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 lesults concerning profits: 



Fertilizers 



Cost 

 per acre 



Net \alue of mciease 

 per acre per rotation 



Per cent piofit on cost 

 of fertilizer 



A 

 B 



$4 00 



8 00 



S15 00 

 2160 



375 

 270 



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 expand for feitihzers. 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 vnth. fertiUzer '^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 Amoimt 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 "law 

 of the minimum" and the ^Maw of diminishing returns." 



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

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

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

 limited hy the amount of that particular element contained in the 



