“We’ll have a sample a day,year round so that really pins down what the chemistry is like,” says Dave Baker of Ohio’s Heidelberg University,who took charge of the monitoring stations for the Department of Natural Resources.
The U.S.Environmental Protection Agency,the federal government’s pollution watchdog,requires point sources,such as factories,to monitor and report their discharges(排出物).So Baker is looking for where the other sources of pollution come from.
“If there are problems in Lake Erie,we want to know where it’s coming from and make sure we’re putting resources to solve the problem properly,” Baker says.“It’s stations like this that help do that.”
In this case,a primary source of the pollution turns out to be chemical fertilizers that wash off farmland during rainstorms.
Because farmers and ranchers believe fertilizers are essential to high crop yields,they would like to use them.However,the USDA’s Natural Resource Conservation Service isn’t asking them to abandon farm chemicals,but rather to use them more sparingly(慎用地) so that they don’t run off the land when it rains.
Another technique for reducing farm chemical pollution of Lake Erie is covercrop farming.After the harvest,farmers plant a second quickgrowing crop to reduce erosion.The deeprooted plants,such as rye or turnips,help to cover the soil,allowing worms and fungi to work their magic and helping the soil to absorb more water and nutrients.
【【加练半小时】2017届高考英语一轮复习训练:第52练(含解析)】相关文章:
★ 【加练半小时】2017届高考英语一轮复习训练:第66练(含解析)
★ 【优化方案】2017届高考英语二轮复习全国卷Ⅱ题型重组训练:第4组(含解析)
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21