10 June. 1919. J Potash Manures. 369 



potash, 21 X 0.265 = 5.55 per lOQ kg. (= 44s. 5d. per French 

 ton). 

 Potassium Chloride, @ 50 to 60 per cent, of potash (K.O), 375 

 millimes per unit. Say, for a chloride containing 55 of potash, 

 55 X 0.375 = 20.65 fr. per 100 kg. = £8 5s. 3d. per French^ 

 ton. 

 Details follows as to orders, delivery, &c. 



Happily, France is now no longer dependent on German (Stass- 

 furth) potash. She has practically inexhaustible supplies within her 

 new borders. Let us hope that Alsatian potash will ere long be avail- 

 able in the Commonwealth. The low prices mentioned above cannot 

 fail to appeal strongly to vine-growers and orchardists who recognise 

 the high value of this fertilizer. 



POTASH MANURES-SULPHATE OR MURIATE? 



By F. de Castella, Government Viticulturist. 



The superiority of sulphate of potash over the chloride, or, as it is 

 still often termed, muriate, is generally admitted; a contention which 

 received forcible support from a recent article by Professor Degrully,* 

 of Montpellier (France), criticising the form in which Alsatian potash is 

 being made available for French agriculturists (see preceding note). 

 He points out the inferiority of kainit and chloride of potash, as com- 

 pared with nitrate, carbonate, or sulphate, stating that it is under either 

 of the last three forms that potash gives the best results in the majority 

 of soils. 



He quotes an article by M. Lagatu, which appeared in Progres 

 Agricole in 1901, in which attention was very forcibly drawn to the 

 inferiority of the chloride. Professor Lagatu, indeed, goes so far as to 

 assert that in certain cases potash chloride, as well as kainit (in which 

 potash sulphate is mixed with a large proportion of various chlorides) 

 can even be positively injurious. It is largely a question of rainfall. 



" In free limey soil, potash chloride, which is as good as the other potassic 

 manures in the case of medium or heavy rainfall, is harmful if little or no rain 



should fall Chlorides react on the lime contained in the soil, forming 



calcium chloride, a salt injurious to plant life, and especially so to nitrifying 

 bacteria. Being solul)le, heavy rain removes this salt from friable, well drained 

 land .... but if the rainfall be deficient it remains in the soil to the 

 detriment of the plant." ' 



In the case of stiffer limey soil, he is even more emphatic. " Chloride 

 by hindering nitrification, which is usually unsatisfactory in a stiff 

 soil, should be altogether avoided. In all stiff soils it is not a manure, but 

 a poison. Potash sulphate presents no danger. It even favours nitrification." 

 He further points ovit that in very free soils, where, owing to its great solubility, 

 the calcium chloride is readily removed by the easy circulation of rainwater, no 

 injurious chloride remains; but should drought supervene, it will again cause 

 damage. 



Professor Degrully also quotes from a letter by M. Octave Audebert, 

 President of the Agricultural Society of Gironde, to the French Minister 

 of Agriculture, protesting against the potash salts recently made 



» Pro!7r(<s ^?WcoZ«, 19th .Tan., 1919. 



