This guide is mainly based on info from the Gnomoria wiki and forum (all of which is probably outdated) and my own dodgy math, so take it with a grain of salt. Based on v0.9.14. I'll try to do independent research to verify / fix the info in this guide.

Please note that these numbers do not include the time to pick and replant, as that's a function of the gnome's skill. Therefore, the amount you need for your world will vary between each pair of numbers. When in doubt, be more conservative.

Plants - Harvests per Year (Whole Harvests)

Trees - 4.95 (4)
Wheat - 6.60 (6)
Strawberry/Grape - 8.80 (8)
Cotton/Apple/Orange - 9.90 (9)

Animals - Plots per Animal to Feed (Less conservative) - based on 100 Fitness animals

Yak / Alpaca

• 10.7 (9.7) Wheat

Emu (assuming all seeds drop at the same rate)

• 14.2 (12.93) Wheat
  
• 10.7 (9.7) Strawberry / Grape
  
• 9.5 (8.62) Cotton

After doing some preliminary testing, as of this version, the sunlight time to grow is correct from the wiki.

Cotton/Tree Fruit takes 48 hours ± 5 hours.
Strawberry/Grape takes 54 hours ± 5 hours. (Grapes were not specifically tested)
Wheat takes 72 hours ± 8 hours
Trees take 92 hours ± ? (I quit testing at this point)

Mushrooms have not been tested yet.

It should be noted that the time variance seems to follow a uniform distribution.

Although I couldn't figure out a good test method, yaks seem to produce 8 milk every 48 hours. This would be difficult to test outside of a dedicated setup since you only know if a yak needs to be milked when the 'Tend animal' job gets queued.

The grow times only include time from sunrise to sundown.
I found evidence of, at least, predawn light. Several test units and grass grew before sunrise. This time is not included in the grow times, but Spring Day 6 has at least 15 minutes of this light and Spring Day 7 has at the very least 20 minutes.
I have not found evidence of postdusk light, other than it being inferred from RoboBob stating Spring Day 6 should be 12 hours long. Normally, it lasts 11h 31m (6:14-17:45), but with the addition of the 15 minutes of predawn light, one could reason that there's 15 minutes of postdusk light. More testing is required before conclusions can be made.
I've come to the conclusion that the predawn light is irrelevant. From my observations, while you do get 'extra' grow time before dawn, the light also ends before sundown - about the same amount of time as you gain in the morning. Effectively, you get the amount of time that's indicated by sunrise and sundown, just shifted by about 35 minutes. This may be an issue on my end (being in year 9) or in Gnomoria itself.

With that being the case, the total agricultural light per year would be 475 hours and 55 minutes.

Testing in progress: Preliminary tests indicate Grapes seem to spawn an extra seed ~80% of the time. Low sample count prevents this from being definitive. Conservative estimate at 75%.
Continued, but incomplete testing, indicate that for Grapes, extra seeds seem to spawn ~76% of the time, with the conservative estimate at 70%. While I'm relatively certain that the true number is 75%, at the moment my data indicates it is 76% ± 5.1%.

Preliminary data indicates Yaks eat ~1.4 Straw per day, but there is a distinct lack of data. The individual Yak's fitness may play a role, with higher Fitness resulting in less consumed. Conservative estimate of 1.45 / day.
After recording a few samples, I have come to a very, very hypothetical equation: Animals consume 64 - ((Fitness - 100) / 1.625) units of food per year. More testing is required to confirm, but as a conservative estimate plug in your lowest fitness animal and multiple by the number of livestock.

Always remember to have a small surplus at hand, in case of bad RNG or calculations.

Agriculture only advances in daylight, except in winter, so we have to calculate the total amount of day light in the year. We know that at Summer and Winter solstice (Day 6) the amount of daylight is about 16 and 8 hours, respectively, while at the equinoxes (Spring and Fall Day 6) there is 12 hours of day light.

The average daylight during Spring and Fall is therefore about 12 hour/day; combined that comes to 288 hours. (12 Days * 12 hours * 2 seasons)

Winter is useless, so onto summer. I'm not exactly certain how to do this math correctly, please comment if I've done this incorrectly - I never exactly aced Trig.

The amount of sunlight per season can be boiled down to a wave - and therefore a circle - with the radius being 4 hours (1 daylight difference factor) on the y-axis and 12 days (1 season) on the x-axis. The wave crest is Summer Day 6, while the trough is Winter Day 6. That means summer lasts from (-0.5,y) to (0.5,y) thus the average summer daylight deviation would be at (-0.25,y) and (0.25,y).

Therefore, the total hours of daylight in summer equal the ((average daylight deviation factor * 4 hours) + 12 hours baseline) * 12 days.

ADDF = sin (cos⁻¹ (0.25)) ≈ 0.9682
ADDF * 4 hours ≈ 3.8729 hours + 12 hours / day ≈ 15.8729 hours / day
15.8729 hours / day * 12 days ≈ 190.48 hours

So the total agricultural daylight in a year is about 478.48 hours / year. Nearly 40% of your total agricultural daylight is in Summer, in other words, you get about 33% more light in Summer than Spring or Fall. Obviously, the daylight time in game doesn't follow a smooth curve, but is laddered, so I'll be assuming for calculation that there are 478 daylight hours in a year.

