|
Putting It All Together
generally, the type of soil management that gives
the greatest immediate
return leads to a deterioration of soil productivity, whereas the
type that
provides the highest income over the period of a generation leads
to the maintenance or improvement of productivity.
Charles Kellogg, 1936
In
this chapter, we'll give some guidelines on how you can promote high quality
soils by adopting practices that maintain or increase soil organic matter,
develop and maintain optimal soil physical conditions, and promote top-notch
nutrient management. In earlier chapters of Part Two, we discussed many
different ways to manage soils, crops, and residues, but we looked at
each one as a separate strategy. In the real world, we need to comine
a number of these approaches and use them together. In fact, each practice
is related to, or impacts, other soil heath promoting practices. The real
key is to modify and combine them in ways that make sense for your farm.
We hope that you
don't feel as confused as the person on the left in the drawing on the
next page. If the thought of making changes on your farm is overwhelming,
you can start with only one or two practices that improve soil health.
Not all of these suggestions are meant to be used on every farm.
Decisions on the
farm need to support the economic
bottom line. Research shows that the practices that improve soil health
generally also improve the economics of the farm, in some cases dramatically.
However, you need to consider the fact that the increased returns may
not be immediate. After implementing
new practices, soil health may improve at a slow rate and it may take
a few years to see improved yields. A "learning period" is probably
needed to make the new management practices work on your farm. Permit
yourself to make a few mistakes. Changing management practices may involve
an investment in new equipment. For example, changing till age systems
requires an investment in new tillage tools and planters, and the bottom
line may not improve immediately. For many farmers, the short-term limitations
may keep them from making these changes, even though they are hurting
the long-term viability of the farm. Big changes are probably best implemented
at strategic times. For example, when you are ready to buy a new planter,
consider a whole new approach to tillage as well. Also, take advantage
of flush times, when you receive high prices for products, to invest in
new management approaches. However, don't wait until that time to make
decisions. Plan ahead, so you are ready to make the move at the right
time.
General
Approaches
There are many options
for making soil management changes in different types of farming systems.
Let's go over the general approaches that can be used for most types of
agriculture. If at all possible, use rotations that utilize grass, legume,
or a combination of grass and legume sod crops, or crops with large amounts
of residue as important parts of the system. Leave residues from annual
crops in the field or, if you removed them for composting or to use as
bedding for animals, return them to the soil as manure or compost. Use
cover crops when soils would otherwise be bare to add organic matter,
capture residual plant nutrients, and reduce erosion. Cover crops also
help maintain soil organic matter in resource-scarce regions that lack
possible substitutes to using crop residues for fuel or building materials.
Raising animals
or having access to animal wastes from nearby farms gives you a wider
choice of economically sound rotations. Rotations that include perennial
forages make hay or pasture available for use by dairy and beef cows,
sheep, and goats. In addition, on mixed crop-livestock farms, animal manures
can be applied to cropland. It's easier to maintain organic matter on
a diversified crop-and-livestock farm, where sod crops are fed to animals
and manures returned to the soil. However, growing crops with high quantities
of residues plus frequent use of green manures and composts from vegetative
residues helps maintain soil organic matter even without animals.
You can maintain
or increase soil organic matter more easily when you use reduced-tillage
systems, especially no-till, instead of the conventional moldboard plow
and disk system. The decreased soil disturbance under reduced tillage
slows the rate of organic matter decomposition and helps to maintain a
soil structure that allows rainfall to infiltrate rapidly. Leaving residue
on the surface encourages the development of earthworm populations, which
also improves soil structure. Compared with conventional tillage, soil
erosion is greatly reduced under minimum-tillage systems, which helps
keep the organic matter and rich topsoil in place. Any practice that reduces
soil erosion, such as contour tillage, strip-cropping along the contours,
and terracing, also helps maintain soil organic matter.
Even if you use
minimum-tillage systems to leave significant quantities of residue on
the surface and decrease the severity of erosion, you also should use
sound crop rotations. In fact, it may be more important to rotate crops
when large amounts of residue remain on the surface. Decomposing residues
harbor many insect and disease organisms. These problems may be worse
in monoculture with no-till practices than with conventional tillage.
