Edible protein per unit area of land
Edible protein per unit area of land is a measure of agricultural productivity. This measure for various major foodstuffs is shown in the chart below. Values are expressed for one calendar year. Biological values and usable protein values have been added to the chart to show the true relative value of each foodstock for human consumption. Usable protein values are determined by the biological value (BV) of each foodstuff and represent the amount of protein that is fully digested by humans, it is calculated as follows:
Soybeans produce at least two times more usable protein per unit area than any other major vegetable or grain crop, except for hemp which can produce up to 33 g/m2 (290 lb/acre). They produce 5 to 10 times more protein per unit area than land set aside for grazing animals to make milk, and up to 15 times more protein per unit area than land set aside for meat production.
|Edible protein (g/m²)||Edible protein (lb/acre)||BV (%)||Usable protein (g/m²)||Usable protein (lb/acre)||Limiting amino acid|
|Milk||9.2||82||91||8.4||75||methionine or cysteine|
|Beef||2.2||20||78||1.72||15.6||phenylalanine or tyrosine|
Selected averages as computed in the 1970s.