No. 4.] MANURIAL PROBLEMS 149 



<s. It appears that no one is justitiod in drawing general 

 conclusions as to tiic value or the worthlessness of sodium from 

 experiments with only a single kind of plant, or even with 

 a few kinds ; but that practically each kind of i)lant must 

 b(> experimented with before a j)roper basis for conclusions 

 regarding it is reached. This would signif}^ that the sodium 

 lu'oblem, so far as concerns plant growth, is neither an easy 

 nor a quick one to solve. 



9. It is (|uite possible that, in endeavoring to limit the 

 su})ply of potassium enough to enable sodium to become 

 eftective as a direct manure, there will be danger of depress- 

 ing it enough in some instances to materially lessen the 

 crop, in which case the attempted gain in cheapening the 

 manures would be offset by a direct loss of crop. 



10, The most practical side of the sodium question, and 

 one to which, so far as I am aware, no one has heretofore 

 called attention directly in an economic way, is the fact of 

 its conserving the potassium supply of the soil, when those 

 l^lants are grown which readil}^ take uj) considerable amounts 

 of sodium ; for, if some sodium is not present and the soil 

 contains more than enough potassium to actually produce 

 the crop, in lieu of taking so much sodium they will remove 

 from the soil more potassium than they re(|uire. 



Even this benefit could not be expected to an appreciable 

 extent in cases like those of millet and oats, Avhich refuse 

 under any circumstances to take up more than minute quan- 

 tities of sodium. By way of practical illustration, let us 

 suppose that a farmer is intending to grow a crop of turnips 

 or beets, or some other crop which assiriiilates sodium 

 readily, upon land which is in good condition, and upon 

 which it is reasonable to suppose that there is present an 

 amount of potassium possibly somewhat in excess of the 

 requirements of the crop. It is obvious that, if nitrogen is 

 ai)plied in the manures in nitrate of soda, a certain quantity 

 of sodium will be at hand to satisfy some of the demand for 

 unnecessary amounts of potassium which might otherwise 

 be made by the plant. If, on the other hand, the nitrogen 

 is supplied in sulfate of ammonia or in organic materials, 

 such a conservation of the natural supply of potassium would 



