| What benefits are possible that make it worth
paying attention to the biological side of soils in addition to the
chemistry and mineral fertility? Are there any economic benefits
that can make a real difference to net farm income?
The
answer to that question is a big YES!
A spoonful of healthy
soil contains many millions of beneficial microscopic organisms of
various kinds that include beneficial species of bacteria, fungi,
nematodes and protozoa that never cause disease or become pests.
These are helpful species that perform vital "functions" in the root
zone that can bring real profits to growers IF soil
conditions are managed in ways that allow the microbes to live and
work.
Think about the dollar potential involved with each of
the following six functions and then be aware that these functions
are entirely biological and only occur through a soil foodweb
that is built up, intact and working!
Decomposition of
crop residues, manure and other organic material: These
materials will only decompose if certain species of fungi and
bacteria, the "decomposers", decay them and allow recycling
processes to occur. The ideal process forms large amounts of humus.
The decay function gets rid of crop residues, but what it really
does is convert the food energy in fresh organic matter to a form
that feeds other soil organisms that do different indispensable
functions, as described below.
Retention of nutrients:
Nitrate and some other nutrients can leach out and be lost
unless they can be banked in soils until the plant needs them. The
function of nutrient retention occurs when bacteria and fungi
multiply and increase their populations in the soil. Bacteria and
fungi are extremely rich in protein that is made from nitrogen. When
bacteria and fungi multiply they gather up free nitrogen from the
soil and convert it to protein in their bodies. Nitrogen in this
form is a bank account of convertible nitrogen that will not leach
away or be lost as a gas. Products and cultural practices that
stimulate a "bloom" of bacteria or fungi reproductive growth can be
used as tools to achieve nutrient retention. When this function is
working in your soil you can begin to apply lower rates of N and P
with no reduction in crop yield.
Nutrient Recycling:
Once nutrients have been retained, other kinds of soil organisms can
be encouraged that feed on the bacteria and fungi. The rich meal of
protein is metabolized and released back into the soil as ammonium
that is quickly converted to nitrate for use by crops. The organisms
that perform this function are beneficial nematodes that only feed
on bacteria or fungi, the protozoa that feed on bacteria, and
beneficial soil mites that feed on fungi. As these species go about
their work they cause nitrogen especially, but also phosphorus and
other nutrients, to be released at a gradual rate that supplies
crops with a steady diet all season long.
Biological
control of root rot and parasitic nematodes: A healthy soil that
contains a broad diversity of microbial types most often contains
species that kill, inhibit or suppress the kinds of fungi that cause
root rots and the kinds of nematodes that attack roots. There is
plenty of research and on-farm experience to show that these
economic threats can be controlled very well without the need for
applied fungicides and nematicides. What it takes for this to happen
is good soil health in the form of an active, intact soil
foodweb.
Production of plant growth regulators: All
plants depend on the presence of certain species of soil
microorganisms in the root zone to produce various hormones and
other chemical "signals" that stimulate growth and development. Two
plants from the same seed, one in a dead soil and the other in a
living soil, both with the same nutrients, will show different rates
of growth, final size and value. The plant growing in healthy soil
will have found the partnership it expects with beneficial microbes
that produce growth hormones not made by the plant itself. The plant
in healthy soil will be the better plant.
Soil structure
and tilth: Enjoying the very best tilth depends on maintaining
an aggregated or crumb soil structure. This is the ideal soil
structure that allows for the optimum infiltration of air, water and
roots systems. The formation of soil aggregates is mostly a
biological process under the control of certain types of organisms
in the soil foodweb. Aggregates will not form unless many sand, silt
and clay particles are "glued" together by the gums and gels that
only certain species of soil bacteria can produce. These aggregates
are further strengthened against melting or collapse by certain
species of beneficial fungi that grow throughout the aggregate and
physically bind it. It is impossible for a soil to maintain the
ideal crumb structure in the absence of the particular species of
bacteria and fungi that perform the gluing and binding
functions.
Clean up of herbicide or pesticide carry
over: Most herbicide and pesticide molecules can be "eaten" or
degraded by certain kinds of microbes in the soil, if those species
are present. A healthy soil will tend to rid itself of ag chemical
carry over and other forms of pollution.
Each of the
functions above describes ,how soils ate supposed to work and can
work. Your opportunity is to help customers learn to employ cultural
practices and biological products to get all these functions working
at top capacity. Yield and profit will be the
result. |