Applicators for Round Balers

2024 - Selection Guide
(Applicator Part Numbers)

Hay preservative can be used to bale large round bales between 16% and 30% moisture. You have the option of a 25-gallon or, on certain models, a 55-gallon application system. The system mounts to the tongue of the baler and holds enough preservative to treat 30 to 60 tons of hay. Depending on your need, choose the new 300 series automatic system, a 700 series commercial automatic system, an electronic system, or an economical manual control system (available in 25-gallon only).

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Moisture Sensors for Round Balers


Automatic systems for round balers are equipped with two moisture sensing discs, one mounted on each of the baler side walls, sensing moisture across the width of the bale via conductivity. The sensors can accurately read crop moisture from 8% to 60%, covering a wide range of moisture levels.

Product Specs

All applicators come as complete kits designed to fit your specific baler, and consist of 25 or 55 gallon tank

  • 12 volt pumping system
  • All plumbing and wiring supplied
  • Your choice of control options



H2O Precision Moisture Only System

Whether you bale dry hay or high moisture silage round bales, knowing your exact moisture while baling can help you to produce a consistent and high quality crop needed for  your operation. Round baler operators know that moisture variations are a challenge, and being able to accurately determine and monitor your hay moisture is an important key to success.

The H2O Precision Moisture Sensor is the perfect addition to your round baler to identify hay moisture variations in the windrow while baling, and is designed for the operators who demand the accuracy of the on-board moisture sensors, but do not need a full preservative applicator.

H2O Precision Moisture Sensor!



Dye Marker Kit for the H2O Precision Moisture Sensor

The optional Dye Marker Accessory can be added to the H2O Moisture Sensor that will mark every bale that is above a set moisture with a red, food-grade stripe. The bale is marked as it leaves the chamber, allowing the operator to easily identify those bales that are above their own moisture threshold. The food-grade dye mixes with water and applies up to 60 bales.

The Dye Marker Accessory consists of a tank, pump, end of bale sensor kit (200FCA), harness, and mounts on the baler.  The spray option can be

activated by selecting the feature in the H2O App and simply setting the moisture threshold you want to identify. See more on the H2O System & Dye Marker!

Click the link to see more info on the available control options or use the helpful chart below:

Control Options for Round Balers

Comparison of Applicator Controls

Electronic Applicator 300 Series Automatic 700 Series Automatic
Single Pump System X X X
Control Box with Adjustable Dial X
iPad Display X X
ISOBUS Display X
Built-in Flowmeter X X
Automatic Application X X
Moisture Sensing Capability X X
Job Records by Field X X
Job Records by Individual Bales X
Calculates Baling Rate: Round Baler X
Export Job Records to iPad X
Hay Indicator Compatible X X X
Stroke Counter on Small Square Baler X
Dye Sprayer Kit Compatible: Small Square Baler, Large Square Baler X

700 Series Automatic Control System

The 700 Automatic Applicator is the choice of applicator for the round or small square operator that makes hay commercially or is looking for the added performance and capabilities of the 700 system.

The 700 system on round balers reads moisture with two discs in the bale chamber up to 70% moisture, and also has a sensor on the bale door to record individual bale records. Both systems have the ability to store and download job and individual bale records via USB and export via iPad. The system can be controlled one of two ways:

  1. If the operator has an ISOBUS tractor with a VT display and is not using it to control the baler, the applicator functions can be viewed through the tractor display.
  2. If the first option is not available to the operator, the hardwired receiver is available to allow the customer to operate the applicator through their own iPad.


300 Series Automatic Control System


The 300 series automatic control system is a more compact and efficient applicator that accurately senses moisture on the go and adjusts the application of preservative to match the condition of the hay. This precision give the operator the exact amount of product required to keep their crop in great condition, without wasting product. The 300 Series applicator is controlled with an iPad* through a Bluetooth receiver, eliminating harnesses in the cab.

New improvements to the 300 Series Automatic Applicator include:

  • Single constant-pressure pump with pulsing solenoid that reacts quickly to changes in application rates
  • Improved flowmeter that works on a range of products
  • Smaller and more compact system that is easier to install and maintain

The applicator takes moisture and baling rate information from the two star wheel sensors on small square balers, and two moisture discs in the bale chamber on round balers, and the system will automatically apply the correct amount of product. The moisture, tonnage, and rates are all displayed on the screen, along with the volume used. A simple push of any Main Menu key pulls up a selection of other screens including adjustable settings and a Job Records screen. The system stores 63 jobs by date and time, number of tons baled, product used, and high and average moisture.

*iPad Mini or iPad 3rd Generation (2012) or newer, running the current iOS operating system or one previous version required for iPad option

Electronic Control Systems

electric_controlsThe electronic cab control is a solid state electronic pump control used for large round and large square balers. The control is mounted in the cab or on the fender. Application rate is quickly and easily adjusted from the operator s seat. Once set, the electronic control will hold the application rate constant. This unit is included with all 25-and 55-gallon applicators with electronic control. It is also included with 100-gallon applicators with electronic control for large square balers.

