| |
Introduction
| Soil
sampling and analysis | Fertilizer
decisions | Conclusions
.
Introduction
Producers are faced with an
ever-increasing demand to manage nutrients from fertilizers, manure and
other sources. Environmental concerns, combined with economic optimization
means that a farmer must balance crop nutrient requirements with applied
nutrients from fertilizer and manure, and that mineralized from the soil.
The decision process is no longer just on the back of an envelope. The new
reality will be that each producer must be able account for nutrients in
their farm operation. To accomplish this, producers will require tools to
make nutrient management decisions.
Fertilizer nutrients for crop
production are essential for sustainable agriculture, but optimization is
dependent upon agro-climatic conditions, soil moisture levels, and
economics. Alberta farmers spent an estimated $505 M on fertilizer in
2000, up from $274 M in 1990. However, in the recent past number of years,
nitrogen fertilizer prices have increased as a result of increased natural
gas prices. This combined with declining grain prices, has forced many
farmers to reduce nitrogen fertilizer application. In addition, much of
the province has also suffered from extensive drought conditions. This has
resulted in decreased revenues for farmers and increased government
assistance. Since fertilizers account for 10-40% of farmers input costs
depending on crop and soil zone, it is critical that a farmer optimize his
nutrient management in relation to crop selection, expected crop prices,
soil nutrient levels and moisture conditions. Optimal nutrient management
and balanced fertility insures high crop production for human and
livestock consumption and forms the foundation of value added agriculture.
Efficient nutrient use will also ultimately reduce environmental risk.
Nutrient management is a vital component of environmental farm management,
reducing the impact on the nutrients on the environment and increasing
consumer confidence in food production and safety. Using optimal
fertilizer rates will have a resource conservation benefit since
fertilizers are produced from non-renewable resources. Optimizing the
amount of nitrogen and phosphorus used in the province will result in
reduced potential for negative environmental impact such as nitrate
leaching, denitrification, greenhouse gases (N2O), and
phosphates in surface water. Nutrient management tools include soil
sampling and analysis, nutrient decision software, and on-farm
testing.
Soil Sampling and
Analysis
Soil sampling and analysis is an index for
nutrient availability in soil and is a critical step in nutrient
management planning. Soil sampling technique, timing of sampling and type
of analysis need to be considered for accurate results.
Soil
variability is a major concern when deciding how to collect a
representative soil sample. Soil samples submitted for analysis should be
representative of the field. Therefore, by sampling from an area of the
field where yield is typically average, soil test results should come back
with an average representation of the field. Identifying areas that are
representative can be difficult without a first hand knowledge of the
field. If the person taking the soil samples does not take the time or
have the knowledge required to take a sample in the appropriate location,
the results can come back somewhat sporadic.
Random soil sampling
is the traditional approach that works for uniform fields with little
variation. Managed random sampling technique samples from areas identified
as average production areas. This is different from random sampling, which
provides an average of all cores taken throughout your field. Managed
random sampling is recommended if you cannot identify a dominant
production area on your field.
For fields with more variability
(hills, pot holes etc), benchmark sampling is recommended. Benchmark
sampling reduces the inherent variability of a field by reducing the area
sampled. A small area (generally about ¼ of an acre) representing the
majority of the field is sampled the same number of times as in random
sampling. This is the reference area from which fertilizer recommendations
are made. It is marked with GPS or other means and returned to for
subsequent years sampling. Sampling from the same area will reduce
sampling variability, and create a better picture of year-to-year changes.
Creating more than one benchmark is recommended if you cannot identify a
dominant production area on your field.
In the first year,
analyzing a few separate benchmark areas will reduce the risk of getting a
sample not representative of the field. Although there are higher analysis
costs, it will help determine what area to use as a benchmark. When
picking a benchmark area, use observable features such as soil colour and
landscape to identify where different soil types occur. Select a site that
has characteristics similar to most of the field or the dominant soil
type. Often the best time to identify different soil characteristics is
through crop development. At the beginning of the growing season
differences in crop establishment and vigour can be seen making a
representative location easier to pick out. Other ways of selecting
potential benchmark sites include the use productivity, yield, aerial
and/or topographic maps.
