The summer fallow with repeated ploughing was its basis.
Using these buoys to guide the direction of tow, a grapnel, a species of fivepronged anchor, attached to a strong compound rope formed of strands of steel and manila, is lowered to the bottom and dragged at a slow speed, as it were ploughing a furrow in the sea bottom, in a line at right angles to the cable route, until the behaviour of the dynamometer shows that the cable is hooked.
The autumnal subsidence of the river was followed by shallow ploughing performed by oxen yoked to clumsy wooden ploughs, the clods being afterwards levelled with wooden hoes by hand.
Oxen are used for ploughing the higher lands with light soil, and the heavier and stronger buffaloes for ploughing wet tracts and marshy lands.
The ploughing begins in October, and continues a month or six weeks, according to the season.
