INJURY BY DISINFECTANTS TO SEEDS AND ROOTS. 



23 



days later resulted in preventing most weed growth., but not all. 

 Ammonia alone, 0.5 ounce per square foot, had no effect on the weed 

 stand 65 days after application. 



TESTS OF MISCELLANEOUS DISINFECTANTS. 



Tests were also made with disinfectants other than sulphuric 

 acid. These are summarized in Table VI, together with enough 

 sulphuric-acid tests to afford a basis for comparison. Because a plat 

 can be directly compared only with the others sown at the same time, 

 the plats are grouped by series rather than by disinfectants. 



Table VI. — Injury to pines and weeds by miscellaneous disinfectants. 



Plat. 



Disinfectant. 



Substance 

 used. 



Per square 

 foot. 



Ounces 



Solu- 

 tion. 



Days from 



treatment 



to- 



Sow- 

 ing. 



Weed 

 exami- 

 nation. 



Injury to pines. 



Weeds present in 

 plats. 



Pinus divaricata: 1 

 60... 



62 



64 



P. ponderosa: 1 

 4152 



4162 



P. divaricata: 1 

 Series 501 (8 

 checks). 



P. ponderosa: •> 

 Series 504 (5 

 checks). 



Copper carbo- 

 nate (basic). 

 Ammonia 



Sulphuric acid 

 do 



do. 



None. . 



0.017 

 .275 



.172 

 .257 



.25 



.125 

 .125 



Pints, 

 1.4 



1.4 

 1.4 



H y drochloric 

 acid. 



Nitric acid 



Sulphuric acid 



do 



do 



do. 



None. . 



Formalin s . . . . 

 Sulphuric acid 

 do 



.375 



.125 

 .141 



2 



1.5 



2 



Germination re- 

 duced to less 

 than one-sixth 

 of that in checks. 

 Nearly all seed- 

 lings which 

 came up were 

 severely injured. 



Injury not serious. 



....do 



Germination re- 

 duced to less 

 than one -quar- 

 ter that on other 

 plats. No death 

 due to disinfect- 

 ant after germi- 

 nation. 



None. 



30-31.. 



30-31. 



30-31. 

 30-31. 

 30-31. 



None. 



Slight or none. 



Slight 



Moderate to heavy 

 Moderate 



Very heavy. 



None. 



.do. 

 .do. 



Portulaca and 

 grass abundant; 3 

 A maranthus re- 

 troflexus common. 



One - half or two- 

 thirds as many as 

 in checks. 



Grass rare; Portu- 

 laca, 2 or 3 plants. 



None. 

 Do. 



A single trifoliate 

 legume. 



None. . 



Mollugo, grass, and 

 Portulacaabund- 

 ant; Amaran- 

 thus and Euphor- 

 bia frequent. 



Half as many as in 

 checks, mainly 

 grass. 



Grass,!at edge only; 

 Equisetum, 2 

 plants. 



Grass, 2 plants. 



1 Watering as in ordinary nursery practice. 



2 Germination exceptionally rapid. 



3 "Abundant" indicates usually 100 or more plants per plat; "frequent" indicates 20 or more ;"common" 

 indicates intermediate numbers. All plats measured 2 by 4 feet. 



4 Watering very frequent. 



5 Plats covered tightly for 3 days after treatment to prevent too early evaporation. 



