VOA慢速英语 2007 0306a

This is the VOA Special English Agriculture Report.

To call something marginal¹ means it is not very good. Farmers have their own way to define² marginal land: It is the last to be planted under good conditions, and the first to be avoided under poor conditions.

Low quality soil is not the only reason land could be considered marginal. It might be in an area where rainfall is limited. Or a hillside might rise too steeply.

There are uses for marginal land, however. Most often it is used as grassland³. Grasses provide excellent feed for grazing⁴ animals like cattle, sheep and goats.

Grass seed can be bought from a supplier. Or native grasses can be used. But it is important to establish good ground cover to avoid soil loss through erosion⁵.

Forage⁶ crops like clover and alfalfa can be planted. These members of the legume family provide high protein food for grazing animals. They also improve the quality of the soil.

Most plants use up nitrogen. But legumes put nitrogen back into the soil. Forage crops also help limit erosion.

However, using marginal land for grazing is not a simple issue. There is a risk of overgrazing. Cattle can damage forage crops by eating down to the roots. Also, the weight of the animals crushes the soil and can make it too hard for growing.

A way to reduce the harm is to move animals from one field to another. This method is known as rotational⁷ grazing. Experts say rotational grazing is extremely important for marginal land.

Another use for marginal land is for tree crops. Studies have shown that the white pine and loblolly pine are two kinds of trees that grow well on such land. They grow fast and provide good quality wood. Another tree is the poplar, found in many parts of the world. Slower-growing trees like the black walnut⁸ also provide a nut crop.

Trees support the soil. They reduce the effects of wind and rain. And they help block the sun.

Failure to take the care needed to protect marginal lands can make a bad situation worse. But good planning can turn a marginal resource into a highly productive⁹ one.

This VOA Special English Agriculture Report was written by Mario Ritter. Our reports are online at www.unsv.com. If you have a question about agriculture, send it to [email protected]. We might answer it on our program. I'm Barbara Klein.

1 marginal   

adj.微小的，仅以微弱多数获胜的，有旁注的

参考例句：

• He won the most marginal seat by only two votes.他只以两票的微弱优势当选。
• This once important social group is becoming more and more marginal.这个一度十分重要的社会集团越来越无足轻重了。

2 define   

vt.解释，下定义，阐述，限定，规定

参考例句：

• Please define the words.请解释这些字的意义。
• It's hard to define exactly what has changed.很难解释清楚到底发生了什么变化。

3 grassland   

n.牧场，草地，草原

参考例句：

• There is a reach of grassland in the distance.远处是连绵一片的草原。
• The snowstorm swept the vast expanse of grassland.暴风雪袭击了辽阔的草原。

4 grazing   

n. 放牧, 牧草 动词graze的现在分词

参考例句：

• There were cows grazing beside the river. 有些牛在河边吃草。
• Cows were grazing on the marshes. 牛群在湿地上吃草。

5 erosion   

n.腐蚀，侵蚀，磨损，削弱，减少

参考例句：

• The erosion of beach here is serious.这里海岸的腐蚀很严重。
• Drought and soil erosion had long been a major problem.干旱和水土流失一直是个老大难问题。

6 forage   

n.(牛马的)饲料，粮草；v.搜寻，翻寻

参考例句：

• They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
• Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。

7 rotational   

adj.回转的，轮流的

参考例句：

• A synchronous motor drives the measuring bob at a constant rotational speed.同步马达驱动测锤以恒速旋转。
• With some limitations,this is true also of rotational degrees of freedom.在某些限定条件下，这一说法对转动自由度也成立。

8 walnut   

n.胡桃，胡桃木，胡桃色，茶色

参考例句：

• Walnut is a local specialty here.核桃是此地的土特产。
• The stool comes in several sizes in walnut or mahogany.凳子有几种尺寸，材质分胡桃木和红木两种。

9 productive   

adj.能生产的，有生产价值的，多产的

参考例句：

• We had a productive meeting that solved some problems.我们开了一个富有成效的会议，解决了一些问题。
• Science and technology are part of the productive forces.科学技术是生产力。