150 BOARD OF AGRICULTURE. [Pub. Doc. 



not result. For this reason the use of nitrogen in nitrate 

 of soda may be an especially important economical feature 

 in connection with some kinds of plants, entirely aside from 

 any advantage accruing on uccoutit of a greater jiossible 

 assimilability of the nitrogen (?) or of the advantage of a 

 basic residue being left in the soil to counteract the natural 

 tendency to acidity. 



Even though Jordan and Jenter and also various European 

 investigators have apparently dismissed the sodium question 

 as settled, it would seem as if we were but entering the por- 

 tals of possible discovery regarding its actual place as a 

 direct and indirect manure. The problem of the influence 

 of excessive sodium assimilation as compared with a rela- 

 tively greater assimilation of potassium upon the quality and 

 feeding value of plants is a particularly inviting phase of the 

 problem 3'et to be studied. This seems particularly the case 

 when we bear in mind that sodium is much more essential in 

 the animal economy than potassium, and that it is possible 

 that crops containing more sodium and less potassium may 

 possess certain advantages for feeding purposes. It is pro- 

 posed, if time and means allow, to enter eventually upon a 

 study of this side of the problem at the Rhode Island station. 



Concerning Certain Piiosphatic Manures. 



In view of having discussed the <|uestion of phosphatic 

 manures in detail in the former paper, no attempt will be 

 made here to enter into a detailed description of all of the 

 diflerent materials which furnish phos})horus to the plant. 

 On the contrary, it is intended to merely hint briefly con- 

 cerning the relative value of the more conmion of the phos- 

 phatic manures, and to pay especial attention to two sources 

 of phosphoric acid concerning which new and striking data 

 have recently been obtained. 



It is still fully accepted that ' ' soluble " phosphoric acid is 

 equally valuable, whether in dissolved bone-black, dissolved 

 bone or in acidulated rock phosphate, which latter product 

 is known in the market as plain superphos})hate, dissolved 

 phosphate rock and acid phosphate. 



Before dismissing this matter, it should be stated that. 



