cover crop resources

Jack Rowe jackrowe at compuserve.com
Thu Aug 28 15:44:00 EDT 1997


Mike Skinner, easyhay at arn.net, asked:
“What kind of legume specifically would you recommend for the Texas
panhandle where I live? On dryland, particularily. The conflict I see is
between water conservation and fertilizer/tilth improvement. This area
receives between 15 to 25 inches in various sized events and temperatures
usually 10 to 15 below in winter and 100 degrees in the summer. Not to
mention the wind of 45 mph. Challenging!”

Soil testing is a good starting idea, many legumes will not fix N
effectively without good Phosphorous and trace minerals. In dry areas, a
plant’s drought-tolerating strategies are cogent... mesquite and alfalfa
both grow in drought, but do so by sending deep roots after subsurface
water and can make subsequent crops suffer by drying deep soils, for
instance (mesquites indicate subsurface water within about 50 feet).
Swaling, and on-contour furrowing between swales, are especially-useful in
dry climates. Don’t forget trees when using swales.

Some commonly-available cover crops good on a variety of soils include:
Oats (Avena sativa) 
Tall Fescue (Festuca aruninacea)
Black Medic (Medicago lupulina) -- n-fixing
Alfalfa (Medicago sativa) -- n-fixing, drought-hardy
Sweet clovers (Melilotus alba, White, and M. officinalis, Yellow) --
n-fixing
Annual Ryegrass (Secale spp)
Redtop (Agrostis alba)
Rose Clover (Trifolium hirtum) -- n-fixing
Vetches (Vicia spp) and Vetchlings (Lathyrus spp) use 15 - 20 inches of
water
Sorghums (Sorghum bicolor) heat- and drought-tolerant

The medicagos as a group are pretty impressive; the fava and bell beans are
good in sandy soils in winter; Prairie clovers (Petalasemum spp --
spelling?) can be very successful in rainfalls as low as 14 inches; vetches
are very cold-hardy (favas are a Vicia); the winter grasses create large
dry biomass, capture excess N and K left at the end of the season and
operate during a commonly-unused time of year; mung beans, radishes and
buckwheat are extremely-rapid growers and can be ready to mow or
incorporate in as few as 35 days; redtop and sorghums are amazing in heat
and drought; cowpeas will produce a lot of green matter with
relatively-little water; mustard is cold-hardy and will collect calcium (if
it’s there)...

Best is to know your soil and find a number of learning resources to
combine... my favorites:

ATTRA (Appropriate Tech Transfer for Rural Areas -- heaven help us if the
Republicans have finally gotten this one -- we really need a Democrat in
the White House about now!). ATTRA will send you the best single packet
about cover crops that I know of, as well as on a broad variety of other
subjects. These guys are GREAT!
PO Box 3657
Fayetteville, AR  72702
800-346-9140

County Extension Agents -- I know, I know, but if you listen carefully and
translate you can glean a lot of actually-useful information. Don’t follow
their advice and dump an entire season’s highly-soluble nitrate fertilizer
on your soil at the start of the year (hmmm...), but soil testing is cheap
and can be used as a reference point, and they will lead you to the
conventional cover crop sources which perform in your area. Ditto the local
farmer’s co-op/feed store. 

Library -- lots of good books, often the somewhat older ones are best.

Great Outdoors -- lots of hints here... look in drainage ditches and weedy
areas to see which plants have done well enough to have escaped, etc.



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