With growing sophistication, the benchmark
process can be further extended by establishing a couple of benchmark
areas in different areas that allow customization of fertilizer rates. By
identifying a primary benchmark area and a secondary benchmark area and
perhaps even a tertiary benchmark area, a fine-tuned fertility management
strategy can be achieved even without variable rate technology. Dividing a
field into management zones allows for an understanding of different
conditions within a field. This is particularly effective in rolling and
hummocky landscapes. For example, a large depression may be a very
productive area, but a separate soil test may indicate it can be optimized
with a higher rate of nitrogen than the benchmark is indicating. While
most producers do not have variable rate capabilities, rates can often be
easily increased through other adjustments.
Fertilizer
Decisions
Most if not all soil test laboratories will
provide a nutrient recommendation based on the soil test results and
identified yield goals for a specific crop. This system works well. But if
you want to make some changes to that request like changing a crop, then
you may have to contact the laboratory or make use of their on-line system
to get a new recommendation. Most laboratories do not factor in crop
prices and fertilizer costs. Nor do they factor in individual risk
management.
The Alberta Farm Fertilizer Information and
Recommendation Manager (AFFIRM) software is a farm nutrient management
decision support system. This decision support system allows users such
ag-industry agents, agronomic specialist and farmers to evaluate potential
fertilizer decisions based on crops, agro-climatic regions, moisture
conditions, and production economics. The system allows the user to
compare various cropping options, fertilizer decisions and crop
price:fertilizer cost combinations for various moisture scenarios.
Ultimately, the AFFIRM software will enhance crop production efficiencies
through the delivery of technical information for making nutrient
management decisions. The AFFIRM software is currently being enhancing
with new agronomic management knowledge, a balanced total fertility
economic model and new programming techniques.
Soil, crop,
agro-climatic, management and economic factors influence optimizing
fertilizer requirements for crop production. The interaction of these
factors is complex. AFFIRM (Alberta Farm Fertilizer Information and
Recommendation Manager) is a decision support system designed to assist
the user (provincial and industry agronomists, farm consultants and
farmers) in the selection of optimum fertilizer rates for cereal, oilseed,
forage and special crops. AFFIRM represents the culmination of 30 years
for field and laboratory research regarding fertilizer use for crop
production. The software provides a means of understanding and managing
the interaction of soil nutrient levels, spring soil moisture, growing
season precipitation, crop response to fertilizer nitrogen and the
economics of nitrogen fertilizer costs and crop prices.
AFFIRM has
been available from the Ropin’ the Web site of Alberta Agriculture as a
free downloadable software since 1996. In that time, this software has
consistently been one of the most popular downloads (1900 downloads since
1997) by farmers, industry agents, extension staff, researchers and
students in university courses. As with all software, users have
identified problems, inadequacies, and inaccuracies that now need to be
corrected with new knowledge and current research results. Users have
indicated a need for enhancements for faster data input and multiple field
processing. As internet access speeds improve, a web-based system for the
Alberta Agriculture website is also desired. The economic analysis within
AFFIRM is currently restricted to nitrogen fertilizer crop response. The
economic analysis needs to include other fertilizer nutrient costs to
provide the user with a realistic assessment of the total fertilizer
economics for crop production.
A farm nutrient management decision
support system will provide reliable information for farmers to make
balanced fertilizer and cropping decisions. With the current state of
higher nitrogen fertilizer costs and low soil moisture conditions, farmers
need a tool to optimize their fertilizer requirements based on
agro-climatic conditions, soil moisture levels, soil test results and
economics. A balanced fertility economic model would incorporate the input
costs of all fertilizer nutrients and additional nutrient sources such as
manure for a balanced agronomic and environmental nutrient management for
the farm landscape.
