Like I've said many times; "to everything there is a specific frequency that excites its molecules best". To gain the best bang for the buck. That does not mean other frequencies do not excite the material's molecules within range.
As far as the combination of herbaceous materials processed the microwave range is similarly close and the results would be too close to considering a variation. So the same machine can be used for all herbaceous materials.
Oh I almost forgot "'pulverization' into powder form and controlled mixing" is not necessary and in fact the typical farm machine that makes silage is quite adequate and even that kind of reduction is not necessary.