CORN AND STRAW CONSTITUENTS IN SOILS. 201 



certain additional qnantity of the K constituents is con- 

 sumed, wliicli woidd otherwise have served to form seed. 

 Let st represent the additional supply of ^t constituents 

 afforded by the soil under these circumstances, and dk the 

 additional portion of K converted into straw-consti- 

 tuents ; then the alteration in the produce may be 

 expressed as follows : — 



Com Straw 



(K-ak) + (rtK St + ak st) 



that is, the produce of straw increases, while that of grain 

 diminishes. It is also evident, that Avhere the St consti- 

 tuents are in excess and the amount of K constituents is 

 increased, then if K is proportionately deficient there will 

 be an increase in the produce of straw, and if K is pro- 

 portionately increased there will be a larger produce both 

 of corn and straw. 



As the constituents of K, with tlie exception of ni- 

 trogen and phosphoric acid, are also constituents of S^, 

 this accession of produce in the field under consideration 

 will be also effected either by a supply of phosphoric 

 acid, or of nitrogen, or both together. 



If by this supply the closeness of the K particles in 

 the ground, or of the phosphoric acid and ammonia 

 particles, is doubled, then under the most fiivourable 

 circumstances the harvest may be doubled by the su|)ply 

 ofK. 



If, on the other hand, the soil is deficient in S/ consti- 

 tuents, any increase of nitrogen or phosphoric acid in the 

 ground will fail to exercise tlie slightest influence upon 

 the crop. 



It results from this, as a matter of course, tliat the 

 absolute or relative amount of straw, given by a field in 

 a crop of corn, will furnish no proof of the S^ consti- 

 tuents in the soil : since, though two fields may be equally 



