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(单词翻译)
This is the VOA Special English Agriculture Report.
Farmers and gardeners have turned the soil for centuries. But many now believe in no-till or reduced tillage, a method also called conservation tillage. The Conservation Technology Information Center says forty percent of American cropland used this method at last report.
Tilling can remove weeds and the waste from last season's crops and help break down old plant material into fertilizer. But it can also increase the risk of soil erosion by rain or wind.
Tilling also releases carbon dioxide from the soil into the atmosphere. No-till keeps carbon in the soil and avoids the release of heat-trapping gases from motorized equipment. It also keeps water in the soil and protects helpful organisms like earthworms. And it saves money on labor1, machinery2 and fuel.
A recent study reported on almost twenty years of different tillage methods in the American states of Colorado, Kansas and Nebraska.
The researchers say tillage makes soil less resistant3 to being broken apart by raindrops than plowed4 soil. They say no-till stores more soil carbon, which helps the soil particles stick together. They found that the first two and a half centimeters of topsoil are up to seven times stronger against rain than plowed soil.
A farmer tilling a field near Hastings, Minnesota in April
The study also noted5 that when tilled soil particles come in contact with air, soil organic matter is lost through the process of oxidation.
The findings appeared in the Soil Science Society of America Journal. Humberto Blanco-Canqui from Kansas State University and Maysoon Mikha from the Agricultural Research Service led the study.
Another recent study found that a single tillage does not harm yield or soil structure in land that is normally not tilled. Charles Wortmann at the University of Nebraska-Lincoln says a one-time tillage may be used to correct a problem like aggressive weeds. His five-year study appeared in the Agronomy6 Journal.
Fabian Fernandez, a soil and plant nutrition expert at the University of Illinois, says no-till means less intensive labor. But he also says it does not mean an end to preparing the ground for planting.
Jimmy Wagner works at the American Plant garden center in Bethesda, Maryland. He says hand tools like tilling forks, shovels7 and thatching rakes require more work than a rotary8 tiller, but they work well and cost less.
If you till, wait until the soil is warm and dry enough. If the soil stays together in a ball, it is too wet to till.
And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I'm Jim Tedder9.
1 labor | |
n.劳动,努力,工作,劳工;分娩;vi.劳动,努力,苦干;vt.详细分析;麻烦 | |
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2 machinery | |
n.(总称)机械,机器;机构 | |
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3 resistant | |
adj.(to)抵抗的,有抵抗力的 | |
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4 plowed | |
v.耕( plow的过去式和过去分词 );犁耕;费力穿过 | |
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5 noted | |
adj.著名的,知名的 | |
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6 agronomy | |
n.农业经济学 | |
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7 shovels | |
n.铲子( shovel的名词复数 );锹;推土机、挖土机等的)铲;铲形部份v.铲子( shovel的第三人称单数 );锹;推土机、挖土机等的)铲;铲形部份 | |
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8 rotary | |
adj.(运动等)旋转的;轮转的;转动的 | |
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9 tedder | |
n.(干草)翻晒者,翻晒机 | |
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