During planting and harvest most adults move to heavy labour for 4-8 weeks, and the extra food that needs is about 0.7 to 6.4 million kcal for a community of 100, which raises daily demand by roughly 9% to 41% in those weeks. Spring is the dangerous spike because it falls when stored food is lowest, so plan the extra into the stores before winter.
Part of Caloric Budget for a Community
Seasonal labour calorie spikes are the temporary rises in a community’s food energy need when most adults do heavy field work during planting and harvest.
The Annual Average Hides A Spring Peak
The caloric guide says that during peak agricultural seasons, planting in spring and harvest in fall, most adults shift into heavy labour for 4-8 weeks and that the budget must account for the spike. It gives three adult bands: moderate labour 2,600-3,000 kcal a day and heavy labour 3,500-4,500 kcal a day, for a community with 50-60 working adults. It does not give a number for the spike itself; the arithmetic below does, using only those figures.
Worked Example: How Big Is The Spike?
Extra energy per adult per day = heavy band − moderate band for the same person.
- Smallest gap: 3,500 − 3,000 = 500 kcal. Largest gap: 4,500 − 2,600 = 1,900 kcal. Midpoint: 4,000 − 2,800 = 1,200 kcal.
- Smallest total: 500 kcal × 28 days (4 weeks) × 50 adults = 700,000 kcal.
- Largest total: 1,900 kcal × 56 days (8 weeks) × 60 adults = 6,384,000 kcal.
- Middle case: 1,200 kcal × 42 days (6 weeks) × 55 adults = 2,772,000 kcal.
- As a share of the year’s 102.2 million kcal: 700,000 ÷ 102.2 million = 0.7%; 6,384,000 ÷ 102.2 million = 6.2%; the middle case is 2.7%.
- Daily demand in the peak weeks: 50 × 500 = 25,000 kcal extra, or 25,000 ÷ 280,000 = 8.9% (about 9%) more than the 280,000 kcal baseline day; 60 × 1,900 = 114,000 kcal, or 40.7% (about 41%) more. The middle case is 55 × 1,200 = 66,000, or 23.6% more.
These figures take the parent’s labour bands as given. For women the heavy band is probably too high (Adult Caloric Needs by Activity Level), so the spike for a mixed workforce may be smaller than this arithmetic, and it is also reduced by children and the elderly who do not do heavy work.
When The Spike Lands
The parent’s monthly breakdown puts spring at the point where stored crops are dwindling and only early greens are coming in, while fall is the peak harvest. So the autumn spike is paid out of abundance, and the spring spike out of the last of the winter stores. The 4-8-week spring labour requirement of 0.7-6.4 million kcal equals 1.7%-15% of the 42 million kcal winter store the parent says a community of 100 should hold (700,000 ÷ 42 million = 1.7%; 6,384,000 ÷ 42 million = 15.2%).
Method: Plan For The Spike
Step 1: List the weeks of heavy labour from the community’s planting and harvest calendar (Harvest Labor Calendar). Step 2: Count the adults who will be on heavy work, by sex. Step 3: Compute the extra using the band difference above, or your own measured figures. Step 4: Add the total to the stores plan, or reserve it from the winter store for spring. Step 5: Feed heavy workers first and in addition, not by taking from children and the elderly (Children, Pregnant, and Elderly Adjustments).
Common Mistakes
- Treating the spike as an average. A 6-week 24% rise is not visible in an annual figure but empties a store.
- Forgetting that labour shortage and calorie shortage meet. The weeks when everyone is hungriest are the weeks nobody has time for the kitchen (Surge Labor).
- Planning only for autumn. Spring planting is the heavier draw on stores.
Safety
Heat, hard work and too little food
Heavy field work on an inadequate ration produces exhaustion, injury and illness, and hot weather adds heat injury. Give heavy workers extra food and water, rest breaks and shade, and watch for weight loss (Environmental Injuries).
What’s Next
- Learn next: Winter Calorie Gap Planning — where the spring spike is paid for
- Combine with: Planting and Harvest Windows — when the spikes fall