permaculture

[Mark Ludwig <mpludwig@students.wisc.edu>]

At 09:58 AM 1/31/97 -0500, you wrote:
>Just one point on this excellent discussion:
>
>Because N is lost if not taken up when available, and lost as water
>pollution, we need a mix of species that function during as much of the year
>as possible.  In my observation, the most complete system is the native
>prairie, which is not merely a spatial mosaic of plants, but a temporal
>mosaic, with plants occupying almost the same space but putting on growth at
>different seasons. 

Mark, light weight prairie ecologist, says...
A major factor in the prairie system is the mix of C-3 (3 carbon
photosynthesis, or cool season) and C-4 (4 carbon, warm season) grasses and
forbs.  The C-4's are typically bunch grasses and take more time and care to
establish than the C-3's.  The growth curve of the C-4's almost perfectly
compliments the dip the c-3's take in mid summer.  The real tricky part in a
grazing system is growing these plants together.  In general the
recomendations I get are to grow C-4's alone or with a single legume
species.  In native prairies in the upper midwest we do get some cool season
native grasses that do well with the C-4's, especially Elymas sp. and Stipa
sp.  These species mix well with the C-4's and are your best bet for full
season growth.  I'm looking into using C-4 grasses, Cup plant (Silphium
perfoiliatum) and native legumes, esp. lead plant (amorpha canensis) as a
basic summer pasture with a little elymas as an early green up c-3 (Elymas
canadensis is also an excellent nurse crop for prairie development).  I
probably won't graze this until mid summer and stop in early fall when my
C-3 pastures come back in.  At this point I'm not trying to get a full
season mix, just not sure how to do it.  Any ideas on this?
Mark