EXPERIMENT STATION RECORD. 



Vol. XIX. May, 190s. No. 9. 



The proportion of the different mineral or ash constituents in farm 

 crops and other agricidtiiral pro(hicts has been a question connnoniy 

 studied by experiment station observers, such work having been under- 

 taken most often from the standpoint of the draft which the phmt 

 makes on the soiL It Avas argued that the material removed by the 

 plant from the great storehouse of mineral matter in the soil must 

 be returned as fertilizer or the fertility of the soil would diminish. 

 In such studies of ash constituents the function of mineral matter in 

 plant life processes and other questions were not usually considered. 

 However, studies have been by no means rare in wdiich questions of 

 plant physiology have been taken up with a view to securing a better 

 understanding of mineral matter in relation to plant physiolog}^ 



The problem of the use wdiich the animal makes of the mineral 

 matter supplied by the plant has received less attention than almost 

 any other of like importance connected with the subject of animal 

 nutrition, the general assumption being that the animal would secure 

 from the usual food supply enough of the ten or twelve mineral ele- 

 ments regarded as essential. A reason for this belief has been the 

 fact that the total demand for mineral matter is relatively small after 

 the body has attained its growth, and that the ordinary feeding stutfs 

 contain some or all of the mineral constituents regarded as essential ; 

 and hence with a comparatively wide range of feeding stuffs and a 

 reasonably generous ration it might be supposed that the animal 

 Avould secure all that was needed. In the case of common salt, how- 

 ever, an exception may be noted, for it has been a general farm prac- 

 tice to supply salt to farm animals, the custom being a very old one 

 and undoubtedly based on the observed fact that wild animals so gen- 

 eralh' seek salt licks, in response apparently to an instinctive demand 

 for this addition to their food. Sulphur, Avood ashes, or some similar 

 material is not infrequently supplied with salt, but doubtless more 

 often with the idea of providing a tonic or vermifuge than mineral 

 matter required by the animal body. 



That domestic poultry require mineral matter in the form of grit 

 for their digestive processes and lime for the formation of eggshells 

 is, of course so generally believed that it need only be mentioned. 

 The relation of mineral matter to egg yield and to other poultry 

 problems has been a profitable field of experiment station inquiry. 



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