NURSERY PRACTICE FOR PRAIRIE-PLAINS PLANTING 27 



correct period of time, it is rinsed thoroughly with water. By this 

 method there is no recovery of acid, but it is preferred by many 

 nurserymen because there is less danger of heating and subsequent 

 injury to the seed. 



Obviously, extreme precaution should be taken in using the acid. 

 Goggles to protect the eyes, as well as rubber aprons and gloves, 

 should be worn. Solutions of ammonia, bicarbonate of soda, or some 

 other alkali should be available at all times to neutralize acid which 

 may be splashed on clothes or skin, or the acid may be washed off the 

 skin in running water. Petrolatum (vaseline) should be applied to any 

 burns after the acid has been washed off. Acid should be poured 

 into the container of seed, rather than seed into acid, to minimize 

 splashing. 



After the acid treatment, which should include a careful washing in 

 running water, the seed may be sown immediately. Excellent results 

 have been obtained however, from first soaking the acid-treated seed 

 in cold water until swelling takes place — usually for a few hours or 

 overnight. Where soil-moisture conditions are favorable at the time 

 of sowing, this method should assure prompt and even germination, 

 since the swollen seed is already in the process of germinating. Mixing 

 the wet seed with dry sand or sawdust to absorb the surface moisture 

 will aid in handling the seed during sowing. 



If sowing is not immediately practicable after treatment, the seed 

 can be stored. Briggs 7 has found that the seed of honeylocust, 

 sumac, and soapberry, washed and dried following the acid treatment, 

 may be stored for as long as 5 months with little or no loss in viability. 

 Nurserymen can, therefore, treat the seed of such species during the 

 slack winter months and have it in readiness for spring sowing. Ken- 

 tucky coffeetree seed, however, submitted to the same tests, showed a 

 decrease in germination from 90 percent at time of treatment to 61 

 percent at the end of a 5-month period, and black locust and Russian- 

 olive decreased as markedly. Such reductions appear to be due to 

 the wetting and drying which follow the acid treatment when the 

 seed is not used at once. More research is need-ed on the effect of 

 storage on acid-treated seed. 



MECHANICAL SCARIFICATION 



Another method of rendering the seed coat permeable to water is by 

 mechanical scarification, or the abrasion of the seed coat to crack it 

 or reduce its thickness sufficiently to allow penetration of moisture. 

 This is usually accomplished by placing the seed in a steel drum lined 

 with sandpaper, revolving at about 20 r. p. m. This method has been 

 successfully used by the Forest Service at the Bessey Nursery, Halsey, 

 Nebr., in treating seed of redcedar. 



Other methods have been satisfactory with some types of seed. 

 Hurst, Humphries, and McKee (17) describe several scarifiers used suc- 

 cessfully on sweetclover, among them a disk scarifier consisting of a 

 horizontal stone revolving against an upper stationary disk faced with 

 rubber, the seed being passed between the two disks. Chapman (9) 

 describes a modified Ames seed scarifier in which seed of black locust 

 was treated by blowing the seed with a fan against a curved, sand- 

 paper-lined race. 



7 [Briggs, A. H.] storage of seep after acid treatment. U. S. Forest Serv. Lake States Forest Expt. 

 Sta., Forest Res. Digest, Jan.-Feb., 1936, pp. 10-12. [Multigraphed.] 



