Hairy vetch as a winter crop can accumulate 100-250 lbs
N/acre. The amount of N fixed can vary from year to year
or farm to farm due to environmental conditions such as good or
poor establishment, good or poor biomass production, and those
extra couple of weeks in the spring to fix N before the cover crop
is killed.
According to organic matter mineralization and decay series.... you
can estimate half the total N will be available to the crop the first
growing season... in the 2nd year you will get half again.. in the
3rd year half again..
Thus, if you had 200 lbs N/acre fixed by vetch:
100 lbs N/acre available 1st year
50 lbs N/acre available 2nd year
25 lbs N/acre available 3rd year
On the other hand beans will only contribute 40-60 lbs N/acre if
you harvest off the beans. Note: in comparison if plowed down
as a green manure or top-killed as a mulch, that same soybean crop
would contribute more than 100 lbs N/acre when killed at the
peak biomass/flowering stage.
So, the vetch prior to sweet corn had a lot more to kick in up
front. Plus, sweet corn produces a tremendous amount of organic
matter in comparison to beans. That organic matter is a significant
contribution.
You know, they say that cattleman are "grass farmers."
Perhaps row crop & veggie farmers (especially no-till)
could be called "worm farmers."
In one case the end product is beef, but the way you get
there is paying attention to grazing management and forage
quality.
In the other case the end product is a harvestable crop, but
the way you get there is providing optimum conditions for
worms and their associated banditos the microbial herd.
What else is going on at the Groff farm worth hearing about?
I heard you were able to cut down on fungicide applications for
early blight on on tomatoes, because the no-till mulches cut
down on rain splashing and diseases transmission.
Steve Diver
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