Mangroves are the most readily available source of firewood for fires to boil seawater and what is called "salt dust" scraped from the soil.

VOA: standard.2010.03.29

In Democracy in America there's that famous passage, or passages, when Tocqueville crosses the Ohio River, from Ohio into Kentucky, from free soil into slave soil, free state into a slave state.

在托克维尔跨越俄亥俄河,从俄亥俄进入到肯塔基州,从自由之所走向奴役之地的那段游历中,为《美国民主》贡献了数段名言

耶鲁公开课 - 美国内战与重建课程节选

He says a dense, competitive crop that quickly shades the soil from the sun will help reduce weed growth.

VOA: special.2011.07.26

David Robson from the University of Illinois Extension says the best results come from moist, richly organic black soil.

VOA: special.2009.07.07

The volunteers placed the plants about five centimeters into the soil to prevent rising and falling water levels from pulling them out.

VOA: special.2009.10.06

He says there is likely more risk from lead dust on plants or from playing in the soil than from the plant itself.

VOA: special.2009.06.09

No-till keeps carbon in the soil and avoids the release of heat-trapping gases from motorized equipment.

VOA: special.2010.09.28

It helps keep the soil from getting dry, so it reduces the need for watering.

VOA: special.2009.06.30

As the mulch breaks down, it provides material that keeps the soil from getting hard.

VOA: special.2009.06.30

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

VOA: special.2009.05.26

Researchers from the African Soil Information Service will study earth samples and rate them.

VOA: special.2009.01.20

It prevents the humidity in the soil from evaporating.

VOA: special.2010.07.13

Authorities here have acknowledged that deforestation and unregulated development were responsible for weakening the soil and contributed to the mudslides from Messina's surrounding hills and cliffs.

VOA: standard.2009.10.03

he said,"The presence of PKK forces on Iraqi soil has harmed villagers from over 500 Kurdish town and the PKK must either lay down its arms or leave Iraq."

VOA: standard.2009.03.23