VOA慢速英语:Getting a Firm Grip on Weed Control

This is the VOA Special English Agriculture Report.
这里是美国之音慢速英语农业报道。
 
When is a plant considered a weed? Experts at Penn State University have a simple answer: When the undesirable qualities outweigh the good qualities.
植物在什么时候被当做杂草？宾夕法尼亚州立大学的专家们给了简单的答案，那就是当不合意的品质大于良好品质时。

 
Consider the fact that crops generally produce several hundred seeds from each plant. By comparison, each weed plant can produce tens or even hundreds of thousands of seeds. And some buried seeds can survive up to forty years -- or even longer.
通常情况下，农作物每株会生产几百粒种子。但是每株野草会生产几万甚至几十万粒种子。有一些深埋的种子可以存活四十年甚至更长时间。
 
Eradicating weeds means that you have to remove all the seeds and roots so the plants will not grow back. But birds or the wind can reintroduce them to the land.
根除野草意味着必须除掉所有的种子，并且将植株连根拔起，以免其重生。但是鸟或风会将种子重新带回土地。
 
A more common way to deal with weeds is to control them enough so that the land can be used for planting. Experts advise using two or more control methods to deal with weeds.
处理野草更加普遍的方法是对其加以中分的控制，使土地可以耕种。专家建议使用两种或者更多方法来处理野草。

Chemical weed killers or natural treatments like corn gluten can suppress weed growth. Dense planting of a crop can also act as a natural control.
化学杀虫剂或玉米黄粉等自然方法可抑制杂草生长，将作物种稠密些也可自然控制杂草。

Bill Curran is a professor of weed science at Penn State, in University Park, Pennsylvania. He says one of the most common methods for suppressing weeds is dense planting.
Bill Curran是宾夕法尼亚州立大学大学城分校教授，他说最常见的控制杂草的办法是密植。

He says a dense, competitive crop that quickly shades the soil will help suppress many weeds. The seeds need light to grow, so blocking the sun will reduce weed growth.
他说，稠密、竞争性强的作物可以快速遮盖土壤并抑制多种杂草，种子生长需要阳光，所以封锁阳光就阻止杂草的生长。
 
Other controls include turning over the soil, pulling the weeds or covering them with mulch made of shredded wood, garden waste or other material.
其他控制方法包括翻土，用手拔草或者用木质地膜，花园废弃物或其他材料进行覆盖。

But even mulch has its limits. Natural resource specialists point out that weeds can be transported in mulch. This is also true of soil, grain, hay and animals.
但是覆盖物也有其局限性。自然资源专家指出，杂草可以通过地膜进行传播。也可以通过土壤，谷物，干草和动物进行传播。

Yet animals like sheep or goats eat weeds, so they can provide a biological control. Insects and other organisms can also act as biological controls.
然而，动物，比如绵羊或山羊可以起到生物控制的作用——他们会吃掉杂草。昆虫和其他有机体都可以起到生物控制的作用。

Preventing the spread of weeds is an important part of weed management. Farm vehicles should be kept out of areas with weeds. If that is not possible, then clean off the equipment and your shoes when leaving.
控制杂草的传播是杂草管理的重要部分。农田机器应该远离长满杂草的地方。如果不可能的话，离开的时候要清洁机器和鞋子。

Some people burn weeds or bury them deeply or make them into mulch.
一些人将杂草和花园废弃物带到垃圾中心或者燃烧，深埋或将他们绞碎。

Professor Curran says another way to make use of weeds is to compost them. Heat is produced in the process of making organically rich compost to improve soil. The heat will kill many, though not all, weed seeds. The same is true for seeds that pass through animals that graze on weeds.
Curran教授说，用杂草制作堆制肥料是对杂草加以利用的好方法。制作有机堆肥的过程会产生热量。热量会杀死许多杂草种子。农田生物拒绝杂草的过程道理也是一样的。