This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
Charles Darwin is, most famously, the author of The Origin of Species. But the last book he ever wrote gets far less attention today. It's called The Formation of Vegetable Mould through the Action of Worms. And earthworms were a passion: he wrote about their habits, their soil-tilling abilities, and even kept pots of worm-filled soil in his study.
But his fascination was met with ridicule by some. "There's a famous cartoon where Darwin as an old man is in the middle. He evolves from monkeys and the monkeys evolved from earthworms."
Olaf Schmidt is a soil ecologist at University College Dublin. And not among those who would criticize Darwin for his interests. "I love earthworms, earthworms are brilliant. They're our friends, they're really important."
One particularly interesting group of worms, he says, are the so-called "anecic" worms: the deep soil dwellers. "They live all their life in a single vertical channel in the soil. And at night they surface," looking for food—manure, straw, stuff like that, "and they pull it into their channels."
They're big boys. Which makes them especially vulnerable to the plow. "Because they're so big, so they're chopped, exposed to birds, and their channels are destroyed."
Schmidt and his colleague Maria Briones analyzed the relationship between tilling and the health of a dozen species of earthworms. They looked at 65 years'-worth of farm field studies, spanning the globe.
And they found that in heavily plowed fields, half the earthworms had disappeared. But when farmers switched to no-till or conservation agriculture, worm populations wriggled back to normal numbers after about a decade. The study is in the journal Global Change Biology.
"The plow," Darwin wrote, "is one of the most ancient and most valuable of man's inventions; but long before he existed the land was in fact regularly plowed, and still continues to be thus plowed by earthworms." And, Schmidt says, just as the worms look after the soil, the flip side's true, too. "If you look after the soil, you also look after the earthworms. So it is a good-news story."
Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.
查尔斯·达尔文最著名的身份就是《物种起源》的作者 。但是他写的最后一本书现在却很少人关注 。这本书名为《因蚯蚓活动而产生的腐殖土》 。达尔文非常喜爱蚯蚓：他在书中描写了蚯蚓的习性和土壤耕作能力，他甚至在研究时保留了几盆满是蚯蚓的泥土 。
但他对蚯蚓的痴迷遭到了某些人的嘲笑 。“有一幅著名的漫画，在画中老年达尔文站在中间 。他由猴子进化而来，而猴子则由蚯蚓进化而来 。”
奥拉夫·施密特是都柏林大学的土壤生态学家 。他没有批评达尔文对蚯蚓的兴趣 。“我喜欢蚯蚓，蚯蚓是种神奇的动物 。它们是我们的朋友，而且它们真的非常重要 。”
他认为，其中一群尤为吸引人的蚯蚓是穴居在深层土壤的“深栖类”蚯蚓 。“它们一生都生活在土壤中的一个垂直竖洞里 。它们只在晚上出来活动，”寻找肥料和稻草之类的食物，“然后把食物拖进洞中 。”
它们体型较大 。这使得它们特别容易被耕地的犁伤到 。“因为它们太大了，所以会被斩，并暴露在鸟类面前，它们居住的巢穴也会被毁 。”
施密特和他的同事玛丽亚·布里奥尼斯分析了耕作与12种蚯蚓的健康状况之间的关系 。他们阅览了世界各地长达65年的农田研究 。
他们发现，在耕作量大的农田中，一半的蚯蚓都消失了 。但当农民开始采用免耕法或保护性农业，约10年以后蚯蚓的数量就会“爬”回正常值 。这项研究发表在《全球变化生物学》期刊上 。
达尔文写道，“犁是人类最古老、最有价值的发明之一；但是，早在人类出现以前，蚯蚓就已经在定期耕种土地了，而且蚯蚓还会继续耕种下去 。”施密特表示，就像蚯蚓在照料土壤一样，反之亦然 。“如果你照料了土壤，那你也照料了蚯蚓 。所以这是个好消息 。”
谢谢大家收听科学美国人——60秒科学 。我是克里斯托弗·因塔利亚塔 。
1. meet with 遭到；遇到；获得；
例句：The idea met with a cool response from various quarters.
2. be vulnerable to 易受伤害的；易受影响的；
例句：Young birds are very vulnerable to predators.
3. be exposed to 使暴露于（险境）；使遭受（危险或不快）；
例句：The area where most refugees are waiting is exposed to the elements.
4. look after 照料；照顾；照管；
例句：I love looking after the children.