March 2019 - 14

Suarez noted cover crops, compost,
carbon-based fertilizers and biostimulants
among ways to increase
organic matter. While tilling and
fumigation may be necessary for potato
growers, they are areas to closely monitor.
" Tillage
practices are needed in
potatoes, but as much as we can reduce
them and protect our biology, that's going
to help, " Suarez said. " Fumigations -
again, we know it knocks down biology.
How can we keep that under control?
We know high salinity is going affect
biology. We know cheap sources are
going to knock down biology. "
Grant Cardon, professor and
Extension soils specialist at Utah State
University, recently spoke at the Idaho
Potato Conference in Pocatello. He
noted that once organic matter starts to
break down, erosion, weeds and disease
are likely to follow.
Cardon said conventional tillage
practices can break down five years'
worth of natural organic matter growth
in about two months.
" Our conventional method of tilling
- depending on my management, how
much I'm tilling, how much organic
matter I'm putting back - I reduce soil
structure in 0.2 years. That's a little over
two months, " he said. " Organic matter
additions are important whenever
possible ... I cannot overcome the lack of
organic matter with a mineral fertilizer
in the long run. "
COVER CROPS
Postharvest planting of cover crops
is a way to protect and enrich soil. Not
only do they cover the ground during
winter months, but they have biological
benefits as well.
" We're adding organic matter to the
system though the cover crop, " Cardon
said. " We can keep those roots there, we
can turn the plant back later if we want
to as a green manure crop. It promotes
aggregates ... and microbial activity
when we would otherwise not have that
growing, living system. "
Cardon added that a good cover crop
rotation will also reduce the likelihood
of disease, pests and weeds.
" That reduces the need for chemicals, "
he said.
Cardon was asked what makes for a
good cover crop selection. He said a mix
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Spudman.com
of a legume, such as clover or Australian
winter pea, with a variety of grass, such
as one of the bromes, is considered a
good way to go.
" As growers, we know
that soil health means
better ROI. "
- Edwin Suarez, agronomist at
Midwestern BioAg
You get this contribution from the
legume with nitrogen buildup and
enhancement of soil nitrogen storage, "
he said. " Grass crops have deeper roots
zone so you can take excess nutrients
and break them up into the soil red
zone and turn them back into a slowrelease
nutrient.
" A good mix of legume and grass crop
is typically what people will promote to
get the double-bang for the buck. "
PRESENCE OF HEALTHY SOIL
The presence of earthworms is the
more simplistic (and cheapest) way
to
detect
healthy
soil, Suarez
said.
He recommends the mustard test of
mixing dry mustard with water, which
will draw earthworms to the surface.
The presence of mycorrhiza, a whitecolored
fungus, also is a good indicator.
Cardon echoed earthworms as a
good sign, and added that healthy soil
is typically denser and darker. He also
said scientific study has shown that the
smell of earthworms release endorphins
in the human brain, giving humans sort
of a natural indicator.
" They have such a sweet, fresh smell, "
he said.
There are, of course, much more
scientific and in-depth ways to measure
soil in laboratories, which, as Suarez
noted, tend to come at a cost. Again,
he stressed ROI when it comes to soil
monitoring. Unless the measurements
are driving decision-making, they are
unnecessary.
" Everything you measure should be
applied in management, " Suarez said.
" Data is useless unless it transfers into
actions. "
http://www.Spudman.com
March 2019

Table of Contents for the Digital Edition of March 2019
