agroforestry question

Todd M. Bolton tmbolton at erols.com
Sat Jan 22 13:53:59 EST 2000


What kind of tree or crop are you trying to grow in the seeps?  Remember
that the dense root zones of most trees, and I would think on grains as
well, reach to 18 inches below top of grade.  Also remember that roots are
very important in the gas exchange proccess used by trees.  Saturated soils
obviously will preclude gas exchange from occuring and therefore have
significant effect on the health and growth rate of vegetation in wet
areas.  There are, of course, plants that are adapted to wet conditions and
will thrive where your black walnut have a hard time.




TREEFARMER at webtv.net wrote:

> In response to DVK's response about Locust fixing nitrogen: It's my
> understanding that the legume (in this case Locust) must be killed for
> the nitrogen to be released. Some years back we interplanted Black
> Walnuts with Black Locust. The idea was to eventually kill out the Black
> Locust to fertilize the Black Walnuts. Needless to say, the Black Locust
> beat out the Black Walnuts so fast that they effectively choked out the
> Walnuts. It may have worked on a better site, but why waste space on a
> good site growing Black Locust.
>
> Truffler, I'm glad you responded to this problem as I'm running out of
> reasons for low yields in seeps (wet areas). Lack of mycorrhizal fungi
> or some bacteria in seeps seems to be the yield limiter whether one is
> talking of grain yields or board feet.
>
> What can one do to better the environment for these fungi?
>
> Using several years of GPS yield monitoring equipment and mapping we've
> found that yields can't be increased by increasing potash and potassium
> amounts. Also, deep tillage has helped little. The only thing that has
> helped is tiling, but to date the tiled areas can't match the better
> areas of the  field. Even as severe as the drought was here last year it
> was still a 3/4 average yield year. It seems like soil temperature may
> have something to do with it but I haven't had a chance to study this
> realm yet. Sometimes in constructing dry dams for water control as
> little as a few inches are removed for construction of the dam. Yields
> in these areas are drastically decreased eventhough there is plenty of
> "topsoil" left. There seems to be something very important in the top
> few inches of the soil that contributes significantly to the crops
> yield.  I guess I've taken up enough space.





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