The AFFIRM software is a risk management
decision support system. The results of this project will be management
tool to assist farmers to optimize their fertilizer nutrient management to
sustain high crop production levels that will insure high quality food for
human consumption and feedstock for the livestock industry. Improved
nutrient management efficiency means that crop production input costs will
be reduced and allows crop producers to still operate at lower commodity
prices or under less than ideal climatic conditions.
The AFFIRM
software is a user-friendly nutrient management tool to extend current
research knowledge to make efficient practical fertilizer decisions. It
makes use of current computer technology and the Alberta Agriculture
web-site to deliver an application that the user can customize for his
farm situation. This project provides an opportunity for soil and crop
researchers to work with economic and farm risk managers to jointly apply
their knowledge to develop a decision support system for practical
application of provincial research and economic farm management. The
AFFIRM software will be a valuable tool for the Industry Development
Sector extension agronomists, the business and risk management specialists
and the Ag-Info Centre.
The AFFIRM software is unique in it’s
approach to making fertilizer decisions. Other fertilizer recommendation
software used by soil testing laboratories use a simple target yield
approach. A user selects a yield goal and a recommendation is provided
based on nutrient uptake and soil test levels. Very little consideration
is given for fertilizer costs and crop prices. AFFIRM provides an economic
analysis based on marginal revenue vs. marginal cost for each
10-pound/acre increment of fertilizer nitrogen. It demonstrates the
economic principle that marginal revenue product must be greater than
marginal factor cost for an input to remain economic at a given use level.
AFFIRM provides the expected return from each dollar spent on fertilizer
nitrogen and how this return changes with changes in the dollars spent on
nitrogen fertilizer. The producer understands how to reduce risk regarding
fertilizer decisions based on economic principles of diminishing returns.
However, the economic impact of other fertilizer nutrients and other
sources of nutrients need to be included in the economic analysis, and the
economic benefits of protein management for such crops as wheat and malt
barley.
Balanced fertility management not only includes nutrient
sources and economic costs, but also the crop requirements. Nutrient
ratios of soils and crops must also be managed to optimize crop
production. Crops such as canola need specific Nitrogen:Sulfur ratios to
achieve high levels of production from increased nitrogen fertilizer.
Currently AFFIRM only provides recommendations to insure nutrients such as
phosphorus, potassium, sulfur and micro-nutrients are adequate for a range
of nitrogen fertilizer rates and does not maintain balanced nutrient
ratios for optimal crop production.
AFFIRM provides a means of
understanding the impact of moisture on crop production and fertilizer
requirements. Growing season precipitation is critical for crop production
and optimum fertilizer application. AFFIRM uses historic precipitation
probabilities to estimate expected growing season precipitation. It also
uses potential water storage by the soil to indicate importance of soil
moisture conservation. Even for areas under irrigation, AFFIRM indicates
the impact of various irrigation levels of management on crop response to
nitrogen fertilizer and other nutrient requirements.
Enhancements
to the AFFIRM software include:
- Expansion of the crop nutrient database with nitrogen mineralization
estimate and historic climate data.
- Improved fertilizer nitrogen guidelines and recommendations for crop
production based on residual soil test nitrogen plus potential nitrogen
mineralization.
- Update of precipitation probabilities for agro eco-districts
- Easy access to current nutrient management research and knowledge.
- Expanded nutrient economic analysis model for complete crop
fertilization.
- Field and whole farm optimization for nutrient management.
- Enhanced user-friendly software with easy information inputs and
graphic outputs.
- Downloadable software from the Alberta Agriculture website.
- Web-based access to information through the Alberta Agriculture
website.
- Nutrient management tool for the Ag-Info Centre.
- Complete user guide documentation and tutorials.
A new
component being added to AFFIRM is the impact of nitrogen mineralization
on crop response to fertilizer. Work is currently under way to improve
crop response functions by incorporating this nitrogen
source.
Other nutrient management software
AFFIRM is not
the only software that can help with nutrient management. Other nutrient
management software that are available or under development include:
- Manure Management Planner
- Money Map
On-farm testing
An important
consideration for nutrient management is on-farm testing (OFT). On-farm
testing is field-scale, scientifically valid research established and
managed by the farmer with field-scale equipment. It is replicated, sound
research that enables the farmer to explore and evaluate various
production options. Farmer participation leads to more appropriate
site-specific technology, broader and faster adoption, and increased
producer ability to adapt and incorporate environmentally sound and
profitable farming practices. The following steps are essential for a
successful on-farm testing project.
