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Herd of cattle

About the ARM System
(Application Risk Management)

While anyone can use the ARM guidelines, the complete use of the

ARM system, including early season application, is intended to

function in tandem with your custom Farm Plan and a professional

field risk assessment.  We encourage operators to work cooperatively with WCD to monitor and adapt your ARM Plan as necessary. Use of this system without the proper analysis may not result in low risk applications.


Please call WCD to get started today (360) 526-2387

The ARM Weather Map is your first line of defense against having a runoff event. It’s primarily purpose is to identify those conditions that could lead to runoff.  Use of this tool is especially important in the high risk wet seasons when soil saturation and large rain events are more frequent. Both of these factors can readily move nutrients, pathogens, and sediment from your field.

Components of the ARM System:
What is Application Risk Management (ARM?)

Part of properly managing your nutrients is knowing how to apply them in such a way that minimizes the risk of pollution while also maximizing uptake to plants. This ARM system was developed by WCD to help you through the process of properly assessing, managing, and reducing the risks associated with applying manure to your fields. The system is meant to be used in conjunction with your Nutrient Management Plan, which lays out how to individually manage each of your fields and the specific risks associated with each field.

Using a combination of existing NRCS guidelines, field data, and new science, the Whatcom Conservation District developed the ARM system as an addition to the Dairy Nutrient Management Plan. This system and its tools were created, in part, to address the surface and ground water quality issues we can see when manure application coincides with increased rainfall (Spring and Fall) and unsuitable field conditions (i.e., high water table, high soil moisture, standing water, etc). 

The ARM  system allows you, the producer, to assess the risk of applying manure at any given time of the year. Using this tool, you may have the opportunity for early season application to low risk forage fields, providing nutrients (N) to forage at times when plants have increased nutrient needs (Mar-Jun). This tool might also help you to discover that certain fields may not be suitable for low risk application until May, June, or even July. Once completed, you will be asked to send the worksheet to WCD prior to application. This will ensure that you have gone through the analysis process correctly and also allows us to offer feedback when necessary. Alerting us of your intent to apply enables us to properly address inquires and communicate that your application of manure is being done properly according to your plan specifications.


When to use the ARM system:


The ARM system should be used year round, but is particularly important during periods of high risk due to increased rainfall (Oct-March).​ Since manure application after September has limited benefit for crops, and is at a higher risk for runoff and leaching, we encourage you to cease application in September instead of October. Plan your manure storage to avoid manure application between October and March if possible. This will greatly reduce your risk of late season nutrient runoff, winter leaching, and preserve the fertilizer value of your manure. If you do not have sufficient storage for the wet season and need to make an Emergency Winter Application, the ARM Worksheet can help you identify your most suitable fields. If you don't have any areas available for low risk manure application consider exporting your manure to another agricultural operation. 

Manure Application Parameters
  • Forecast

  • Water Table Depth

  • Soil Moisture

  • Field Characteristics

  • Forage Density

  • Application Method

  • Application Setback Distances

  • Vegetative Buffers

High Risk

A high risk field is one that is likely to have a runoff event and/or impact an adjacent waterbody. High risk fields are saturated (over 90% moisture = you could not drive a tractor on it, water appears under your footprint, a handful of soil would produce moisture on your hand), has a water table within 24 inches of the surface and/or flowing tiles, is frozen more than one inch down, has thin vegetation (<70% density), and/or has high risk areas. High risk areas are swales, trenches, ditches, ponded areas, or other conduits that would channel water from the field to adjacent water way. Do not apply to high risk fields! Wait for them to become more suitable before applying.

Low Risk

A low risk field is one that has a low chance for a runoff event. Characteristics include, well drained, sandy soil; low soil moisture; no adjacent waterways or a upslope or berm that prevents water from entering waterway; no swales that lead to a critical area; adequate vegetation cover if surface applying; and no ponding or water table within two feet of the surface. If you can drive a tractor on your field without causing mud or ruts, it is likely at a low risk state.

About the Forecast

The forecast used for the ARM Weather Map comes from model precipitation prediction data by NOAA. This data is updated at least once daily.

Please note, even if this worksheet says it is okay to apply, it cannot account for every variable or condition present on your field. It is your responsibility to use your best judgment and adhere to all application guidelines outlined in your plan. Always err on the side of caution to prevent unwanted discharges. Manure application practices that cause a discharge can lead to fines and/or necessitate a CAFO permit for your facility. The Whatcom Conservation District and the NRCS assume no responsibility for inappropriate manure application. Proper application is ultimately your responsibility.

If at anytime you have questions related to this Worksheet or the ARM system, please call:
Whatcom Conservation District
(360) 526-2387

Printable ARM Resources:

  • Application Risk Management (ARM) Worksheet - We recommend using the online ARM Worksheet linked through the ARM Weather Map in order to automatically capture local precipitation data. However, you may also use this printable form to fill out manually. Save this worksheet to your desktop and fill it out for EACH of your fields individually prior to EVERY application.

  • ARM Field Assessment Worksheet - Print a copy and use this worksheet when you are out in the field assessing your fields prior to filling out the ARM Worksheet and applying.

WARNING: If you choose not to adhere to the guidelines presented on this Worksheet and apply manure without doing the necessary analysis, you may be subject to penalties by a State regulatory agency (i.e., WSDA, or DOE)

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