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Cover Crop Benefits
Here's
the laundry list of benefits cover crops will bring to your garden:
Prevent erosion. Cover crops' roots help
stabilize garden soil, prevent runoff, and ensure that your rich soil stays put.
Add organic matter. Both roots and topgrowth
contribute organic matter to the soil after they are tilled under. "A
combination of cover crops and compost is an excellent choice for building
long-term organic matter and providing sufficient seasonal nutrients to the
garden," says Dr. Sarrantonio.
Increase microorganisms. Organic matter and
the roots of growing cover crops stimulate microorganisms, which help suppress
disease organisms, improve soil structure, and digest organic matter so that
nutrients can be used by plants. Steve Diver recommends inoculating cover crops
with compost tea before tilling them under, because it helps them decompose
faster.
Stabilize and add nutrients. Cover crops
cover the soil and prevent excess nitrogen from leaching. Plants take up excess
soil nitrogen and return it to the soil when they are turned under. In addition,
legumes, such as clover, fix atmospheric nitrogen in special nodules on their
roots, in collaboration with Rhizobium bacteria. This nitrogen can be
used by the next crop you grow. In this way, cover crops act as a bank account
for nutrients, returning the investment with interest when you turn them under.
Help control pests and diseases. "Cover
crops add organic matter, which feeds the microbes that can play important roles
in the garden like disease suppression," says Dr. Creamer. Cover crops also
encourage beneficial insects by providing flowers for a nectar source and
foliage for shelter.
Suppress weeds. This is the one I like—less
weeding! Some cover crops, such as buckwheat, grow so densely that they
outcompete weeds—that's why they are sometimes called smother crops.
Others, like rye, oats, and sorghum-sudangrass (I call them the cover-crop
"bad boys") have an allelopathic effect on weeds—they actually exude
compounds that suppress the germination of weed seeds. Because these compounds
can last awhile in the soil, it's important to wait three weeks after tilling
them under to plant your garden.
