THE USE OF MANURES 169 



more, if information is wanted with regard 

 to the actual quantities of these substances 

 that should be employed per acre, one would 

 proceed on some such scheme as this : 



Plot 1. No manure. 



Plot 2. 5 cwt. super., 1 cwt. nitrate of 



soda, 5 cwt. kainit. 

 Plot 3. No super., 1 cwt. nitrate of soda, 



5 cwt. kainit. 

 Plot 4. 5 cwt. super., no nitrate of soda, 



5 cwt. kainit. 

 Plot 5. 5 cwt. super., 1 cwt. nitrate of 



soda, no kainit. 



By comparing the results on plots 2 and 3, 

 one will ascertain the effects of superphos- 

 phate ; by comparing plots 2 and 4 the effects 

 of nitrate of soda will be seen ; and, similarly, 

 by comparing the results on plots 2 and 5 one 

 will learn the effects of kainit. Where the 

 turnip crop is concerned, one may almost 

 assume that phosphate will be required, 

 so that plot 3 might be omitted. It might 

 also similarly be assumed, that a certain 

 amount of nitrogen will be wanted, in which 

 case plot 4 would be dropped from the scheme. 

 But as it can never be assumed that some 

 form of potash will or will not be required 

 it will be necessary to retain plot 5. Simi- 



