18 



PROF. WAGNER ON THE POTASH 

 QUESTION. 



"Exceedingly little is known, even to-day, about all ques- 

 tions referring to potash fertilization. This plant is fertilized 

 with kainit, the other with muriate of potash, the third with 

 sulphate of potash, but without knowing which is correct. 

 It is not known how much the several plants can stand of 

 potash salts without being injured; it is not known which are 

 most, which are least, sensible to potash fertilization; it is not 

 known which plants can only with difficulty draw upon the 

 potash supply of the soil, and for that reason require ample 

 potash fertilization ; it is not known what influence potash fer- 

 tilization exercises upon the quality of the grain, how the other 

 ingredients of the potash salts affect the plants in short, by 

 the results of scientific research, exceedingly little is known 

 about potash fertilization. ' The experience of practical farmers 

 has furnished until now the only material. 



' ' For several years past the experiment station at Darmstadt 

 has undertaken to investigate some practically important ques- 

 tions about potash fertilization through exact experiments, and 

 the results obtained enable me to examine several assertions of 

 Schultz-Lupitz and to test them. 



" I begin with the rather strange assertion of Schultz-Lupitz, 

 which has found much opposition, that cereals, particularly rye, 

 should be fertilized with potash, especially under the form 

 of kainit. Is not this altogether irrational? Cereals are 

 certainly no potash plants. While for the production of an 

 average crop of lucerne, potatoes, sugar beets, etc., about 150 

 kg. (kali) potash per hectar are necessary the cereals are 

 content with about 50 kg. is it possible, therefore, that, as 

 Schultz-Lupitz has found out practically, a kainit applica- 

 tion of 1,200 kg. per ha. for rye is not altogether irrational? 



" It appears to be so, but still, on the strength of my experi- 

 ments, I must answer the question with an affirmative, decided 

 ' Yes. ' First of all, I wish to call attention to the fact that a 

 plant which contains six times as much potash (kali) in its dry 

 harvest substance as another, does not require for that reason 

 a proportionately larger amount of potash (kali) fertilization." 