The true agricultural light per year comes to 475 hours and 55 minutes, broken down as follows: 141 hours 13 minutes of Spring, 187 hours 55 minutes of Summer and 146 hours 47 minutes of Fall/Autumn. I'll be using 475 hours for calculations.

The rest of the info is from the wiki and may be incorrect. More testing may be required.
Average daylight time to grow:
Trees - 96 hours
Wheat - 72 hours
Strawberry/Grape - 54 hours
Cotton/Apple/Orange - 48 hours

Therefore, you'll get this many harvests / year, disregarding labor times - which are substantial.
Trees - 4.95 (4)
Wheat - 6.60 (6)
Strawberry/Grape - 8.80 (8)
Cotton/Apple/Orange - 9.90 (9)

Each animal eats ~64 ± 6 food units/year (based on 100 ± 10 fitness).

To feed animals, you're need at least (very conservatively - assumes 0 stocked food and only gaining 1 of the respective feed / plot):

Yak/Alpaca - 64 / 6 = 10.7 wheat plots / animal

Less conservatively (Year 2+):
Yak/Alpaca - 64 / 6.60 = 9.7 wheat plots / animal

For emu's specifically, there is a significant chance to drop 2 seed when wheat/cotton/strawberry/grape plots are harvested. For Grapes, I've tested ~75%. This excess would be your feed (so that the the plots could get replanted).

(Assuming seeds drop at the same rate for all plants):
Emu - (64 / 6) * (4 / 3) = 14.2 wheat plots / animal OR
Emu - (64 / 8) * (4 / 3) = 10.7 strawberry/grape plots / animal OR
Emu - (64 / 9) * (4 / 3) = 9.5 cotton plots / animal
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A gnome goes from 100 Hunger to 0 Hunger in 3 days, looks for food at 75 Hunger and stops working at 50 Hunger. At 0 Hunger, the gnome dies. Thus 25 Hunger is about 18 hours of a gnome's life. Given that information, every food item effectively extends a gnome's life for a certain amount of time. All values calculated are from average quality; meat, mushrooms, fruits and eggs are always average quality. Quality directly impacts Hunger: Poor (x0.9), Average (x1), Fine (x2), Superior (x3), Masterful (x5), Legendary (x10). The Δ refers to the difference of a crafted item's Hunger from its component parts.

Time is derived from Hunger/25 * 18 hours.

Meat - 3.6 hours
Mushroom/Cheese - 7.2 hours
Fruit/Egg - 10.8 hours
Bread/Sausage - 14.4 hours (Sausage: Δ +10.8 hours)
Cheese Omelette - 18 hours (Δ +0 hours)
Mushroom Omelette - 25.2 hours (Δ +0 hours)
Sausage Omelette - 32.4 hours (Δ +0 hours)
Sandwich - 36 hours (Δ +10 hours)

A similar system works for Thirst, however it fully drains in 1.5 days and they start looking for drinks at 84 Thirst. Water and Milk are always of average quality. The Δ refers to the amount of Hunger hours (Hhours) that would have been otherwise sated by the ingredients.

Time is derived from Thirst/25 * 9 hours.

Water - 3.6 hours
Milk - 9 hours
Tea - 9 hours (Δ 7.2 Hhours)
Wine - 18 hours (Δ 10.8 Hhours)
Beer - 18 hours (Δ 14.4 Hhours)

Note : this uses old calculations and is inaccurate as a result.

For brevity, Hh refers to Hunger hours while Th refers to Thirst hours.

A max efficiency yak pasture (13 yaks, 1 male, 12 females), produces 1 yak per day and 48 milk per day (12 females * 8 milk / 2 days). You need ~147 wheat plots to feed them in the year (13*11.3), which also produce an average of ~20 grain per day.

1 yak -> 12 meat (43.2 Hh) -> 12 sausages (172.8 Hh)
48 milk (432 Th) OR -> 48 cheese (345.1 Hh)
20 grain -> 20 bread (288 Hh) OR 20 beer (360 Th)
12 sandwiches can be made for (Δ 120 Hh)

Resulting in (ideally, if nothing else is produced): 576 Hh + 576 Th
From: 12 sandwiches, 8 Beer, 28 Milk & 20 Cheese

Which can support 24 gnomes, limited to 18 by food units (1 gnome/sandwich & 1 gnome/3 cheese) should they get hunger at the same time - unlikely, but possible.

In addition, Wheat produces excess seeds which can feed Emus, which can provide more meat and eggs - that isn't included due to lack of information on seed spawning, emu birthrates and egg spawn times.
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Sausage Omelettes should never be made, as the sausage is better spent in a sandwich. If they must, only Cheese Omelettes should be made and only to reduce the amount of food in stock - mostly useful for preventing / reducing mants.

Likewise, it's better to make wine over beer - as you lose less Hunger hours from crafting it.

Mushrooms have no particular advantage, other than variety. All mushrooms should be made into tea.

This guide was made in good faith and I take no responsibility for less than ideal results. However, I will totally take credit for ideal ones. As stated before, the info in this guide will be updated when possible. Comments and/or suggestions are welcome.