首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Low-level slash-and-bum farming doesn’t harm rainforest. On the contrary, it helps farmers and improves forest soils. This is th
Low-level slash-and-bum farming doesn’t harm rainforest. On the contrary, it helps farmers and improves forest soils. This is th
admin
2012-01-05
32
问题
Low-level slash-and-bum farming doesn’t harm rainforest. On the contrary, it helps farmers and improves forest soils. This is the unorthodox view of a German soil scientist who has shown that burnt clearings in the Amazon, dating back more than 1,000 years, helped create patches of rich, fertile soil that farmers still benefit from today.
Most rainforest soils are thin and poor because they lack minerals and because the heat and heavy rainfall destroy most organic matter in the soils within four years of it reaching the forest floor. This means topsoil contains few of the ingredients needed for long-term successful farming.
But Bruno Glaser, a soil scientist of the University of Bayreuth, has studied unexpected patches of fertile soils in the central Amazon. These soils contain lots of organic matter.
Glaser has shown that most of this fertile organic matter comes from " black carbon"—the organic particles from camp fires and charred wood left over from thousands of years of slash-and-bum farming." The soils, known as Terra Preta, contained up to 70 times more black carbon than the surrounding soil," says Glaser.
Unburnt vegetation rots quickly, but black carbon persists in the soil for many centuries. Radiocarbon dating shows that the charred wood in Terra Preta soils is typically more than 1,000 years old.
"Slash-and-burn farming can be good for soils provided it doesn’t completely burn all the vegetation, and leaves behind charred wood," says Glaser. "It can be better than manure." Burning the forest just once can leave behind enough black carbon to keep the soil fertile for thousands of years. And rainforests easily regrow after small- scale clearing. Contrary to the conventional view that human activities damage the environment, Glaser says: "Black carbon combined with human wastes is responsible for the richness of Terra Preta soils."
Terra Preta soils turn up in large patches all over the Amazon, where they are highly prized by farmers. All the patches fall within 500 square kilometers in the central Amazon. Glaser says the widespread presence of pottery confirms the soil’s human origins.
The findings add weight to the theory that large areas of the Amazon have recovered so well from past periods of agricultural use that the regrowth has been mistaken by generations of biologists for "virgin" forest.
During the past decade, researchers have discovered hundreds of large earth works deep in the jungle. They are up to 20 meters high and cover up to a square kilometer. Glaser claims that these earth works, built between AD 400 and 1400, were at the heart of urban civilizations. Now it seems the richness of the Terra Preta soils may explain how such civilizations managed to feed themselves.
From the passage it can be inferred that ______.
选项
A、human activities will do grave damage to rainforests
B、Amazon rainforest soils used to be the richest in the world
C、farming is responsible for the destruction of the Amazon rainforests
D、there once existed an urban civilization in the Amazon rainforests
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/mAua777K
本试题收录于:
翻译硕士(翻译硕士英语)题库专业硕士分类
0
翻译硕士(翻译硕士英语)
专业硕士
相关试题推荐
InEnglandintheearly17thcentury,theStuartmonarchy,tofinanceitsexpenditures,increasinglyresortedto"forcedloans"—
translationquality
rawmaterials
TheSupremeCourt’sdecisionsonphysician-assistedsuicidecarryimportant______forhowmedicineseekstorelievedyingpatie
IndigenousAustraliansbelievethatreconciliationisnecessarybutthegovernmentshould,mostimportantly,makeaformalapolo
TheonepleasurethatEinstein______hisgreatfamewastheabilityitgavehimtohelpothers.
Low-levelslash-and-bumfarmingdoesn’tharmrainforest.Onthecontrary,ithelpsfarmersandimprovesforestsoils.Thisisth
ContrarytothepredictionsofsomecommentatorsofareturntoaHobbesianworld,theendoftheColdWarhasnotbeenaccompan
Aforestfirewillleavenothingbutscorchedearthinitswake.
Whyhasmiseducationbecomeasocietalnorm?(ThisquestionisbasedonPassage5)
随机试题
二陈汤的功效是
异烟肼中游离肼检查时,应
患者,女,23岁,月经漏下已经1个月余,经血质稀,色淡红,劳累则出血加重,舌质淡白,脉细弱,其出血原因是()
患者,男性,1岁半。平日偏食,常有腹泻、咳嗽,已会独立行走,玩耍正常。近2个月来面色苍黄,逗之不笑,时有头部、肢体颤抖,不能独站。外周血象:血红蛋白100g/L,红细胞2.5×109/L,白细胞4×109/L,中性粒细胞分叶过多。本例可诊断为
海外领队是经过国家旅游行政主管部门批准组织出境旅游的旅行社的代表,是出境旅游团的领导者和代言人,其主要职责是()。
下列说法正确的是:
假设消费者收入增加25%,会导致某种商品的需求量增加10%,则该商品的类型为()。
(94年)若f(x)=在(-∞,+∞)上连续,则a=_________.
Itisratherimportantforafarmerandanairplanepilottoknow【T1】______theweatherwillbelike.Unlesstheyknowwhatweat
Commercialaquaculturecanbea【B1】______andenvironmentallysustainableactivityifconductedwiththerightmethodsintherig
最新回复
(
0
)