新英格兰水土流失问题将被妥善解决
文章来源:未知 文章作者:enread 发布时间:2011-01-03 03:41 字体: [ ]  进入论坛
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Erosion is a significant problem on highway embankments(路堤,堤防) in New England. To mitigate1(减轻,缓和) erosion on the regions' highways, slopes are seeded with a grass–legume(豆类) mixture that usually including red fescue(牛毛草) , a grass preferred for its drought-tolerance and ability to thrive in acidic, infertile2 soil. "A mixture of red fescue, perennial3 ryegrass(黑麦草) , and kentucky bluegrass is planted to stabilize4 the soil, but only the red fescue survives long term on slopes", noted5 Rebecca Nelson Brown, lead author of a report in HortScience. Brown and a team from the Department of Plant Sciences at the University of Rhode Island designed a study to identify alternative grass species that could help anchor slopes and prevent costly6 erosion. Twenty-two grass species were included in the study conducted in the greenhouse at the Skogley Turf Research Center of the University of Rhode Island, and in additional roadside trials on the shoulder of a nearby state highway. Since federal highway policy strongly encourages the use of native vegetation in highway right-of-ways, the researchers tested grasses native to southern New England, comparing rooting depth, plant height, and adaptation to roadside conditions. Sixteen native grasses and five amenity7(舒适,礼仪) grasses with red fescue were tested.

Roadside embankments are generally constructed of subsoil and gravel8, over which 2 to 6 inches of topsoil is spread. The subsoils(底土,下层土) are very stony9 with coarse-textured10 loamy sand(壤质沙土) between the rocks; topsoil ranges from medium textured silt11 to sand. Red fescue is shallow-rooted with most of the root mass confined to the topsoil layer. When root growth is concentrated in a shallow mat with a sharp boundary in the soil profile, slope failure is likely to occur beneath the mat. Identifying alternative grasses that feature more even distribution of root mass with depth could help provide better slope stabilization12.

Combined results of the greenhouse and roadside trials showed little bluestem, purple lovegrass, and tall fescue to be the best choices for anchoring roadside slopes. "All species root deeply and are adapted to roadside conditions but are similar in stature13 to red fescue", stated Brown. The researchers found that big bluestem, indiangrass, switchgrass, and bitter panic grass also combine deep rooting with adaptation to roadside conditions, but were significantly taller than red fescue. "These grasses are likely to be too tall for use on mowed14 roadsides. However, to the extent that populations of these species differ in height, selection for deep rooting coupled with reduced topgrowth would be effective in developing cultivars(栽培品种) better suited to roadside use", noted the report.

The authors observed that little bluestem and purple lovegrass are warm-season grasses and dormant15 from October through May, adding that the best way to use these grasses would be as a mix with red fescue and other shallow-rooted cool-season grasses with rapid vegetative spread and minimal16 winter dormancy17(冬眠) . The deep-rooted species would anchor the slope, whereas the rapidly spreading species prevented surface erosion, slowed runoff, and provided the green roadsides desired by the public.

According to the study, an added benefit to using a mix of species is cost-reduction, because seed of little bluestem and purple lovegrass is substantially more expensive than seed of red fescue and other traditional turfgrasses(矮草) and a mix would permit the little bluestem and purple lovegrass to be seeded at reduced rates. "This work should be useful as a guide in choosing grass species to stabilize slopes", the researchers concluded.



