Introduction
Agricultural producers are constantly revising and upgrading production
practices to include the most efficient and economical management
systems. One practice that has received increasing attention over
recent years is the use of various soil additives including: soil
conditioners, soil activators, wetting agents, soil inoculants, microbial
enhancers, soil stimulants, etc. Although promotion of such products
has occurred since at least the late 1800’s, increased fertilizer
and overall production costs have increased producer interest in these
materials. However, many of these products may have questionable benefits
since many have not been exposed to scientific investigation to determine
their effectiveness.
Soil and plant additives may be classified in a number of different
ways based on criteria such as intended use or function, applied method,
quantity to be applied, or origin of the material. To provide consistent
information, most soil scientists and agronomists classify these products
under three main categories: 1) soil conditioners; 2) soil activators
and biological inoculants, and 3) wetting agents.
In general soil additives can be distinguished from fertilizer materials
in that they usually contain no fertilizer nutrients. Thus, these
products are usually not marketed with, nor are they required to provide,
a guaranteed analysis (i.e. 10-34-0 or 32-0-0) like most commercial
fertilizers. Instead manufacturers of such products often suggest
that addition of these materials to the soil will enhance crop production
by improving water and/ or nutrient availability and uptake by plants.
These enhancements are generally said to occur when standard fertilizer
applications are made to the crop at recommended or near recommended
levels, although some products claim to replace or significantly reduce
the need for fertilizers.
Scientific research trials represent the best method for evaluating
the effectiveness of non-traditional soil additives. These techniques
have been utilized for decades to evaluate the effects of new products
and treatments on crop production, and to compare different methods
(soil vs. foliar) rates and timing of application. Most traditional
soil amendments and commercial fertilizer materials have been tested
extensively through research evaluations to document both their benefits
and limitations. Unfortunately, this type of testing is costly and
adequate research funds often are not available to investigate the
large number of new products which are being marketed. Nevertheless,
consumers should be aware of the types of products available and have
some knowledge as to their potential to benefit crop production.
Making Decisions
Soil scientists and agronomists are often called upon to provide opinions
as to the use and effectiveness of new and non-traditional products.
However, due to the large number of these products available on the
market, many have received little or no scientific evaluation. As
a result, the best advice that can be provided to growers is to evaluate
new products carefully and insist upon local or regional research
data (not testimonials) demonstrating product effectiveness and value.
Consider conducting small-scaled field trials on your farm if relevant
information is lacking. Figure one shows an example layout for a product
trial. In addition, the following factors should be considered when
evaluating new products in farm and ranch production systems:
1) Utilize a small area, but one of adequate
size to obtain reliable harvest data.
2) Select a field or location within a field
that is uniform in soil, slope and management history.
3) Check plots (those not receiving the amendments)
managed in a conventional manner should always be included in the
evaluation.
4) At least three or four replications (separate
plots) of each plot or treatment should be installed.
5) Manage all plots exactly the same during
the season except for the difference in treatments.
6) Monitor crop growth and development during
the season to detect treatment differences.
7) Harvest each plot separately. Compare all
the yields for all replications of a particular treatment to look
at variability. If yields for a particular treatment are not consistent,
it may not perform consistently, or the test site may have hidden
variation.
8) Finally, use the average value for each
treatment to compare the different treatments to each other. Then,
evaluate input cost for each treatment compared to anticipated returns.
If product and application costs approach or exceed returns, the treatment
may not be a sound investment.
The purpose of this article is not to suggest that all current and/or
future non-traditional soil additives are of no value. New inventions
and new product development constantly offer the potential to improve
crop yields, crop quality and/or production economics. However, it
is important to stress that proper product testing and evaluation
are critical to verify the potential benefits of new or unproven materials.
When considering the use of non-traditional products, farm managers
should first recognize the needs and requirements of their land and
crops. Thorough consideration always should be given to the benefits
and costs associated with a particular management program. Achieving
“maximum economic yield” relies upon utilization of only
those inputs which will, with reasonable certainty, be expected to
provide a return on that investment.
Figure. 1 Example plot layouts for small-scale product or management
practice comparisons.
Rep 1 |
Rep 2 |
Rep 3 |
|
Check |
Product A |
Check |
Product A |
Product A |
Check |
300 - 500 ft Length |
Width of Planter |
Bulk Field
|
