《北史·列传·卷八十二》
田地肥沃，先用火烧，然后引水灌溉，拿一个插子，用石头做刀刃，长一尺多，宽数寸，来开垦土地。
厥田良沃，先以火烧，而引水灌，持一锸，以石为刃，长尺余，阔数寸，而垦之。
The land is fertile, they first burn it with fire, then irrigate it with water, take a stick, use a stone as the blade, more than a foot long, several inches wide, to cultivate the land.