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1 mitigate EjRyf     
vt.(使)减轻,(使)缓和
参考例句:
  • The government is trying to mitigate the effects of inflation.政府正试图缓和通货膨胀的影响。
  • Governments should endeavour to mitigate distress.政府应努力缓解贫困问题。
2 infertile u71xE     
adj.不孕的;不肥沃的,贫瘠的
参考例句:
  • Plants can't grow well in the infertile land.在贫瘠的土地上庄稼长不好。
  • Nobody is willing to till this infertile land.这块薄田没有人愿意耕种。
3 perennial i3bz7     
adj.终年的;长久的
参考例句:
  • I wonder at her perennial youthfulness.我对她青春常驻感到惊讶。
  • There's a perennial shortage of teachers with science qualifications.有理科教学资格的老师一直都很短缺。
4 stabilize PvuwZ     
vt.(使)稳定,使稳固,使稳定平衡;vi.稳定
参考例句:
  • They are eager to stabilize currencies.他们急于稳定货币。
  • His blood pressure tended to stabilize.他的血压趋向稳定。
5 noted 5n4zXc     
adj.著名的,知名的
参考例句:
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
6 costly 7zXxh     
adj.昂贵的,价值高的,豪华的
参考例句:
  • It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
  • This dictionary is very useful,only it is a bit costly.这本词典很有用,左不过贵了些。
7 amenity wLuy2     
n.pl.生活福利设施,文娱康乐场所;(不可数)愉快,适意
参考例句:
  • The amenity of his manners won him many friends.他和悦的态度替他赢得很多朋友。
  • Teachers' good amenity and culture have important educational value.教师良好的礼仪修养具有重要的教育价值。
8 gravel s6hyT     
n.砂跞;砂砾层;结石
参考例句:
  • We bought six bags of gravel for the garden path.我们购买了六袋碎石用来铺花园的小路。
  • More gravel is needed to fill the hollow in the drive.需要更多的砾石来填平车道上的坑洼。
9 stony qu1wX     
adj.石头的,多石头的,冷酷的,无情的
参考例句:
  • The ground is too dry and stony.这块地太干,而且布满了石头。
  • He listened to her story with a stony expression.他带着冷漠的表情听她讲经历。
10 textured jgRz7L     
adj.手摸时有感觉的, 有织纹的
参考例句:
  • The shoe's sole had a slightly textured surface. 鞋底表面稍感粗糙。
  • Shallow burial seems to preserve chalky textured porosity. 浅埋藏似能保留具白垩状结构的孔隙。
11 silt tEHyA     
n.淤泥,淤沙,粉砂层,泥沙层;vt.使淤塞;vi.被淤塞
参考例句:
  • The lake was almost solid with silt and vegetation.湖里几乎快被淤泥和植物填满了。
  • During the annual floods the river deposits its silt on the fields.每年河水泛滥时都会在田野上沉积一层淤泥。
12 Stabilization d25ce94d7d536526af8bf72d72ebfb5f     
稳定化
参考例句:
  • The position of barycentre on plane directly impacts the stabilization and manipulation of plane. 飞机重心位置直接影响飞机的稳定和操纵特性。
  • With the higher olefins, stabilization of the energetic intermediates occurs more easily. 在较高的烯烃情况下,高能的中间物稳定作用更易出现。
13 stature ruLw8     
n.(高度)水平,(高度)境界,身高,身材
参考例句:
  • He is five feet five inches in stature.他身高5英尺5英寸。
  • The dress models are tall of stature.时装模特儿的身材都较高。
14 mowed 19a6e054ba8c2bc553dcc339ac433294     
v.刈,割( mow的过去式和过去分词 )
参考例句:
  • The enemy were mowed down with machine-gun fire. 敌人被机枪的火力扫倒。 来自《现代英汉综合大词典》
  • Men mowed the wide lawns and seeded them. 人们割了大片草地的草,然后在上面播种。 来自辞典例句
15 dormant d8uyk     
adj.暂停活动的;休眠的;潜伏的
参考例句:
  • Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。
  • This dormant volcano suddenly fired up.这座休眠火山突然爆发了。
16 minimal ODjx6     
adj.尽可能少的,最小的
参考例句:
  • They referred to this kind of art as minimal art.他们把这种艺术叫微型艺术。
  • I stayed with friends, so my expenses were minimal.我住在朋友家,所以我的花费很小。
17 dormancy 9c7eb5512211f4cd18877be97c85655b     
n.睡眠,冬眠,隐匿
参考例句:
  • During dormancy the plants must be kept very dry. 在休眠期,植物必须保持非常干燥。 来自辞典例句
  • It may also come to the point of virtual dormancy. 它也可以达到实际上的潜伏状态。 来自辞典例句
TAG标签: soil highway erosion
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