FIELD CROPS. 



141 



In the following table are the average results obtained from several 

 pots in the pot experiments and from two plats in the plat experiments : 



Yield of tubers and starch in 1895 and 1896 and a comparison of their production with 



and without potash. 



Kind of pot- 

 ash fertilizer. 



No potash 



Pure potassi- 

 um chlorid . 



Pure potassi- 

 um sulphate 



Pure potassi- 

 um sulphate 

 and magne- 

 sium chlo 

 rid (34.05 

 per cent 

 chlorin) 



Kainit (33.45 

 per cent 

 chlorin) . .. 



Hartsalz (38.45 

 per cent 

 chlorin) . . . 



Pot- 

 ash 

 ap- 

 plied 

 per 

 pot. 



Yield per pot and per plat, 

 1895. 



Pot experi- Plat experi- 

 ments, ments. 



Gm. 

 301.3 

 331.7 

 322.2 

 330.0 

 341.2 



325.0 

 255. 2 



317.6 

 292.0 



226.5 

 278.2 



Gm. Gm 



40.55 3,970.5 



g-jElk088.7 



50.18 

 39.30 



(?)33.93 

 40.17 



4, 058. 5 



Gm 

 674.7 



767.3 

 773.2 



641.6 

 633.5 



Increase (+) and decrease (— ) of 

 tubers and starch, calculated 

 per acre, compared with yields 

 obtained without potash, 1895. 



Pot experiments. **£%*■ 



Lbs. 



+ 3,358 

 + 2,316 

 + 3, 171 

 + 4.409 



+ 2,619 

 —5, 095 



/ +1,800 

 \ -1,024 



/(— 8,266?) 

 \ —2, 547 



Lbs. 



+1, 283 

 + 793 

 4- 962 

 + 900 



615 



588 



+ 1,069 

 - 134 



(—730?) 

 — 45 



Lbs. 





-7, 891 



1+ 



Lbs. 



+ 819 



+ 873 



—1,683 



Yield from 

 plats, 1896. 



Gm. Gm. 



1,660.3 324.8 



1, 611. 302. 2 



1,705.8 323.5 



1,654.2 285.7 



1,739.0 333.1 

 1,533.5^ 290.1 



The amount of potash, lime, magnesia, chlorin, and sulphuric acid in 

 the tubers and in the stems and leaves, and the amount of starch in 

 the tubers is given in tables. 



The following table gives the average mineral constituents of the 

 fresh tubers for both seasons : 



Average mineral constituents of fresh potatoes. 



1895. 

 1896. 



Potassi- 

 um oxid. 



Per cent. 



0.506 



.524 



Calcium 

 oxid. 



Per cent. 



0.016 



.013 



um oxid. 



Per cent. 



0.039 



.038 



Chlorin. 



Per cent. 



0.067 



.022 



Sulphuric 

 acid. 



Per cent. 

 0.095 

 .084 



It is suggested that the low yields in 189G and the small chlorin 

 content for the same year, which showed itself in the stems and leaves, 

 may possibly be connected, but that from a single experiment no such 

 conclusion could be safely drawn. From the results obtained the 

 authors draw the following conclusions: 



Potassium chlorid applied immediately before planting potatoes in 

 quantities furnishing up to 250 kg. of potash per hectare (about 220 

 lbs. per acre) is as beneficial as an application of the sulphate supply- 

 ing the same amount of potash. Under these conditions the chlorin 

 contained in the chlorid is not detrimental to the growth of the plants. 



