Farmland Assessment Tool for GIS users. 
We have developed a simple ArcMap (soon to be for ArcGIS Online & Pro) add on that will assist parcel managers with Farmland Assessment specifically in Illinois. And we're giving it away for free. 
Removing Roadblocks
The State requires and overlay of three separate layers for proper valuation and assessment: Parcels, Soils and Land Use.  It's a rather simple geoprocessing function of these layers that results in the required acreage calculation of each parcel polygon to be properly assessed