Previous to this past season, I worked hard getting some
starter fertilizer (300 pounds/acre bonemeal at 6.5-18-0)
through the planter with my corn and soybeans. This past year,
due to circumstances, I could only broadcast poultry compost
(either 1 ton or 1/2 ton per acre at 5-3-2). I didn't really
see much difference in yield.
As conventional farmers we were long taught to apply at least
some of our starter fertilizer through the planter (especially
important for P). Does this assumption still hold for an organic
regime? You might imagine that it would be even more important
for compost, since the nutrients are not so readily available,
but who really knows? Do you have any actual data showing
how much yield loss we might expect by broadcasting only?
As you might guess, I will need the answer quite soon if
I am to change my plans.
Thanks for the very good questions on fertilizer and the
differences between conventional programs and organic strategies.
The most important conceptual difference is that in a conventional
system you tend to have a "put and take" philosophy.
You put what the plant needs for this season into
the soil and take out your harvest at the end. Organic
systems tend to be very different. In these systems, we look
at building up basic soil fertility so that the soil is growing
the plant (not the highly soluble fertilizers). In conventional
systems with corn, many growers will plant their seed as early
as possible. In these colder soils, phosphorus can be an issue
in getting good seedling vigor, so starter fertilizers show
a quick response.
Generally speaking, organic farmers, using untreated seed,
will plant later in the planting window when the soil is a
few degrees warmer. These warmer soil temperatures often negate
the benefits of conventional starter fertilizers. This would
be true for the compost as well.
Your goal should always be able to maintain good soil fertility
by using a sound crop rotation, a cover crop program based
on legumes for nitrogen fixation and compost applications
for micro-nutrients and carbon. I also suggest you sample
the soil in your fields once a year or at least every other
year to track the impact of your soil-building program.
If you have access to compost, I suggest you apply it to
your fields somewhere in the rotation where it can be incorporated
with ease. We put ours into the rotation in late summer right
before we till for wheat. This means our fields get compost
about once every four years. We put it on at about 8 to 10
wet tons per acre. Most of our nitrogen comes from legumes,
and we’ll buy potassium in the form of mined potassium
sulfate if we need it.
Hope this helps,