Precision technology has been a buzz word in the ag industry for years and with ever-tightening regulations and low commodity prices, precision remains a forefront topic. Yet, this technology hasn’t been popular with dry fertilizer or dry manure applications. With that said, we see a lot of potential with scale-based rate control for dry applications moving forward.
Currently, dry spreading is accomplished by measuring a known volume coming out of the back of the spreader and converting it to weight (pounds per acre) by multiplying by a density pounds per cubic foot. While this is more common with dry fertilizer than dry manure, the opportunity for precision still exists. The challenge with manure is the constantly changing density. Even if the density of manure is calculated using an average, the manure can still change from load to load and even vary within the load.
As we are seeing more manure and dry fertilizer spreaders sold with scales, the ability to compare the actual amount of product spread versus the theoretical amount spread increases our application precision. Using scale based rate control allows for greater accuracy, especially in variable rate applications.
We currently offer two systems: Topcon’s Athene/Scale Link 2 platform and Raven’s RCM. Both are typical rate controller systems. They work by calculating the volume going out the back of the spreader based on the width and height of the spreader gate and an encoder telling the system how fast the floor is moving. The rate controller controls a hydraulic valve which speeds up or slows down the speed of the floor based on how fast the spreader is moving and the desired application rate.
When weigh bars are tied to the rate controller, the system can calculate how much has been spread over a given distance using scales versus how much theoretically should have been spread over that same distance. The rate controller then “recalibrates” itself to correct for the difference. This difference is caused by changes in product density. The Topcon system makes this calculation every five seconds, while Raven’s system will typically be set to calculate every ¹/20th of a load. The operator must have an estimated density when starting a new product, but after that, the rate controller does all the work. Both systems allow the operator to program a target rate per acre and the rate controller regulates the spreader floor speed to achieve this target. Both systems include clean-out modes allowing the spreader floor to be sped up as the spreader nears an empty state.
Currently, the Topcon Athene/Scale Link 2 will work for both dry manure and dry fertilizer, while the Raven RCM is for dry manure only. Both systems are ISOBUS compliant and require an ISOBUS Universal Terminal (UT) and ISOBUS connector in the tractor cab to operate. So far, we know that the systems will work with Raven Viper 4+/CR7, JD Greenstar, Topcon X Consoles, CNH/Trimble Pro 700 and Ag Leader. Some monitors may require a UT unlock and additional harnesses.
The advantages of using a scale based rate control system include more accurate record-keeping and map-making abilities. These advantages will continue to grow as more manure is custom spread and application regulations become greater for both manure and dry fertilizer. We are seeing several of our equipment suppliers
offer scale based systems as options and currently have several being utilized on Artex manure spreaders. We believe scale based systems will become increasingly popular for the future of dry application.