July 15, 1920 



Presoak Method of Seed Treatment 



375 



EFFECT OF PRESOAKING WHEN USED WITH COPPER SULPHATE FOR WHEAT AND 



BARLEY SEED 



The striking reduction in formalin injury to seed germination when 

 the presoak method was used led to trials of this method in conjunction 

 with copper sulphate. Six hundred wheat seeds of Fife and Fulcaster 

 varieties were soaked in a very strong copper-sulphate solution (i :8o, or 

 I pound to 10 gallons of water) for 10 minutes, drained 20 minutes, dipped 

 for a moment in milk of lime, and dried. A like number of seeds received 

 the same treatment except that they were kept moist for 8 hours after 



PERCENTAGE OF GERMINATION 



30 40 50 60 70 80 90 



100 



FULTZ 



^TENNESSEE WINTER 

 ■ZZI (BARLEY) 



Fig. 4. — Graph showing effect of copper sulphate i to 80, with and without presoaking, on wheat and barley 

 seed germination: A, control, untreated; B, seeds soaked in copper sulphate i to 80 for 10 minutes, 

 drained, kept moist 20 minutes, then limed, dried overnight, and planted ;C, seeds first soaked in water 

 10 minutes, drained, and kept moist (covered) for 8 hours, then treated as in B; D, seeds first soaked in 

 water 10 minutes, drained, kept moist (covered) for 6 hours, then limed, dried overnight and planted. 

 Records of germination were taken on the fifth and seventh days after planting in the greenhouse. 



soaking lo minutes in tap water. Four hundred seeds were used as con- 

 trols. All seeds were planted in the greenhouse after drying overnight. 

 The experiment was later repeated, using barley also and wheat seeds 

 of Fultz and Marquis varieties, kept moist in the manner described for 

 6 hours before treatment. The photographs (PI. 76, jy) and figure 4 show 

 the results obtained. 



In these experiments the injury produced by the copper-sulphate 

 treatment was prevented by the use of the 6- or 8-hour presoak. The 

 6-hour presoak appears preferable, because a longer period, by starting 