Test your soils
regularly and apply lime and fertilizers only when they are needed. Testing
soils every two or three years on each field is one of the best investments
you can make. Make sure that you properly credit the N contribution of
a decomposing sod or the N, P, and K contributions from manures. If you
keep the report forms, or record the results, you will be able to follow
the fertility changes over the years. Monitoring soil test changes will
help you fine-tune your practices. Soil testing laboratories usually charge
extra for an organic matter determination, but it's worth the money every
few years just to track changes. Also, if you're interested in soil microorganisms,
there is now a laboratory that can help you. In dry areas, salt accumulation
may be a problem. You may need to use gypsum or other leaching salts.
Also, maintain your pest scouting efforts and keep records over the years.
This allows you to evaluate improvements in this area.
It's the Combination...
Farmers are learning that the combination of
reduced tillage, cover crops, and better rotations can have
a dramatic effect on their soil and the health of crops. They
are finding that, by combining practices, they are reducing
pest damage, improving soil tilth, vastly reducing runoff
and erosion, increasing soil organic matter, and producing
better crop growth. Each practice by itself is worthwhile.
However, the greatest strengths and benefits are derived from
combining a number of key practices.
For example, on the Groff
farm, it's the combination of good rotations, integrating
livestock with crops, using no-till and cover crops that all
work together to produce high-quality soil and crops. |
There is no substitute for taking a little time each year
to observe your soils for such things as indications of compaction,
the presence of earthworms, the health of roots or other indicators
we discussed in chapter 20. The saying
"The farmer's footprint is the best fertilizer" can be
modified to "The farmer's footprint is the best path to improved
soil health." If you don't already, begin to regularly observe
and record the variability in crop yield across your fields. As
equipment changes are made, you might consider buying a yield monitor
that allows you to track yields on a field. Or, simply take the
time to track production from the various sections of your fields
that seem different. Compare your observations with your soil sampling
plan, so you can be sure that the various areas within a field are
receiving optimum management. Perhaps the hilltop or sideslope would
benefit from additional manure or compost, while none is needed
in other portions of the field.
What
Makes Sense on Your Farm?
What makes sense on
any individual farm depends on the soils, the climate, the nature of the
farm enterprise itself and the surrounding region, potential markets,
and the family's needs and goals. The specific details of implementing
general management approaches depend primarily on the type of farm enterprise:
grain or vegetable crops only, integrated crop-livestock, organic or not,
etc.
Most grain crop
farms export a lot of nutrients and are managed with a net loss of organic
matter. However, these farms provide a great deal of flexibility in adopting
alternative soil management systems because there is a wide range of equipment
available for grain production systems. You can promote soil health easily
with reduced-tillage
systems, especially no-till and zone-till, instead of the conventional
moldboard plow and disk system. Well-drained, coarse-textured soils are
especially well adapted to no-till and zone-till systems, and the finer-textured
soils do well with ridge-tillage or zone-tillage systems. Regardless of
the tillage system that is used, you should try to travel on soils only
when they're dry enough to resist compaction. However, managing no-till
cropping on soils that are easily compacted is quite a challenge because
there are few options to relieve compaction once it occurs. Maintaining
controlled traffic zones or using some tillage to break up compacted layers
may be necessary on such soils.
Even if you use
minimum-tillage systems that leave significant quantities of residue on
the surface and decrease the severity of erosion, you also should use
sound crop rotations. Consider rotations that utilize grass, legume, or
a combination of grass and legume perennial forage crops. Raising animals
on what previously were exclusively crop farms, cooperating on rotations
and manure management with a nearby farm, or growing forage crops for
sale to a beef or dairy farm gives you a wider choice of economically
sound rotations and at the same time helps to cycle nutrients better.
Incorporating these innovations into a conventional grain farm often requires
investment in new equipment and creatively looking for new markets for
your products. There also are many opportunities to use cover crops on
grain farms, even in reduced tillage systems.
Organic grain
crop farms do not have the flexibility in soil management that conventional
farms have. Tillage choices are limited because of the reliance on mechanical
methods instead of herbicides to control weeds. On the positive side,
organic farms already rely heavily on organic inputs through green and
animal manures and composts to provide adequate nutrients to their crops.
