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
外语
Low-level slash-and-burn farming doesn’t harm rainforest. On the contrary, it helps farmers and improves forest soils. This is t
Low-level slash-and-burn farming doesn’t harm rainforest. On the contrary, it helps farmers and improves forest soils. This is t
admin
2014-01-13
46
问题
Low-level slash-and-burn 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(烧成炭的)wood left over from thousands of years of slash-and-burn faring." 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(粪肥)." 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
根据文章最后两句“Glaser claims that these earth works,built between AD 400 and1 400,were at the heart of urban civilizations.Now it seems the richness of the Terra Preta soilsmay explain how such civilizations managed to feed themselves.”可知,格拉瑟声称,这些制造于公元前400年和公元1400年之间的陶瓷作品位于城市文明的中心。现在,这些富饶的TerraPreta土壤也许可以解释这些文明是如何发生发展的。据此判断,答案是D。
转载请注明原文地址:https://kaotiyun.com/show/PKhO777K
0
考博英语
相关试题推荐
Everysecond,【C1】______hectareoftheworld’srainforestisdestroyed.That’sonetotwofootballfields.This【C2】______rate
Hurricanesareviolentstormsthatcausemillionsofdollarsinpropertydamageandtakemanylives.Theycanbeextremelydange
Youshouldspendnomorethan20minutesonthistask.Youandyourfamilyhaddinnerinarestaurantafewnightsago.The
Since1000A.D.,around30billionpeoplehavebeenbrnonourplanet.Thevastmajorityhavecomeandgoneunknowntoallbutt
Consumersandproducersobviouslymakedecisionsthatmoldtheeconomy,butthereisathirdmajor【61】toconsidertheroleofg
Consumersandproducersobviouslymakedecisionsthatmoldtheeconomy,butthereisathirdmajor【61】toconsidertheroleofg
St.Paulhastransformedsoaringenergycostsintoagoldenopportunityforeconomicdevelopmentbyputtingthefinaltoucheson
Whatissodepressingaboutthiswaristhe______hatredthatbothsidesfeelforeachother.
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisortofindthegiftedfewan
Thefistsentenceinthisparagraphis______;itcanbeinterpretedinmanyways.
随机试题
患儿,男性,10岁,因血尿、浮肿、少尿收入院,初步诊断为急性肾小球肾炎。需作什么检查
多系统器官衰竭是指()
下列关于颈椎的描述,错误的是()
测定中心静脉压时,测压的玻璃管的零点应在()。
美国糖尿病学会推荐糖尿病治疗中控制好的标准为
可用于心悸、失眠、多梦的药物是
世界卫生组织为了达到"2000年人人享有卫生保健"所采取的基本措施是
某项目主力户型以三居室为主,对于本区域而言面积偏大,这一条件在SWOT矩阵中应以()为条件。
2016年,广东民营经济增加值突破四万亿元。经初步核算,全年实现民营经济增加值42578.76亿元,按可比价计算,比上年同期增长7.8%,增幅高于同期GDP增幅0.3个百分点.其中第二产业增幅比同期GDP第二产业增幅高3个百分点。民营经济占GDP的比重为5
关于实践活动及其作用,下述观点正确的有
最新回复
(
0
)