当表层土流失后，就只剩下一片无用的沙漠。

When all the topsoil is gone, nothing remains but a worthless desert.

本实验采用土柱通风法模拟SVE，对氯化苦在表层土中的迁移过程和去除效果进行了分析。

Some of the commonly used soil fumigants also have high volatilization, which makes it possible to remove fumigants from topsoil by SVE.

理想的土壤应该是表层土贫瘠，而里层土能有效保留水分，排水性好以确保葡萄树跟不会过于饱和的土壤。

The ideal circumstance for a vine is an area of thin topsoil and subsoil that sufficiently retains waters but also has good drainage so that the vine roots don't become overly saturated.

很多农民采用较好的保护土地的措施，并且爱荷华州广袤而丰饶的表层土的深度足以持续数十年适度的大量土地侵蚀。

Many farmers use good conservation practices, and the state’s rich topsoil in many areas is deep enough to last decades with moderate amounts of erosion.

而将机器送上月球，既可以加热表层土，又可以用来建造建筑和产生能源，这至少是一件棘手的事情。

And getting machines to the moon that could heat up that regolith, as well as ones to construct buildings and generate energy, would be tricky to say the least.