮用水和种粮用水变得缺乏。
The lead author of the study, Rice University Professor of Civil and Environmental Engineering Pedro Alvarez spoke to VOA by telephone from France, where he is attending an academic meeting. He says the water footprint consists of two elements. "Water shortages caused by a significant increase in fuel crop irrigation, and increased water pollution from related agro-chemical drainage and increased erosion and so on. The two impacts we refer to as the 'water footprint,'" he said.
该研究报告的主要作者、莱斯大学土木与环境工程教授佩德罗.阿尔瓦雷斯(Pedro Alvarez) 在接受美国之音采访时解释了所谓的“水足迹”。他说：“能源作物的灌溉大量增加，相关农用化学品以及水土流失造成的水污染恶化，这些都是导致水源短缺的主要因素。这就是我们所说的‘水足迹’。”
Alvarez says there are good reasons to continue programs to produce biofuels, such as reducing the need for imported oil and diversifying our sources of energy. But he says policy makers should provide incentives to producers to use crops that use less water and have less impact on the environment in the form of runoff of pesticides, fertilizers and other chemicals.
阿尔瓦雷斯说，减少石油进口并使能源来源多样化，都是推进生物燃料项目的正当理由。但是他又说，决策者要鼓励生产者种植用水较少的作物，并减少农药、化肥和其他化学品的使用，以减少对环境的不利影响。
"We want to try to use crops that deliver more energy with lower requirements for not just water, but also land and agro-chemicals. These are usually non-edible cellulosic crops," he said.
“我们希望推广那些不但用水较少、而且需要较少土地和化学品的农作物。这往往是些不可食用的纤维作物。”
The Rice University study also suggests that using corn to produce the alcohol fuel ethanol may not always be cost effective, especially in states where farmers have to use large amounts of fertilizer to produce the grain.
莱斯大学的报告指出，用玉米生产酒精燃料乙醇成本并不低。尤其是在那些农民们不得不使用大量化肥的州。
But Kristen Brekke of the American Coalition for Ethanol in Sioux Falls, South Dakota says the study does not take into account the growing yields farmers are producing by using technology and improved agricultural practices.
但是，总部设在南达科他州苏福尔斯市的美国乙醇燃料联合会的克里斯丁.布莱克(Kristen Brekke)说，该项研究忽略了一个情况，那就是农民们利用新技术和改善耕作方式以使产量不断增加。
"They are getting a lot more efficient; they have a lot better crop genetics and agronomic practices like no-till farming and things like GPS [satellite-dependent global positioning system]. That sort of technology allows them to put only the amount of fertilizer that is needed on a field and in the exact location that it is needed. USDA [the U.S. Department of Agriculture], for example, says that corn yields are expected to double in the next 25 years," she said.
布莱克说：“他们提高了生产效率，改良了作物品种，并运用诸如免耕直播及全球定位系统等手段改进耕作方式。 这些技术使人们只在必要的地方施用最少量的化肥。美国农业部预测，在未来的25年中，玉米产量将翻一番。”
But Brekke agrees with the Rice University study in that using corn for ethanol may not work well everywhere and that development of cellulosic ethanol from waste products and other plants makes sense. "The nice thing about cellulosic ethanol is that all areas of the country will be able to participate in that. Where it makes sense to grow corn, some of that corn is going to ethanol production, but in other areas of the country they will be able to use what they have locally available," she said.
但是，对于莱斯大学报告中所称，利用玉米生产乙醇燃料并非处处行得通这一点，布莱克表示同意。她也认为利用农业废料和其他纤维质作物生产乙醇言之有理。布莱克说：“利用纤维质作物生产乙醇的好处是它在全国各地都行得通。在适合玉米生长的地区，可以把部分玉米用来生产乙醇，但在国内其他地区，人们可以就地取材。”
The ethanol industry backs the use of the alcohol additive to gasoline as way of reducing petroleum consumption nationwide.
乙醇工业推动了酒精添加剂在汽油中的使用，在全国范围内降低了汽油的消费。
But Pedro Alvarez argues that it might be better for the environment as well as farmers to use the alternative fuel locally and not try to transport it long distances. He says that the growing world population might force policy changes not only in terms of water used for fuel crops, but also in terms of how water is used to produce the food we eat.
但是，阿尔瓦雷斯认为，更好的做法是就地取材生产替代燃料，以避免长途运输，这对农民和环境都有好处。他还说，全球人口增加将迫使各国不仅改变燃料作物的用水政策，也将改变粮食生产的用水政策。
"To make one kilogram of bread, let's say, you need 1,000 liters of water and to make one kilogram of meat you need 10,000 liters of water. The point here is that water is going to be a severe limiting factor - not only to economic development, but just to feed a growing population," he said.
“生产一公斤面包，比方说，需要用1000公升水；生产一公斤肉，需要用1万公升水。关键的问题是：水资源将变成一个严重的限制因素，不仅限制经济发展，而且会限制不断增长的人口的吃喝。”
Alvarez says population growth will drive the need to allocate water carefully for various food crops as well as livestock. Likewise, he says, it will be necessary to balance the goals of reducing oil consumption and supporting the income of farmers with the need to preserve the water that makes agriculture possible.
阿尔瓦雷斯说，人口增长会促使人们在粮食生产和家畜饲养方面更加小心地分配水资源。同样地，在减少石油消费、增加农民收入和确保水资源能够满足农业生产方面，的确有必要求得平衡。 |