In one ton the whole value would be twenty times this or $23.40.  Add to this $8, which is about the average charge for mixing, bagging, shipping, selling and profit, and we find that $32 is probably the lowest figure at which this fertilizer could be purchased on the markets, and very likely the price would be higher as we have taken the lowest guaranteed per cent. of plant food for our basis of calculation.

Fertilizers are generally mixed and sold to the farmer on the ton basis.

LOW GRADE MIXTURES

Most dealers, to meet a certain demand, furnish mixtures ranging from $15 to $25 per ton.  These mixtures are necessarily low grade and are more expensive than the higher priced high grade mixtures.

For example: 

A certain potato fertilizer on the market, which we will call mixture
A, has the following guaranteed analysis: 

Ammonia 7 to 8 per cent. 
Available Phosphoric Acid 6 to 7 "
Actual Potash 5 to 6 "

A ton of this would contain: 

Pounds. 
Nitrogen                   115.4 value at 171/2c      $20.19
Available Phosphoric Acid  120     "    "  4c         4.80
Potash                     100     "    "  5c         5.00
-----                    ------
Totals                   335.4                    $29.99

Add to this the average charge for mixing, bagging, selling, profit, etc., $8, and the cost will be $37.99.

The selling price of this fertilizer would probably be not less than $40.  Now suppose the farmer thinks this a high priced and expensive fertilizer and looks about for something cheaper.  He finds a low grade potato fertilizer, which we will call mixture B, that has the following guarantee: 

Ammonia 31/2 to 4 per cent. 
Available Phosphoric Acid 3 to 31/2 "
Actual Potash 21/2 to 3 "

Just one-half the guarantee of the high grade mixture A. A ton of this contains: 

Pounds. 
Nitrogen 57.7 value at 171/2c $10.10 Available Phosphoric Acid 60 " " 4c 2.40 Potash 50 " " 5c 2.50
----- ------
Totals 167.7 $15.00
Add average charge for mixing, etc. 8.00
------
$23.00

The selling price of this would very likely be not less than $25.

This seems at first sight to be cheaper and more reasonable.  But let us see.

In a ton of mixture A he gets 335.4 pounds of plant food for $40, or at an average cost of twelve cents per pound, while in a ton of mixture B he gets 167.7 pounds of plant food for $25, or at an average cost of fifteen cents per pound.

To put it another way, in a ton of the high grade mixture A, he gets 335.4 pounds of plant food for $40.  To get the same amount of plant food, 335.4 pounds, in the low grade mixture, B, it will be necessary to buy two tons at a cost of $50.