This is the payroll for the people who run the fief, which includes clerks, servants at your manor/chateau, town officials (plus what the towns and cities collect via the "town tax" for their own officials), game wardens and the like. These are the people that collect your taxes. If you spend less than 4 ducats per capita per season on officials, it will have an adverse effect on loyalty and taxes collected. Too little spent on officials will also increase graft, which comes out of YOUR tax revenues. Officials would average about 6,000 ducats a year, or 1,500 per season. This gives you several hundred officials on the payroll for this fief. The maximum you can spend is 4 ducats per capita per season.