THE LAW OF THE MINIMUM 373 



An Illustration. On a certain soil two different fertilizers were 

 tried the applications being made once in a three-year rotation. 

 The following are the three-year results concerning profits: 



It is to be noted that the fertilizer "A" gave a net return of 

 $15.00 per acre, or 375 per cent profit on the cost of fertilizer; 

 and "B" gave a net return of $21.60 per acre, which is 270 per 

 cent profit on the cost of the fertilizer. The fertilizer which gave 

 a net profit of 270 per cent returned $6.60 more per acre than 

 the fertilizer which gave a net return of 375 per cent on cost 

 of fertilizer. 



Suppose a man had fifty acres of similar land and had only 

 $200 of ready money to expend for fertilizers. He would be a poor 

 business man, indeed, if he could not see that if he borrowed $200 

 one year to enable him to fertilize every acre with fertilizer "B," 

 he could realize $330 more net profits, and in so doing realize at 

 least 165 per cent profit on the money borrowed. 



When such conditions prevail as regards the use of fertilizers 

 the land owner must first determine whether or not the change in 

 method of crop production will reduce the number of acres he can 

 raise, since the goal in profitable farming is " greatest amount of 

 profits per man." If the method of fertilization does not reduce 

 the number of acres of crop he can raise under his system of farm- 

 ing, then both fertilizers (A and B) would be profitable and the 

 one which gives the greater net profits (dollars) per acre is the 

 more profitable. 



Proper Kind and Amount of Fertilizers. Two important 

 factors come into play in determining the profitable use of com- 

 mercial fertilizers, namely, the proper kind of fertilizers and the 

 right amounts that should be used. These two factors may be 

 expressed in terms of two economic laws, as follows: The "lav 

 of the minimum" and the "law of diminishing returns." 



The law of the minimum as related to fertilizers and crop pro- 

 duction may be stated as follows: // the soil is deficient in one 

 particular element of plant-food, the yield of a given crop will be 

 limited by the amount of that particular element contained in the 



