Nutrient Cycle Information
Knowing the amount of nutrients produced on your farm can help you to better utilize this valuable resource to improve food crop production and preserve and protect natural resources.
Example: A small village piggery has 3 sows, 1 boar, 1 replacement gilt, 5 nursery pigs, and 10 grower pigs. To calculate the annual nutrients produced on the farm, you will need to estimate the weight of each class of livestock.
Example: A small village piggery has 3 sows, 1 boar, 1 replacement gilt, 5 nursery pigs, and 10 grower pigs. To calculate the annual nutrients produced on the farm, you will need to estimate the weight of each class of livestock.
Formula: number of animals × average weight (pounds) = total weight (pounds)
Sows 3 × 200 = 600 Boars 1 × 300 = 300 Replacement gilts 1 × 150 = 150 Nursery pigs (< 40 lb) 5 × 25 = 125 Grower pigs 10 × 80 = 800 Total weight 1975 1975 ÷ 1000 = 1.975 livestock equivalents |
For each livestock equivalent, multiply by the factor below to find nutrients produced per year
Formula: factor × livestock equivalent = amount per year for the example above Annual weight, tons 9.1a × 1.975 = 18.0 tons Annual volume, cubic yards 10.8b × 1.975 = 21.3 cu yd Nitrogen (N), pounds 138.7c × 1.975 = 274 lb/yr N Phosphorus (P), pounds 51.1c × 1.975 = 101 lb/yr P Potassium (K), pounds 80.3c × 1.975 = 159 lb/yr K |
a The weight is based on an estimate of 50 pounds manure produced per day per 1000 pounds of livestock: 50 pounds/day × 365 days/year = 18,250 pounds/yr; 18,250 pounds/yr ÷ 2000 pounds/ton = 9.1 tons/yr
b The volume is based on an estimate of 0.80 cubic feet per day per 1000 pounds of livestock: 0.8 cu ft/day × 365 days/year = 292 cu ft/yr; 292 cu ft/yr ÷ 27 cu ft/cu yd = 10.8 cu yd/yr
c Nutrients are based on the following estimates of pounds per day per 1000 pounds of livestock: N = 0.38, P = 0.14, K = 0.22. For example, 0.38 lb/day N x 365 = 138.7 lb/yr N
b The volume is based on an estimate of 0.80 cubic feet per day per 1000 pounds of livestock: 0.8 cu ft/day × 365 days/year = 292 cu ft/yr; 292 cu ft/yr ÷ 27 cu ft/cu yd = 10.8 cu yd/yr
c Nutrients are based on the following estimates of pounds per day per 1000 pounds of livestock: N = 0.38, P = 0.14, K = 0.22. For example, 0.38 lb/day N x 365 = 138.7 lb/yr N
Your nutrient cycle calculation: number of animals × average weight (pounds) = total weight (pounds)
Sows __________ × __________ = __________
Boars __________ × __________ = __________
Replacement gilts __________ × __________ = __________
Nursery pigs, < 40 lb __________ × __________ = __________
Grower pigs __________ × __________ = __________
Total weight = ___________
Total weight ÷ 1000 = livestock equivalent = ___________
To find your annual production, substitute your livestock equivalent in the following calculations.
Factor Equivalent Annual amount
Annual weight, tons 9.1 × __________ = __________
Annual volume, cu yd 10.8 × __________ = __________
Nitrogen (N), pounds 138.7 × __________ = __________
Phosphorus (P), pounds 51.1 × __________ = __________
Potassium (K), pounds 80.3 × __________ = __________
Sows __________ × __________ = __________
Boars __________ × __________ = __________
Replacement gilts __________ × __________ = __________
Nursery pigs, < 40 lb __________ × __________ = __________
Grower pigs __________ × __________ = __________
Total weight = ___________
Total weight ÷ 1000 = livestock equivalent = ___________
To find your annual production, substitute your livestock equivalent in the following calculations.
Factor Equivalent Annual amount
Annual weight, tons 9.1 × __________ = __________
Annual volume, cu yd 10.8 × __________ = __________
Nitrogen (N), pounds 138.7 × __________ = __________
Phosphorus (P), pounds 51.1 × __________ = __________
Potassium (K), pounds 80.3 × __________ = __________
This information was used with permission from the following publication:
Fukumoto, G, C. Evensen, and L. Castro, 2008. Livestock Producer’s Nutrient Management Planner Guidebook: A Waste Management Planning Guide for Pacific Island Livestock Producers. University of Hawaii, Cooperative Extension Service, AWM-4. 16 pp. www.ctahr. hawaii.edu/oc/freepubs/pdf/AWM-4.pdf.