"This third season has been quite different," Mr Boom said however.
"Very wet conditions during winter/spring 2017 really challenged the pasture-only and cropping farms, while the PKE farm sailed through without too much problem. Very soft soils that had been cropped the previous season are a struggle during a wet winter/spring like we had. The cropping farm had to cull some cows early to get through."
The financial results of the three farms would be presented next week.
"The NARF trial work has been a real eye-opener for many," Mr Boom added.
"When you average the last three years, the pasture-only farm was not far behind the PKE farm in profit. There are a lot of hidden costs associated with increasing production through putting more feed into the system. This project has allowed us to put some numbers on these less tangible costs."
Next week's Farm Systems for Profit field day starts at 10am on Thursday on the Northland Agricultural Research Farm, 531 State Highway 12, just north of Dargaville.
Presentations will be followed by a farm walk and light lunch. All welcome, no cost, no RSVP required.
For more information or to subscribe to fortnightly email updates, go to www.nddt.nz