April, 191 5 



THE CANADIAN HORTICULTURIST 



91 



Sources of Potash for Agricultural Purposes 



Prof. R. Harcourt, O. 



THE chief source of potassium salts 

 of commerce for both agricultural 

 and industrial purposes in Canada, 

 ind indeed in all parts of the world, has 

 cen the Stassfurt mines in Germany. 

 Unfortunately, one of the evil effects of 

 the disastrous war now raging in Europe 

 is the cutting off of this supply. The 

 potassium salts we have been importing 

 were mainly the muriate and sulphate of 

 potash. Both of these compounds con- 

 (.lin approximately fifty per cent, of pot- 

 ish in a very soluble form. Being both 

 ich in potash and soluble, they were an 

 xcellent fertilizer material either ap- 

 plied directly or for mixing with the non- 

 potash bearing animal refuse of our meat 

 lacking houses in the preparation of the 

 . arious grades of mixed fertilizers on the 

 market. 



Before dealing with our natural 

 sources of potash, it may be well to point 

 out that most of our soils contain very 

 large quantities of this important plant- 

 food constituent. During the last two 

 years we have analyzed a large number 

 of samples of sandy and clayey soils, and 

 we find that they contain from one to 

 two per cent, of potash. Even some 

 sands, as for instance, those of Norfolk 

 county, carry nearly two per cent, of 

 total potash. Or to put it another way, 

 there is about forty thousand pounds of 

 potash in plough depth over one acre 

 and plenty more below that. One per 

 cent, would be equivalent to about 

 twenty thousand pounds in one acre 

 plough depth. When we remember that 

 good crops of cereals do not take up 

 more than fifty pounds of potash per 

 acre and that mangels, our heaviest pot- 

 ash consuming crop, do not use more 



A.C., Guelph, Ont. 



than three hundred pounds of this con- 

 stituent and that the greater parts of this 

 is in the tops which are usually left on 

 the ground, we see that we have potash 

 enough in the soil to last for a long 

 time. Nature has left this im an insol- 

 uble form so that it cannot be wasted ; 

 but she has also provided the means of 

 bringing it into an available form. 



The three main factors to be taken 

 into consideration are good cultivation, 

 abundance of decaying organic matter, 

 and lime. The cultivation assists the 

 decay of the organic matter which fur- 

 nishes certain acid materials which break 

 up the potash compounds of the soil and 

 brings the potash into an available form. 

 The lime neutralizes any excess of acid 

 and also acts as a liberator of potash. It 

 is well to bear in mind that most of our 

 soils contain an abundance of potash and 

 that the farmer's first object should be to 

 bring as much as possible of it into an 

 available form. 



For our light potash consuming crops, 

 such as wheat, oats, and barley , there 

 should be no need of applying potash ; 

 but for such crops as mangels and pota- 

 toes, which use comparatively large 

 amounts of this constituent, we may not 

 be able to bring enough potash and other 

 plant-food constituents into an available 

 form to ensure a maximum crop, here is 

 where manure is needed, or as we are 

 dealing with potash, where it may be 

 applied. What has been said about 

 mangels may also be said regarding all 

 big fleshy-leaved plants, as they all re- 

 quire large quantities of potash. The 

 point we want to particularly remember 

 is that our chief source of potash is in 

 the soil itself and that we ought to strive 



to make full use of what can be got from 

 this source before purchasing supplies. 

 There are, of course, some soils par- 

 ticularly poor in this constituent, and to 

 ivhich, especially if used for market gar- 

 den purposes, potash will have to be 

 applied. 



OTHEE SOURCES OF POTASH 



All vegetable matter contains potash 

 gathered from the soil, and consequently 

 whether we burn it and save the ashes, 

 plough it down, or feed it to animals, 

 we still have potash. The animal retains 

 very little of the potash in the food eaten 

 so that it nearly all appears in the man- 

 ure . Farmyard manure is thus an im- 

 portant source of potash. A large per- 

 centage of it is in the urine, however, 

 and a part of it may be lost unless plenty 

 of absorbents are used. 



WOOD ASHES 



Wood ashes naturally contain potash, 

 as they are derived from plants which 

 absorbed it as an essential plant-food 

 constituent. Good pure unleached ashes 

 should contain about five or six per cent, 

 of potash. It is present in a very sol- 

 uble form and probably in the very best 

 form to serve immediately as plant-food. 

 In this respect it is better than the Ger- 

 man potash salts. In addition to potash, 

 ashes contain one and one-half to two 

 per cent, of phosphoric acid and from 

 twenty to thirty per cent, of lime which 

 still further increase their value. At any 

 time, but especially under present condi- 

 tions, every effort ought to be made to 

 save all wood ashes. This is not only 

 regarding the ashes made where wood 

 is burned as a fuel, but the brush ob- 

 tained from the trimming of trees should 

 be burned where the ashes may be re- 

 covered or on land under cultivation. 



Wood ashes are especially valuable for 

 orchards, grapes and legumes on sandy 



Thoroueh cultivation is one of the secrets of success In strawberry culture. This crop is increasiner in popularity, more particularly In Southern Ontario 



