154 EXPERIMENTS WITH PLANTS 



Lay out six beds a yard square; 1 in each bed place 

 a different fertilizer, working it well into the soil 

 with a spade. The amount to be used may be deter- 

 mined by finding the amount used per acre in practice 

 and dividing this by 4,840 (the number of square yards 

 per acre). The following will give an approximate 

 idea of these amounts: 



Lbs. per acre. Lbs. per square yard. 



(a) Stable manure .... 5,000 to 8,000 ... 1 to 1% 

 (&) Chili saltpeter .... 200 to 300 ... A to & 



(c) Superphosphate .... 200 to 300 ... <h to -&- 



(d) Wood ashes 1,500 to 2,500 . . % to X 



(e) Quicklime 8,000 to 20,000 . . . \% to 4 



The wood ashes used should be unleached ashes 

 from cordwood (i. e., ordinary wood-stove ashes), in 

 which case they contain about one pound of potashes 

 in twelve of ashes: the rest consists chiefly of lime. 

 If we wish to add potash without lime we may use 

 commercial potashes, saleratus or pearl-ash at the rate 

 of one thirty- sixth to one twenty-fourth pound per 

 square yard: this should be dissolved in two or three 

 gallons of water and applied in liquid form. 



Inasmuch as the amount needed varies greatly with 

 the character of the soil, it would be desirable to make 

 a parallel series of three beds for each kind of ferti- 

 lizer, using on one only half the amount given above, 

 on another the given amount, and on the third half as 

 much again as the given amount. In case there seems 



1 These should be separated from each other by an interval of several feet, 

 to prevent the applied fertilizer from diffusing from one plot to another. 



