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Energy Estimator is an energy consumption awareness tool. This particular tool,
“Energy Estimator: Nitrogen”, is the second web-based energy consumption
awareness tool being built by the Natural Resources Conservation Service. This
second tool helps you identify costs based on your crops and Nitrogen
fertilizer application practices. The first tool concentrated on diesel fuel
used in the production of selected crops across common tillage systems in your
area. Another NRCS tool being built at the present time is for estimating and
comparing energy consumption for different irrigation systems. These tools are
intended to give you an idea of the magnitude of energy savings that you could
incur under different management systems.
Steps to use the Energy Estimator: Nitrogen Tool
Step 1: Getting Started
Begin by reading this important use and interpretation information  .
After reading the important information, enter your zip code, identify the
Nitrogen products that are available in your area, and select the method for
determining your fertilizer cost (cost/ton of fertilizer, or cost/lb of N).
Then click Continue:
Step 2: Crops and Fertilizers
The listed crops are the most widely harvested, non-leguminous crops in the
state that was identified by the zip code you entered. These crops may not be
the most common crops in your immediate neighborhood, but they are significant
crops in your state. Because soybeans are legumes that can fix their own
nitrogen, they have not been included in the list.
Instructions:
-
Enter the number of acres you plant for up to 4 crops. You may run
this tool again to examine additional crops.
- Select the primary nitrogen
fertilizer type (N), used for each selected crop from the drop-down menu.
- Enter
the pounds per acre of commercial N you apply to each selected crop.
- Enter the
price per pound of N or per ton of fertilizer (excluding application and
enhanced efficiency product cost) for each selected crop.
Step 3: Application Methods
Please select your fertilizer application practices for the listed crops, then
click Next. The Energy Estimator will determine your current costs and provide
you with an estimated cost, based on the nitrogen use efficiency determined by
USDA agronomists, for the crop you selected.
Step 4: Alternatives
The table below indicates your nitrogen fertilizer cost by crop under your
current nitrogen management system and compares it with our projected cost
under the most efficient and cost-effective nitrogen management alternative for
the crop(s) you selected. Factors considered in the analysis include
availability, cost and efficiency of nitrogen materials, timing of fertilizer
application, fertilizer placement, and the use of a nitrogen loss inhibitor. This
tool does not provide field-specific recommendations. It evaluates
alternatives based on user input. Application rates for alternative practices
will effectively supply the same level of N to the crop as the user's current
practice.
Assumptions
Why these crops?
The listed crops are the most widely harvested, non-leguminous crops in the state that was identified by the zip code you entered. These crops may not be the most common crops in your immediate neighborhood, but they are significant crops in your state. Because soybeans are legumes that can fix their own nitrogen, they have not been included in the list.
What is commercially purchased N?
Commercially purchased nitrogen fertilizers are the most common N sources used in agriculture. They do not include manures, compost or other organic sources of nitrogen. Common nitrogen fertilizers include:
- Anhydrous ammonia (82-0-0)
- Ammonium nitrate (34-0-0)
- Ammonium sulfate (21-0-0)
- Urea (46-0-0)
- Urea-ammonium nitrate solutions (UAN) 32% nitrogen
- Mixed blends of fertilizers (N-P-K) with various formulas
Monoammonium phosphate (MAP, 11-52-0) and diammonium phosphate (DAP, 18-46-0) are not considered in this tool, but their uses are represented much like urea.
These fertilizers were selected because they are generally available throughout the country. Particular forms of N may not be customarily used for specific cropping systems or may not be available in certain areas, yet are given here as general guidance.
Both monoammonium phosphate (MAP) and diammonium phosphate (DAP) are used widely as fertilizers. While they do deliver some nitrogen, their primary use is as a phosphorus source. Because it is difficult to separate the cost of the individual nutrients in these materials, they have not been included in this version of the tool. Similarly, blended fertilizers (N-P-K) with various formulations are not considered.
How were estimates made?
These estimates are based on the likely environmental losses associated with different aspects of nitrogen management. Standard nitrogen fertilizer recommendations assume that a certain amount of the nitrogen applied will be lost before it can be used by the crop. The amount lost varies with the time of application in relation to the time of maximum uptake by the crop, the form of fertilizer applied and the method of application. The savings estimates are based on the assumption that less nitrogen will be needed if the form, timing and method of application used are the most efficient for the crop being grown.
What are the assumptions?
