suburban lot. In 1987, when I was in the market for a new homestead,
I first went to my county SCS office, mapped out locations where the
soil was suitable, and then went hunting. Most counties have their
own office.

Using Humus to Increase Soil Moisture

Maintaining topsoil humus content in the 4 to 5 percent range is
vital to plant health, vital to growing more nutritious food, and
essential to bringing the soil into that state of easy workability
and cooperation known as good tilth. Humus is a spongy substance
capable of holding several times more available moisture than clay.
There are also new synthetic, long-lasting soil amendments that hold
and release even more moisture than humus. Garden books frequently
recommend tilling in extraordinarily large amounts of organic matter
to increase a soil's water-holding capacity in the top few inches.

Humus can improve many aspects of soil but will not reduce a
garden's overall need for irrigation, because it is simply not
practical to maintain sufficient humus deeply enough. Rotary tilling
only blends amendments into the top 6 or 7 inches of soil. Rigorous
double digging by actually trenching out 12 inches and then spading
up the next foot theoretically allows one to mix in significant
amounts of organic matter to nearly 24 inches. But plants can use
water from far deeper than that. Let's realistically consider how
much soil moisture reserves might be increased by double digging and
incorporating large quantities of organic matter.

A healthy topsoil organic matter level in our climate is about 4
percent. This rapidly declines to less than 0.5 percent in the