Manual Control Systems

manual_controlsThe manual pressure regulator provides full-rate adjustment at the applicator. This economical control is available for 25-gallon applicators only.

Your hay is important. Make sure your preservative does what it says it will.

Find out more >>

Hay Indicator (Crop Eyes)


The hay indicator sensors see when hay enters the balers pick-up and activates the preservative application. When no crop is coming into the baler, the system will pause on its own, while being ready to apply when crop once again enters the baler.

Part# 474A - Pre-700 Series Automatic Applicator & Electronic Systems

Part #474C - 700 Series Automatic Applicator

H2O Precision Moisture Sensor


The H2O Precision Moisture Sensor is a new moisture option for Small Square, Round and Large Square balers. Two discs or star wheels mount in the bale chamber and read moisture with the patented side-to-side technology. Allowing accurate readings up to 60% moisture on the round and large square balers, and up to 33% on small squares.

The H2O Precision Moisture Sensor is controlled with your Apple or Android smart phone or tablet via a hardwired connection and free app.

Part# 201RB - Round Balers

Part# 201SS - Small Square Balers

Part# 201LS - Large Square Balers


Floor-Mounted Applicator Pause Switch


Part# 475

The floor-mounted applicator pause switch is an inexpensive addition to your application system the enables the operator to easily stop and start the applicator. For use with any automatic application system, 2005 and newer.


Transfer Pumps


To transfer Baler’s Choice Hay Preservative safely and easily from your storage container to your applicator tank, use any of the following transfer pumps:

Model 9214: For a rapid transfer rate of 14 gallons per minute, this 12-volt unit can get the job done quickly.

Model 9212: This standard output, 12-volt model, will transfer preservative at a rate of 4 gallons per minute.

Model 9213: This inexpensive hand transfer pump is ideal for transferring small amounts of preservative easily.


Flow Meter


Part# 453

Digital Electronic Flow Meter is for use with any Harvest Tec preservative applicator delivering between 40 and 500 pounds per hour. The flow meter reads the application rate in pounds per hour and total pounds used.


Dye Sprayer Marking System


The Dye Sprayer Marking System is a simple way to visibly mark the wet areas on your large square bales. Compatible with the 600 & 700 Series Automatic Applicator or moisture only system for any large square baler. The 3-gallon system is mounted near the bale chamber and when the adjustable high moisture alarm sounds, the system will spray a red-colored, food-grade dye on the exact location on the bale for a quick and easy reference.

Part# 030-0840 - 600 Series

Part# 030-0740 - 700 Series


GPS Interface Kit


By incorporating the GPS into the Model 600 or 700 system the producer has the ability to create yield maps for their crops, allowing them to gain the knowledge needed to maximize productivity. The kit consists of a removable data storage card and GPS interface harness that is compatible with the Trimble 162 AgGPS, which is purchased separately from a Trimble dealer.

Part# 030-0780GPS - 700 Series

Part# 030-0880GPS - 600 Series

Automatic Applicator kits DO NOT include display

Made for iPad® running the current iOS operating system
or one version previous is required for iPad operation
*iPad is a trademark of Apple Inc., registered in the U.S. and other countries.

*Contact Your Local Vermeer Dealer For Pricing*


Baler Model 300 Series
Automatic Applicator
Electronic Control Applicator Manual Applicator Upgrade to 300 Automatic
504, 604 Series 2 Pro 331 431 N/A N/A
504, 505 J,K,M,N Series 3464484C 4414484 4394484 3U64484C
Rebel Series 3464484C 4414484 4394484 3U64484C
XL Series 3464484C 4414484 4394484 3U64484C


Baler Model 700 Series Automatic Applicator 300 Series Automatic Applicator Electronic Applicator Applicator Upgrade to 300 Automatic
404, 504 Pro Series 1 7494523C 3494523B 4484523 3U94523C
604 Series 3 Pro 7494543C 3494543C 4484543 N/A
604M, 605M, 604N, 605N 7494505C 3494505B 4484505 3U94505C
ZR5 Self-Propelled Baler 735Z 335Z 445Z N/A


Baler Style Moisture Only Upgrade to Auto Applicator
Round Baler 201RB (H2O Kit) N/A
030-300RB Contact Harvest Tec


Description Part Number
400 Series iPad Conversion Kit (Bluetooth receiver) 030-4672B
600 Series iPad Conversion Kit (Bluetooth receiver) 030-6672C
iPad Mini Mounting Kit 030-2012MK
iPad Mini & Mounting Kit Combo (iPad Mini, mount, charger) 030-2670DK
Baler Mounted Moisture Tester 008-FX2000
200 Series Moisture Only Dye Marker 200DM
Hay Indicators (Crop-Eyes) 030-474A
12V Electronic Transfer Pump (4 Gal/Min) 008-9212
12V Electronic Transfer Pump (15 Gal/Min) 008-9214
110V Electronic Transfer Pump (4 Gal/Min) 008-9215