It’s early August and the countryside appears peaceful. Planting庄稼 has long been finished and the fields are alive with strong, healthy crops. Soybeans and wheat are flourishing under the hot summer sun, and the corn, which was “knee-high by the fourth of July”, is now well over six feet tall. Herds of dairy and beef cattle are grazing peacefully in rolling pastures which surround big, red barns and neat, white farmhouses. Everything as far as the eye can see radiates a sense of prosperity. Welcome to the Midwest—one of the most fertile agricultural regions of the world.
八月上旬，乡间田野呈现出一派宁静的景象。春耕播种早已结束，地里的庄稼在茁壮成长，大地充满了微生机。大豆小麦在夏日的骄阳下长势喜人。在７月４日国庆时，玉米还高不没膝，而现在已有六英尺多高了。成群的奶牛和菜牛在绵延起伏的草场上安静地啃食青草，在牧场的中间座落着几栋红色大牲口棚和几幢整洁的白色住房。放眼望去，到处都展现着繁荣的景象。欢迎到中西部来――这里是全世界最富饶的农业地区之一。
The tranquility of the above scene is misleading. Farmers in the Midwest put in some of the longest workdays of any profession in the United States. In addition to caring for their crops and livestock, United States. In addition to caring for their crops and livestock, they have to keep up with new farming techniques, such as those for combating soil erosion and increasing livestock production. It is essential that farmers adopt these advances in technology if they want to continue to meet the growing demands of a hungry world.
上面所描述的宁静景象会使人产生错觉。其实中西部的农民在美国所有的职业中投入的工作量最大。除了照料庄稼和牲畜外，他们还得跟上最新的农业技术，比如防止土壤侵蚀的技术、增加牲畜产量的技术。如果农民想继续满足这个充满饥饿的世界日益增长的食品需求，那他们采用这些先进技术就是至为关键的。
Agriculture is the number one industry in the United States and agricultural products are the country’s leading export. American farmers manage to feed not only the total population of the United States, but also millions of other people throughout the rest of the world. Corn and soybean exports alone account for approximately 75 percent of the amount sold in world markets.
农业是美国的第一产业，农产品是美国的主要出口产品。美国农民不但要努力为本国所有人提供食品，而且还要为世界其他地区百万人提供食品。仅玉米和大豆两项出口产品就大约占世界市场销售总量的75％。
This productivity, however, has its price. Intensive cultivation exposes the earth to the damaging forces of nature. Every year wind and water remove tons of rich soil from the nation’s croplands, with the result that soil erosion has become a national problem concerning everyone from the farmer to the consumer.
这种集约耕种使土壤受到了自然界破坏力量的侵袭。每年自然界的风和雨水都要从这个国家耕地上带走大量肥沃的土壤，结果土壤侵蚀现已成为一个关系到从农民到消费者每一个人的全国性问题。
Each field is covered by a limited amount of topsoil, the upper layer of earth which is richest in the nutrients and minerals necessary for growing crops. Ever since the first farmers arrived in the Midwest almost 200 years ago, cultivation and, consequently, erosion have been depleting the supply of topsoil. In the 1830s, nearly two feet of rich, black top soil covered the Midwest. Today the average depth is only eight inches, and every decade another inch is blown or washed away. This erosion is steadily decreasing the productivity of valuable cropland. A United States Agricultural Department survey states that if erosion continues at its present rate, corn and soybean yields in the Midwest may drop as much as 30 percent over the next 50 years.
每块耕地的表层土壤都是有限的，而庄稼生长所必需的养分和矿物质在表层土壤最丰富。自从第一批农民在近二百年前来到中西部地区以来，农耕及由此引起的土壤侵蚀一直在消耗着表土资源。在19世纪３０年代，中西部地区肥沃的黑土层还有近二英尺厚，而今天的厚度则只有八英寸了，而且每隔十年就有一寸被刮农业部的一项调查显示，如果按目前这个速度侵蚀下去，那么５０年后美国中西部地区的玉米和大豆产量将下降30％。
So far, farmers have been able to compensate for the loss of fertile topsoil by applying more chemical fertilizers to their fields; however, while this practice has increased crop yields, it has been devastating for ecology. Agriculture has become one of the biggest polluters of the nation’s precious water supply. Rivers, lakes, and underground reserves of water are being filled in and poisoned by soil and chemicals carried by drainage from eroding fields. Furthermore, fertilizers only replenish the soil; they do not prevent its loss.
