But terraces are narrow and their retaining banks thin, and because they're so easily broken by peasants tramping across them to work the land, they can't function effectively to block runoff.
但由於等高線間差距小、駁坎淺，農民在栽培過程中，不免於各階駁坎間來回踩踏，駁坎不久便毀損而失去阻斷逕流的作用。