120 GRASSES OF IOWA. 



result of the experiment. In order to show that there is no 

 question in regard to these results, the accompanying figures 

 show a marked difference between treated and not treated 

 plants, kept under the same conditions. Quite a large num- 

 ber of experiments have been made in testing the effects of 

 chemical solutions on the germination of corn, and it has been 

 shown that quite a large number of salts act injuriously, and 

 even a weak solution sometimes checks the germination of 

 corn. The conclusions reached by several investigators are 

 here given. It was very evident in some work conducted by 

 Pammel and Stewart* with the copper compounds that even 

 the very weak solution retarded and in some cases prevented 

 germination. 



Thus, for instance, when corn was soaked for two hours in 

 ordinary copper sulphate solution, more than three-fourths 

 would not germinate. Ammoniacal carbonate of copper was 

 also used. When the corn was soaked in it for two hours only 

 twenty-seven kernels out of 100 grew, but when the treatment 

 was continued for only one hour fifty-seven kernels grew. 



In an exhaustive paper on the subject by Hitchcockf and 

 Carleton, t they state in regard to ferrous sulphate that corn 

 soaked for twenty-four, forty-eight and seventy-two hours, 

 respectively, gives the following percentages of germination: 



Time of immersion 24 48 72 



Percent 24 20 17 



The germination was from 80 to 100 per cent of that obtained 

 with water, but retarded. Prof. L. R. Jones]: concluded that 

 soaking corn in Bordeaux mixture for one hour and less, had 

 no perceptible effect, and soaking six hours was slightly bene- 

 ficial. Soaking in copper sulphate solutions, of either strength, 

 for lengths of time up to fifteen minutes, did no apparent 

 injury. Soaking one hour was slightly injurious. But, after 

 all, the substances which have been experimented on, among 

 them ferrous sulphate, have been widely used to better the 

 soil. Mayer§ shows that 200 grams of iron sulphate acted inju- 

 riously on rye, barley and oats, and that 100 grams on wheat. 

 This quaatityof iron sulphate was added to sixteen kg. of 

 soil. 



*Agrl. Scl. 8: 215. 

 tBull. Kansas Agrl. Exp. Sta. 41. 



TAnn. Report Vermont Agrl. E.vp. Sta. 1891: 139-141. 



§Nederlandsch Landb. Weekblad. 31: 2. 1892. Bledermann's Centr. Agrlkul- 

 turch. 22: 158. 



