69 



PLATE XT. 



Experiments made by Mr. Wermter, of East Prussia. 

 Photograph of produce from 4 perches. 



Stnbledung and 



8 cwt. Thomas phosphate 



3 cwt. nitrate of soda 



Stabledung, 

 156 cwts. per acre. 



of 40/ kainit 

 (or 214 Ibs. rauriata of potash) 

 250 cwt. per acre. 



Professor Dr. Wagner gives his latest experiences with nitrate' 

 of soda and sulphate of ammonia. He referred to half an acre cf 

 potatoes manured with I*, cwt. of nitrate of soda, arid another half 

 an acre which received sulphate of ammonia, containing an equal 

 quantity of nitrogen. Of both he used one-half on the 18th April 

 with the planting of the tubers, and the other half on the 2nd of 

 May as a top-dressing. The half an acre with nitrate of soda had 

 33 cwt. more potatoes than an unmanured half an acre ; but sul- 

 phate of ammonia gave 45 cwt. .He 1 explains this that the soil 

 was very percolative, and the spring of 1898 had so much rain that 

 the nitrate was more washed out than the sulphate of ammonia. 



Dr. G. Smets says in "La Potasse" of 1900 that potash applied 

 in too great a quantity can interfere with the first development 

 cf the potato plant and the starch, but if applied earlier, potash 

 can considerably increase the crop, even double it. In the sands 

 of the Campine he obtained 30' per cent, more through potash, 

 which should be applied to a former crop, or in winter. Entire 

 tubers are four times as safe to use with potash than cut tubers. 

 



