1917] Lipman-Gericlcc : Smelter Wastes and Barley Growth 523 



First Crop 

 Table Villa shows clearly that the application of potash 

 alum in the first crop was distinctly stimulating to the barley 

 plant so far as the production of total dr^^ matter is concerned. 

 The degree of stimulation is not unlike that of CuSO^, ZnS04, 

 and FeS04 iii the first crop and, again, seems to be about the 

 same with the lower as with the higher concentrations. When 

 we consider the root yields separately from the straw yields 

 we find, however, that the former were not increased by the 

 potash alum treatment, though they were scarcely depressed 

 with any concentration of the salt. 



I 



Second Crop 



With the concentration of potash alum doubled in the second 

 crop, the marked evidences of its stimulating effect on barley 

 growth are still manifestly present. The entire series of treated 

 pots, when averages of total dry matter produced are taken as 

 the criterion, gives results far superior to those of the control 

 pots, even though there is variation among the latter and among 

 the treated pots in duplicate cultures. So far as the production 

 of the total dry matter of barley is concerned, there appears to 

 be no evidence in the second crop and very little, if any, in the 

 first, of any toxic properties of potash alum. 



We may now consider briefly the separate parts of the total 

 dry matter as affected by the potash alum. The yield of straw 

 is without exception greater in the treated than in the untreated 

 pots of the second crop of the potash alum series. That part 

 of the total dry matter has therefore been very materially in- 

 creased by the potash alum application. The grain yields in the 

 absolute were of very great magnitude and amounted in many 

 cases to as much by weight as the dry matter of the straw. In 

 some cases they even excelled the latter. This is analogous to 

 the condition of the second barley crop in the CuSO^ series, 

 which was the only one of the other series manifesting as 

 high a grain production. Not only, however, were the grain 

 yields large in the absolute, but they indicated clearly the stim- 

 ulating effect of potash alum on their production, since all the 

 treated pots yielded much more grain than the control pots. 