A well-managed organic farm usually uses many aspects of ecological soil
management. However, erosion may remain a concern because many organic
farms use clean and intensive tillage. It is important to think about
reducing tillage intensity and perhaps invest in a better planter. New
mechanical cultivators can generally handle higher residue and mulch levels
and may still provide adequate weed control. Try to look into ways to
increase surface cover, although this is a challenge without the use of
chemical weed control. Alternatively, you should consider conventional
erosion control practices, such as strip cropping, as they work well with
rotations involving sod and cover crops.
Diversified crop-and-livestock
farms have an inherent advantage for improving soil health. Diversified
crop-and-livestock farms have an inherent advantage for improving soil
health. Crops can be fed to animals and manures returned to the soil,
thereby providing a continuous supply of organic materials. For many livestock
operations, perennial forage crops are a logical part of the cropping
system, thereby reducing erosion potential and improving soil physical
properties. Livestock-based farms also have some disadvantages. It is
more difficult to adopt minimum tillage practices when sod crops are rotated
with row crops, and the need to incorporate
manure requires at least some type of tillage. You should still consider
minimizing tillage by trying to inject the manure or chiseling it in,
rather than plowing it under. Also, minimize soil pulverization by reducing
secondary tillage and establishing the crops with no-tillage (or zone-tillage)
planters.
Preventing soil
compaction is important on many livestock-based farms. Manure spreaders
are typically heavy and frequently go over the land at very unfavorable
times, doing a lot of compaction damage. Think about ways to minimize
this. In the spring, allow the fields to dry adequately (do the ball test)
before taking spreaders out. If there is no manure storage, building a
structure to hold it temporarily allows you to avoid the most damaging
soil conditions.
Livestock farms
require special attention to nutrient management, making sure that the
organic nutrient sources are optimally used around the farm and that no
negative environmental impacts occur. This requires a comprehensive look
at all nutrient flows on the farm, finding ways to most efficiently use
them, and preventing problems with excesses.
Soil quality management
is especially difficult on vegetable farms. Many vegetable crops are sensitive
to soil compaction and often pose greater challenges in pest management.
These cropping systems, therefore, can greatly benefit from improved soil
health. Most vegetable farms are not integrated with livestock production,
and it is difficult to maintain a continuous supply of fresh organic matter.
Bringing manure, compost, or other locally available sources of organic
materials to the farm should be seriously considered. In some cases, vegetable
farms can economically use manure from nearby livestock operations or
swap land with them in a rotation. Farms near urban areas may benefit
from leaves and grass clippings and municipal or food waste composts,
which are increasingly becoming available. In such case, care should be
taken to insure that the compost does not contain contaminants.
Vegetable cropping
systems are generally well adapted to the use of cover crops because the
main cropping season is generally shorter than those for grain and forage
crops. There is usually sufficient time for growth of cover crops in the
pre- or post-season to gain real benefits, even in colder climates. Using
the cover crop as a mulch (or importing mulch materials from off the farm)
appears to be a good system for certain fresh market vegetables, as it
keeps the crop from direct contact with the ground, thereby reducing the
potential for rot or disease.
The need to harvest
crops during a very short period before quality declines regardless of
soil conditions often results in severe compaction problems on large vegetable
farms using large-scale equipment. Controlled traffic systems, including
permanent beds, should be given
serious consideration. Limiting compaction to narrow lanes and using other
soil-building practices in between them is the best way to avoid severe
compaction damage under those conditions.
The
Future
Each of the farming
systems discussed above has its limitations and opportunities for building
better soils. Although there are ways to improve soil health in any system,
the details may differ. Whatever crops you grow, when you creatively combine
a reasonable number of practices that promote high quality soils, most
of your farm's soil fertility problems should be solved along the way.
The health and yield of your crops should improve. The soil will have
more available nutrients, more water for plants to use, and better tilth.
There should be fewer problems with diseases, nematodes, and insects.
By concentrating on the practices that build high quality soils, you also
will leave a legacy of land stewardship for your children and their children
to inherit and follow.
Top
|