gjrich@iinet.net.au wrote:How do I convert bags, bushels, tonnes - per acre , hectere for wheat ,barley oats etc.
The Answer to this problem, like most of the others, can be found using unit analysis.
We can easily convert Acres to Hectares. There are 0.4047 hectares in one acre. So:
- Code: Select all
Bushel | 1 acre
-------------------------
Acre | 0.4047 Hectare
Notice that acres on the top of the equation (the numerator) and acres on the bottom (the divisor). SInce anything divided by itself is one, the units cancel out.
1 bushel per acre is equal to 1 bushel per 0.4047 Hectare
The largest headache in this problem lies in converting a bushel (a unit of volume) to a metric ton (a unit of mass). We convert volume to weight (and vice versa) by using a constant called the specific gravity, or in the case of things that can have void space (air space between the objects,) Bulk Density.
The weight of a bushel of a few selcted grains are:
1 bu. Wheat = 60 lbs
1 bu. Soybeans = 60 lbs
1 bu. Corn = 56 lbs
1 bu. Barley = 48 lbs.
Let's use Wheat/Soybeans, at 60 lb/bushel
- Code: Select all
Bushel | 1 acre | 60 lb |
--------------------------------------------
Acre | 0.4047 Hectare | bushel |
This tells us there are 148.26 pounds per hectare in every bushel per acre. But we want to get to meteric tons per hectrare. Knowing that there are 0.4536 kilograms per pound, and 1,000 kilograms per metric ton, we can continue...
- Code: Select all
Bushel | 1 acre | 60 lb | 0.4536 kg | ton |
------------------------------------------------------------
Acre | 0.4047 Hectare | bushel | lb | 1,000 kg |
Canceling units and multiplying this out gives us: 0.06725 metric tons per hectare
Therefore, to convert bushels/acre of wheat or Soybeans to metric tons per hectare, multiply by 0.6725.
To work this for other grains, insert the weight of the grain per bushel into the above formula and turn the crank.
William J. Knight
Health Physicist
Los Alamos National Labs