SOILS AND FERTILIZERS 453 



Muriate of potash is extensively used as a source of potash in 

 fertilizers. It is a very concentrated fertilizer, each 100 pounds of 

 it containing about 50 pounds of actual potash. The potash in this 

 form is, as a rule, somewhat cheaper than in the form of sulphate 

 of potash. If, therefore, it is as effective as the sulphate and 

 does no injury to soil or crop it is advisable to use it in prefer- 

 ence to sulphate. It has been found, however, that although the 

 muriate of potash is, as a rule, a very valuable fertilizer the chlorin 

 with which the potash is combined in it may injuriously affect the 

 quality of certain crops, such as potatoes, tobacco, etc.; and Pro- 

 fessor Goessmann, of the Massachusetts station, has observed that if 

 the muriate is used without proper precautions on soils with a limited 

 supply of lime that full benefit of the potash which it supplies may 

 not be obtained because the lime of the soil is converted into a solu- 

 ble form which is either washed out in the drainage or accumulates 

 in the upper soil and poisons the plants. He observed that oats, rye, 

 and soja beans grown on soil wnich had received applications of 

 muriate of potash for a number of years in succession continued to 

 decrease in yield and were unhealthy in appearance, and it was sus- 

 pected that this condition was due to the action of the muriate of 

 potash on the lime of the soil. 



When common salt (sodium chlorid) and muriate of potash 

 (potassium chlorid), which are readily soluble, are brought in con- 

 tact under favorable conditions with the insoluble carbonate of lime, 

 the form in which lime chiefly occurs in the soil, a chemical change 

 takes place by which the lime is converted into a form (chlorid) 

 soluble in water and poisonous to plants. An examination of the 

 drainage water of the soil showed the presence of considerable 

 amounts of the soluble lime compound (chlorid) in the soil fer- 

 tilized with muriate of potash (much greater than where sulphate 

 had been applied), and thus confirmed the opinion that some such 

 chemical change as the above had actually taken place in the soil. 

 The valuable potash had passed into more insoluble forms and was 

 thus protected from leaching a very desirable result but this was 

 accomplished at the expense of the lime. If lime is abundant in the 

 soil and drainage good no immediate harm is likely to result from 

 such a change in a favorable season, but if the supply of lime is 

 limited, serious results may follow the continued use of muriate of 

 potash unaccompanied by applications of lime. The conclusion that 

 the unhealthy appearance and decrease in yield of the crops were 

 due to loss of lime from the soil was confirmed by the fact that when 

 500 to 600 pounds per acre of lime was applied broadcast early in 

 the spring, and subsequently plowed under before preparing the soil 

 for manuring and seeding, the succeeding crops of oats looked 

 healthy from the beginning to the end of the season. 



On account of the poisonous properties of the lime compounds 

 formed, muriate of potash is a safer fertilizer on a deep soil with 

 open subsoil than upon a shallow soil with a compact clayish sub- 

 soil, because in the former the injurious lime compounds formed 

 pass readily out of the reach of plants, while in the latter they tend, 



