sù / liào / bó / mó / bèi / fù / zài / tǔ / rǎng / biǎo / miàn / kě / yǐ / bǎo / chí / shuǐ / fèn塑料薄膜被覆在土壤表面,可以保持水分Plastic film covering the soil surface can retain moisture.