3 THE HANDLING OF THE LAND 91 
In small garden areas, this deep preparation will ordinarily 
be done by trenching with a spade. This operation of trench- 
ing consists in breaking up the earth two spades deep. Figure 81 
explains the operation. The section at the left shows a single 
spading, the earth being thrown over to the right, leaving the 
subsoil exposed the whole width of the bed. The section at 
the right shows a similar operation, so far as the surface spading 
is concerned, but the subsoil has also been cut as fast as it has 
been exposed. This under soil is not thrown out on the surface, 
82. Home-made subsoil plow. 
and usually it is not inverted; but a spadeful is lifted and then 
allowed to drop so that it is thoroughly broken and pulverized 
in the manipulation. 
In all lands that have a hard and high subsoil, it is usually 
essential to practice trenching if the best results are to be 
secured; this is especially true when deep-rooted plants, as 
beets, parsnips, and other root-crops, are to be grown; it pre- 
pares the soil to hold moisture; and it allows the water of heavy 
rainfall to pass to greater depths rather than to be held as 
puddles and in mud on the surface. 
In places that can be entered with a team, deep and heavy 
plowing to the depth of seven to ten inches may be desirable 
on hard lands, especially if such lands cannot be plowed very 
