I read lots about this plant and that plant being heavy feeders (tomato and garlic most notably) but I don't ever see that. Since I grow no pulses, I do occasionally add urea to my beds (maybe each bed got sprinkled once), and I always add some wood ash to keep them at a decent pH (and yes, to replenish K as well as other micronutrients), and of course most beds get two inches of various compostables every year. In fact the beds are entirely made of compost by now. But what do you really gain by, say, having 250 ppm of (any major nutrient) as opposed to 150 ppm?