Commercial nitrogen fertilizer costs utilized in this program (NFAT) are based on April 2007 National Agricultural Statistics Service (NASS) regional fertilizer sales data. Prices within each region are compared and coefficients have been developed comparing each fertilizer material to another within the same region. The coefficients set up a price relationship that take into account price differences for the fertilizer materials in each region of the United States. The relative cost of the fertilizer materials in each region is assumed to remain constant, even though the actual cost may change. The cost of the alternative fertilizer materials indicated in Step 4 depends directly on the fertilizer cost that you provide in Step 2.
The cost savings estimated in the tool reflect reduced nitrogen application rates based on reduced nitrogen losses. All results are conservative estimates of potential loss reductions but do not reflect local climatic or soil conditions. For a better estimate of the nitrogen requirements and potential nitrogen savings on your farm, contact your local Land Grant University. For additional information about ways to save nitrogen fertilizer costs see Want more accurate information?
Want a more accurate estimation?
Nutrient management is highly complex. The Energy Estimator: Nitrogen evaluates the effect of timing and placement of fertilizer materials, and use of enhanced efficiency nitrogen products on crop nitrogen requirements. The web site below provides a summary of additional factors to consider when determining how to cost-effectively apply nitrogen fertilizer to crops. http://msucares.com/crops/fertilizer/index.html
Application Method Definitions
Timing:
Timing refers to the time of year in which the fertilizer is applied. Nitrogen fertilizers are most efficiently used by the crop when they are available during the time the crop is actively growing. Fertilizers applied during the dormant season are more likely to be lost through leaching, runoff and/or volatilization.
For Spring-planted Crops:
Fall = Application is following harvest of preceding crop and before adverse conditions (wet soils, snow, frozen soils) prevent further application.
Spring = Application is within 30-45 days of the planting of the crop being fertilized and generally after adverse conditions (wet soils, snow, frozen soils) have passed.
Fall – Spring split = A portion of the application takes place in the fall, the remainder in the spring, before or after planting. Usually, the amount applied in the fall is greater than the amount applied in the spring.
Spring – Spring split = A portion of the application takes place in the spring before the crop is planted, and the remainder is applied after planting.
For Fall Crops Harvested the following Spring:
Fall = Application is within 30 days of planting the crop and before the onset of adverse conditions (wet soils, snow, frozen soils).
Spring = Application is made to match the crop’s growth pattern and generally after adverse weather conditions (wet soils, snow, frozen soils).
Fall – Spring split = Approximately 1/3 of the application takes place in the fall, at or near the time of planting. The remainder is applied in the spring during the time of active crop growth and generally after adverse conditions (wet soils, snow, frozen soils).
Spring – Spring split = A portion of the application takes place in the spring following fall establishment, but before the crop is actively growing. The remainder is applied later in the spring during the period of active crop growth.
For Fall Crops Harvested in the Winter:
Fall = Application is at or near planting to optimize uptake by the crop. This category includes multiple applications of nitrogen through an irrigation system.
Spring = Application is following harvest of the preceding crop and up to three months before planting of the crop being fertilized.
Spring – Fall split = A portion of the fertilizer is applied following harvest of the preceding crop and up to 6 months before planting the crop being fertilized. The remainder is applied during the period of active crop growth.
Spring - Spring split = This method of application is not appropriate for fall planted crops harvested before spring.
Cool-season Perennials (Period of active growth generally is mid-March to early June and early September to mid-November, depending on location):
Fall = Application is just before or within 30 days of the start of active fall growth and before adverse conditions (wet soils, snow, frozen soils) prevent further application.
Spring = Application is just before or within 30 days of the start of active spring growth and generally after adverse conditions (wet soils, snow, frozen soils) have passed.
Fall – Spring split = About 50% of the total fertilizer is applied in the fall. The remainder is applied in the spring, after the first harvest.
Spring – Spring split = About 50% of the total fertilizer is applied in the spring before the start of active growth, and the remainder is applied after the first harvest.
Warm-season Perennials (period of active growth generally is from mid-April to late September, depending on location):
Spring = Application is just before or within 30 days of the start of active spring growth and generally after adverse conditions (wet soils, snow, frozen soils) have passed.
Spring – Spring Split = The total amount applied is split into equal portions for each cutting or harvest. One portion is applied in early spring, and an equal amount is applied after each harvest, except for the last harvest.
Fall = Fall fertilization is not recommended for warm-season perennial crops.
