Specific workable examples need systems and numbers we don't have. I can generalize. Land, labor, etc, matter. Abstraction required.
Needs (Very basic):Each person needs 1 food unit per day.
Approach 1: Project with inputs:Inputs/requirements:Land: +8 ( +4 Productiveness, +2 irrigation, +2 Fertilizer)
Labor: +7 (+3 Skill, +2 Tools, +2 Morale Bonus) (Assumes one person working only)
/Time: +15 Per turn
Outputs:End goal: produce 1000 food per field area.
Total Labor Requirement: 1000 (you can increase or decrease to reflect task / circumstance difficulty)
Total Time Requirement: 1 season (you can't pull this task off (harvest) more than once a growing season)
Assuming the above, this one person (w/skills & circumstances above) needs 66 2/3 turns working this field to get 1000 units of food (feeding about 2.7 for a year). Standardize your turn length (1 day/turn, or 4 hours/turn, whatever). If you want more food, add better mods like infrastructure or tools to boost the numbers, or employ more people (labor).
Random variable bonuses and penalties can be added like weather, etc. Better fields/climates may have more than one growing season (2 harvests, etc).
Also, a farm may have multiple fields. Meaning this person/farm could end up feeding far more than 1.7 other people (assuming all other things equal).
If a turn is 4 hours (6 turns a day, 2 for labor, 2 for leisure, 2 for sleep), that means 33 1/3 days of labor fills the quota for 1000 food.
If a turn is a day that means 66 2/3 days for the quota for 1000 units of food.
Remember Multiple fields on a farm being a thing? Assume this farm has 4 fields total:
4 hour turns: 133.2 days to labor in all 4 fields for 1000 units of food.
1 day turns: 266.4 days to labor in all 4 fields for 1000 units of food.
If the farmer has 4 fields producing 1000 units of food each, then that means this feeds 10.96 people for a year (4000/365) and is a pretty efficient system. Factor that into your population.... You need 91.24 farms like this to feed 1000 people. That's a better than 10 to 1 ratio of how many farmers/farms like this you need to support food need for a place (village/city/etc). Keeping in mind that building the farm and infrastructure also are tasks requiring labor, materials, etc. You end up with a pretty comprehensive system allowing for multiple variables to be taken into account. Of course, you could just say each farm produces X food and that feeds Y number of people, but no thanks.
The way this method works, you can basically keep a "character sheet" for the whole thing tucked away something like this:
TavenFields Farm: (Insert Region/District Name for location purposes)
Inputs/requirements:
Land: +8 ( +4 Productiveness, +2 irrigation, +2 Fertilizer)
Labor: +7 (+3 Skill, +2 Tools, +2 Morale Bonus) (Assumes one person working only)
/Time: +15 Per turn
Outputs:
End goal: produce 1000 food per field area.
Total Labor Requirement: 1000 (you can increase or decrease to reflect task / circumstance difficulty)
Total Time Requirement: 1 season (you can't pull this task off (harvest) more than once a growing season)
# of Fields: 4
Produces: 4000 Units of food.
Feeds 10.96 people/year