strive to optimize the system: If a “bad” practice—such
has a dramatic impact on soil biological activity. It
as harvesting in a wet field that contains ripe crops that
encourages the development of earthworm populations,
might spoil if you wait for the soil to dry—is unavoid-
maintains soil moisture, and moderates temperature
able, try to balance it with a “good” practice, thereby
extremes. Compared with conventional tillage, soil ero-
making your soil health account flush.
sion (water, wind, or tillage) is greatly reduced under
If at all possible, use rotations that use grass, legume,
minimum-tillage systems, which help keep organic
or a combination of grass and legume forage crops, or
matter and rich topsoil in place. Any other practices
crops with large amounts of residue as important parts
that reduce soil erosion, such as contour tillage, strip
of the system. Leave residues from annual crops in the
cropping along the contours, and terracing, also help
field, or, if you remove them for feed, composting, or
maintain soil organic matter.
bedding, return them to the soil as manure or compost.
Even if you use minimum-tillage systems, you also
Use cover crops when soils would otherwise be bare to
should use sound crop rotations. In fact, it may be more
add organic matter, capture residual plant nutrients,
important to rotate crops when large amounts of residue
and reduce erosion. Cover crops also help maintain
remain on the surface, as the residue may harbor insect
soil organic matter in resource-scarce regions that lack
Table 23.1
possible substitutes for using crop residues for fuel or
Balance Sheet for Soil Health Management
building materials.
Practice or Condition
Improves
Reduces
Raising animals or having access to animal wastes
Soil Health
Soil Health
from nearby farms gives you a wider choice of economi-
Tillage
cally sound rotations. Those that include perennial for-
moldboard plowing
xx
ages make hay or pasture available for use by dairy and
chisel plowing
x
beef cows, sheep, and goats—and nowadays even poultry.
disking
x
In addition, on mixed crop-livestock farms, animal
harrowing
x
manures can be applied to cropland. It’s easier to main-
no/zone/ridge/strip tillage
x
tain organic matter on a diversified crop-and-livestock
Compaction
farm, where sod crops are fed to animals and manures
light
x
returned to the soil. Compared to crop farms, fewer nutri-
severe
xx
ents leave farms when livestock products are the main
Organic matter additions
economic output. However, growing crops with high
bedded manure
xx
quantities of residues plus frequent use of green manures
liquid manure
x
and composts from vegetative residues helps maintain
compost
xx
soil organic matter and soil health even without animals.
Cover crops
You can maintain or increase soil organic matter
winter grain
xx
more easily when you use reduced-tillage systems, espe-
winter legume
x
cially no-till, strip-till, and zone-till. The decreased soil
summer grain
xx
disturbance keeps biological activity and organic matter
summer legume
xx
decomposition near the surface and helps maintain a
Rotation crops
soil structure that allows rainfall to infiltrate rapidly.
3-year sod
xx
Leaving residue on the surface, or applying mulches,
1-year sod
x
269
Building SoilS for Better CropS: SuStainaBle Soil ManageMent