Placement:
Placement refers to where the nitrogen fertilizer is placed, how it is spread in the field, and whether or not it is incorporated into the soil.
Broadcast = The nutrient material is evenly distributed across the surface of the soil by spreading equipment. It is not incorporated or covered by soil or crop residue.
Surface Band/Sidedress = The nutrient material is applied on the soil surface concentrated in narrow bands, usually 4 to 6 inches wide and spaced 18 to 40 inched apart. The fertilizer material is not incorporated or covered.
Incorporate/ Inject = The nutrient material is broadcast across the soil surface, then mixed thoroughly into the soil within 5 days by a tillage operation. Alternatively, the material is injected 6”-10” below the soil surface in narrow bands. The injection slot is sealed to prevent loss of the fertilizer material.
Form
of Nitrogen:
Common nitrogen fertilizers include:
- Anhydrous ammonia (82-0-0)
- Ammonium nitrate (34-0-0)
- Ammonium sulfate (21-0-0)
- Urea (46-0-0)
- Urea-ammonium nitrate solutions (UAN) 32% nitrogen
- Mixed blends of fertilizers (N-P-K) with various formulas
Although manures, compost and other similar materials are excellent sources of nitrogen, commercially purchased nitrogen fertilizers are still the most common N sources used in agriculture.
Both monoammonium phosphate (MAP) and diammonium phosphate (DAP) are used widely as fertilizers. While they do deliver some nitrogen, their primary use is as a phosphorus source. Because it is difficult to separate the cost of the individual nutrients in these materials, they have not been included in this version of the tool. Similarly, blended fertilizers (N-P-K) with various formulations are not considered.
These fertilizers were selected because they are generally available throughout the country. Particular forms of N may not be customarily used for specific cropping systems or may not be available in certain areas, yet are given here as general guidance.”
Enhanced
Efficiency Product:
Enhanced Efficiency N Product
In accordance with the definitions established by the Association of American Plant Food Control Officials (AAPFCO), “enhanced efficiency products” are products with characteristics that minimize the potential of nutrient losses to the environment. The most common types of enhanced efficiency products are nitrification inhibitors, urease inhibitors and slow- or controlled-release nitrogen fertilizers.
Nitrification Inhibitors – Nitrification inhibitors prevent or slow the conversion of ammonium nitrogen (NH4-N) to nitrate nitrogen (NO3-N). Ammonium nitrogen is held firmly by soil particles and is not as easily lost from the soil as nitrate nitrogen. However, after being converted to nitrate nitrogen, it is vulnerable to losses by leaching and denitrification. Some nitrification inhibitors are nitrapyrin, dicyandiamide (DCD) and ammonium thiosulfate.
Urease Inhibitors – The enzyme urease speeds the conversion of urea to ammonia gas. If the conversion takes place below the soil surface, the ammonia is converted to ammonium, which is tightly bound to soil particles. But, if the conversion takes place on the soil surface or crop residue, there is a high potential for ammonia volatilization and loss of N to the atmosphere. The urease inhibitor blocks the enzyme responsible for the conversion of urea to ammonium. An example of urease inhibitor is NBPT [N-(n-butyl) thiophosphoric triamide].
Slow or Controlled-Release Nitrogen Products – These are products containing nitrogen fertilizer in a form that delays its availability for plant uptake and use after application, or which extends its availability to the plant significantly longer than rapidly-available nitrogen products like ammonium nitrate or urea. These materials fall into two categories: Uncoated – materials from which the nitrogen is slowly available because of physical or chemical properties. Examples of materials in this group are urea formaldehyde (UF), methylene urea (MU), or isobutylidene diurea (IBDU); Coated – these materials have a physical coating (sulfur or polymers) designed to wear or dissolve away from the nitrogen core and allow the fertilizer to be available to the soil and crop. These coatings are designed to release nitrogen to the crop and soil at a rate that matches the uptake characteristics of the specified crop. Because the nitrogen becomes available when the crop needs it, less of the nitrogen material is vulnerable to loss by leaching, denitrification, and/or volatilization. Examples of materials in this group are Osmocote® and ESN®.
For these products to be economically feasible, their cost must be offset by a reduction in the amount of nitrogen used and/or by an increase in yield, either of which is the result of improved nitrogen use efficiency.
[Adapted from University of Kentucky Extension Service Bulletin, and from Association of American Plant Food Control Officials (AAPFCO) Official Publication 59
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