- Establish goal and objectives.
- Selection of treatments and the check plot or control.
- Site selection.
- Design and layout of the experiment on the selected site.
- Data collection and record keeping.
- Evaluation, analysis and interpretation of results using statistical
procedures.
- Sharing results.
On-farm testing (OFT) has the potential to
enhance farming practices by putting experimental methodology in the hands
of the farmer. The successful farmer needs to trim costs, maintain
profitability, and reduce potential adverse effects on the cropland
resource and environment. Developing effective improvements requires
decisions based on accurate information that applies to the farmer’s soil,
landscape, climate, and equipment. On-farm testing is an accurate,
efficient way to get the information needed to make the right decisions.
To be effective, farmers must combine technology and agronomic knowledge.
To predict the where and when of soil and crop management, it is essential
to know the how and why of crop growth, soil processes and landscape
variability, by conducting farm and field specific applied
research.
Conclusions
AFFIRM provides crop response data
and economic analysis and/or fertilizer recommendations for a wide range
of cereal, oilseed, forage and special crops. Farmers grow various
combinations of these of these crops based on rotations, expected crop
prices or land and climate limitations. Farmers have a limited budget for
fertilizers and maximizing the return for each fertilizer dollar for all
crops and fields is critical for a successful farm operation. The ultimate
benefit of successful crop production is reduced need for farm aid
programs and high quality food for domestic and international
consumption.
Acknowledgements
This project would not be
possible without the contributions of the following individuals, companies
and committees: Alana Kelbert (Research Agrologist), Renn Breitkreuz
(Production Economics), Guangzhi Liu (Software Development), Roger
Andreiuk (Norwest Labs), Dr. Ross McKenzie (Research Scientist), Dr. Regis
Karamanos (Westco), Norwest Labs and AESA Soil
Quality.
References
- Kryzanowski, L.M. 1987. How to get the most from your soil test
report. Agdex 533. Alberta Agriculture.
- Kryzanowski, L. (editor) 1988. Soil Test Recommendations for
Alberta: Technical Manual. Alberta Agriculture, Food & Rural
Development.
- Kryzanowski, L.M. and R.H. McKenzie. 1991. FERT92: Irrigated crop
fertilizer recommendation program. Computer tools for soil and water
conservation proceedings.Edmonton, AB. December, 1991. p 232-236.
- Kryzanowski, L.M., R.H. McKenzie, K. Cannon and A. Middleton, 1995.
Interaction of nitrogen and moisture on the yield response of wheat,
barley and canola. Western Canada Agronomy Workshop, Red Deer, AB, July
1995. p274.
- Kryzanowski, L.M. 1995. AFFIRM: Alberta Farm Fertilizer Information
and Recommendation Manager (AFFIRM). PARI: Parkland Agriculture Research
Initiative, Conservation Workshop, November 1995. p 31-33.
- Kryzanowski, L. 2001. On-farm testing. In Proceedings of the
2001 Site Specific Management Conference and Trade Show. Alberta
Agriculture, Food & Rural Development. p 180-188.
- McKenzie, R.H., L. Kryzanowski, A.B. Middleton and H.H. Janzen.
1992. Effects of stored soil moisture, growing season precipitation and
fertilizer on spring wheat yields. Alberta Soil Science Workshop.
Lethbridge, February 19-20, 1992. p 125-135.
- McKenzie, R.H. and L. Kryzanowski. 1993. Fertilizing irrigated grain
and oilseed crops. Agdex 100/541-1, Alberta Agriculture.
Len Kryzanowski, P.Ag.
Crop Nutrition
Research Agronomist
Crop Diversification,
AAFRD
2nd floor, Agronomy Centre, 6903 - 116
street, Edmonton AB T6H 5Z2 |
|