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

嚴格控制雜草

This is the VOA Special English Agriculture Report.

這里是美國之音慢速英語農(nóng)業(yè)報道。

When is a plant considered a weed? Experts at Penn State University have a simple answer: When the undesirable qualities outweigh the good qualities.

什么時候植物會被當成雜草?賓夕法尼亞州立大學的專家們給出了一個簡單的答案：當其不良品質(zhì)超過優(yōu)良品質(zhì)時。

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.

考慮到每株農(nóng)作物通常產(chǎn)生幾百顆種子。而相比之下，每株雜草能產(chǎn)生數(shù)萬甚至數(shù)十萬顆種子。而且，一些被埋在地里的種子可以存活40年乃至更久。

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.

要根除雜草意味著你必須除掉所有的種子和根系，這樣雜草才不會再次長出來。但是，鳥類或風會將它們重新帶到地里。

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.

對雜草更為常見的處理方式是適度控制，這樣土地就能用于種植。專家們建議使用兩種或兩種以上的方法控制雜草。

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.

化學除草劑或類似玉米麩等自然手段可以抑制雜草的生長。作物密集種植也能作為一種自然控制手段。

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.

賓夕法尼亞州立大學大學城分校的比爾·柯倫(Bill Curran)是一位雜草學教授。他說，密植是抑制雜草最常用的方法之一。

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.

他說，經(jīng)過密植的具有競爭力的作物會很快遮蔽土地，這將有助于抑制雜草生長。雜草生長需要陽光，所以遮蔽陽光能夠減少雜草生長。

Other controls include turning over the soil, pulling the weeds or covering them with mulch made of shredded wood, garden waste or other material.

其他手段還包括翻土，拔除雜草或用地膜覆蓋它們。地膜一般由木屑、花園廢棄物或其他材料制成。

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，地膜也有其局限性。自然資源專家指出，雜草可以在地膜里傳播，還可以通過土壤，谷物，干草和動物傳播。

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，像綿羊或山羊之類的動物吃雜草，因此它們可以起到生物控制作用。昆蟲和其他生物也可以起到生物控制作用。

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.

控制雜草傳播是雜草管理中的一個重要環(huán)節(jié)。農(nóng)用機械應該遠離雜草，如果無法做到，在離開雜草區(qū)域時清理干凈農(nóng)用機械和你的鞋子。

Some people burn weeds or bury them deeply or make them into mulch.

有些人會將雜草燒掉或深埋，或?qū)⑺鼈冏優(yōu)榈啬ぁ?/p>

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.

柯倫教授說，另一種方式是將雜草制成堆肥。制造有機堆肥的過程會產(chǎn)生熱量，這些熱量會殺死絕大部分雜草種子。將雜草喂食動物通過動物消化的結(jié)果也是如此。