6 77 



the same si/e, say about one-tenth of an acre, and may be either 



square or rectangular. A small path divides each plot, and a stake 

 must be plaeed at eaeh corner of the several plots to mark their 

 boundaries. The following is a plan of the blocks : 



I) 



i to 5 are sown with wheat. Xo. i gets no manure ; No. 2, a 

 complete wheat manure ; Xo. 3, the same manure as Xo. 2, with 

 potash left out ; Xo. 4, the same manure as No. 2, with nitrogen 

 left out ; Xo. 5, the same manure as Xo. 2, with phosphoric 

 acid left out. In each of these plots the straw and grain are to be 

 weighed separately. 



A to E are planted with potatoes. E gets no manure ; D gets 

 a complete potato manure ; C, the same manure as D, with the 

 exception of phosphoric acid ; B, the same manure as D, with the 

 exception of potash ; A, the same manure as D, with the exception 

 of nitrogen. 



In the case of the wheat plots, Xos. i to 5, if the soil required 

 no manure, then Xo. i would be as good, or nearly so, as Xos. 2, 

 3, 4 and 5 ; but if the soil needed manure then Xo. 2 would be 

 much better than Xo. i. If 2 was much better than 3, 4 or 5, then 

 a complete manure was required. If either 3, 4 or 5 was as good 

 as 2, that part of the complete manure was not required and could 

 be left out. 



In the case of the potatoes the same reasoning will apply to 

 them as to the wheat, but the results may not come out the same. 

 The wheat might show enough of potash and the potatoes a 

 deficiency, then the surface w r as short of potash, while there w r as 

 enough at a depth, or in the subsoil. Or the potatoes might show 

 a good supply of phosphoric acid, while the wheat was deficient, 

 showing that there was not enough for deep-rooted crops. Some- 

 thing of the same kind might happen with the nitrogen. 



After the exact condition of the soil is known, then you are in 

 a position to say what manure should be used for any given crop. 

 After the crop has been gathered and weight is known, then, by 

 reckoning from the table of the ash of different crops given under 