迄今为止，农民只能靠向田地里施用更多的化肥来弥补肥沃表层土被侵蚀所造成的损失。尽管这种作法提高了粮食产量，但对生态却是场大灾难。农业已成为宝贵的水资源的最大污染源之一。从受侵蚀的田地里的排水系统中排出的水夹杂着泥土和化学物质（化肥），这些水正在流入并污染着河流、湖泊及地下水资源。另外化肥只能补充土壤中的养分，却不能防止其流失。
Clearly something else has to be done in order to avoid an eventual ecological disaster. Conservationists insist that the solution to the problem lies in new and better farming techniques. Concerned farmers are building terraces on hilly fields, rotating their crops, and using new plowing methods to cut soil losses significantly. Substantial progress has been made, but soil erosion is far from being under control.
很明显，为了避免最终出现的生态灾难，应该采取别的措施。自然资源保护论者坚持认为出路在于推出更新更好的农业技术。为了大幅度地减少土壤损失，农民正在山坡地上修梯田，轮种庄稼并采用新的耕作方法。这一切都取得了重大成就，但土壤侵蚀问题仍远未得到控制。
The problems and innovations of the agricultural industry in the Midwest are not restricted to growing crops. Livestock raising, which is big business in the certral region of the United States, is also undergoing many changes. Recent developments in technology have enabled farmers to raise not only healthier animals, but more animals as well. By employing the techniques of super-ovulation, artificial insemination, and embryo transfer, farmers can more than triple the number of offspring produced by a single cow per year.
中西部地区农业产业的问题及革新并不只局限在增加粮食上。家畜养殖是美国中部地区的一大产业，而且现在也正在经历着种种变革。技术上的最新发展已使农民不但能饲养出健康的家畜来，而且还能增加其数量。通过采用增多排卵、人工授精和胚胎移植技术，农民可以使每母牛产崽数增加两倍多。
The procedure of accomplishing this remarkable feat is as follows. First, the farmer chooses a cow on the basis of certain valuable traits, such as rapid weight gain or high milk production. A veterinarian then injects the cow with hormones which cause the animal to super-ovulate, that is, to produce more eggs, or “ova”, than the usual one or two. As many as ten or more ova may be released in one super-ovulation.
实施这项了不起的技术的过程如下：首先，农民根据某些有价值的特性，比如增重快或产奶量高而挑选出一头母牛，之后兽医给这头母牛注射能促其增加排卵的激素（荷尔蒙），就是说要使其排出比正常情况下１－２个更多的卵子或卵细胞。在一次增加排卵中能够排出多达10个甚至更多的卵细胞。
While the ova are moving down the Fallopian tubes toward the uterus, about five days after super-ovulation, the cow is artificially inseminated with semen from a prize bull. If the insemination is successful, the eggs are fertilized and become living embryos, each of which has the potential to develop into a calf.
大约在为增加排卵而注射激素的５天后，当卵子顺着输卵管向子宫移去时，就用优种公牛的精液对母牛进行人工援精。如果授精成功，卵了受精并成活为胚胎，每个胚胎都有可能长成一牛犊。
Next comes the process of embryo transfer. After the embryos have developed in the uterus for six to eightdays, they are carefully removed and examined for defects. Each healthy embryo is then implanted in the uterus of a different cow, where it continues to develop. Nine months later the surrogate mother gives birth to a healthy calf to which she is not genetically related.
下一步就是胚胎移植。当胚胎在子宫发育６至８天后，要把它们小心地取出来并检查是否有缺陷，之后把每一个健康的胚胎移植到不同的母牛子宫内，在那里继续发育成长。９个月后代孕母体就会产下一头健康的小牛犊，代孕母体与这头小牛犊并无遗传关系。
The result of the entire procedure is that a farmer can increase the size of a herd of cows at a rate which was previously impossible. Although three to four calves are the average, as many as ten or more may be produced from the embryos of one mother cow. The possible applications of these techniques are overwhelming when one considers that by freezing an embryo until its sister embryo has been born and become sexually mature, it is even possible for a cow to give birth to its identical twin sister!
整个过程的结果就是农民能够以先前不可能有的速度增加其牛群的数量。虽然一头母牛的胚胎通常产３到４头小牛，但多时可达10头或10头以上。这种技术的应用可能性是极大的。当人们想到用冷冻办法先把一只胚胎冷冻起来，等到它的姐妹胚胎降生并性发育成熟时再移植其体内，那么甚至都可能让一头母牛产出一头和它一模一样的母牛来。
As the world’s population continues to increase, farmers will be called upon to produce more and more life-sustaining food. Constant technological advances in soil conservation and livestock production will be required to keep pace with this ever-growing need. One concern, however, is that while this technology is solving old problems, it may be creating new ones in the process.
随着世界人口不断增多，农民需要生产越来越多的维持生活的食物。在土壤保护和家畜生产方面要求技术要不断革新，以便满足这种日益增长的需求。但有一点需予以注意，即技术在解决老问题的同时也许会在其过程中产生出新的问题.