Yes and no. It’s possible to do Theurgic farming more sustainably than at present–but the science of it is poorly understood, because for so long the Hegemony has been enjoying a blood surplus that meant it could ignore the limitations of their current agriculture model with e.g. just a bit of crop rotation.
It will take either a whole lot more blood or many years of soil repair to fix the problem–and the solution needs to be done at a large scale to avoid starvation. You’ll also need a lot of landowners to convert from commercial cash cropping back to food.