INJURY BY DISINFECTANTS TO SEEDS AND ROOTS. 



21 



Table V. — Injury to roots in plats treated with sulphuric acid 12 to 16 days before sowing 



and later treated with lime. 





Treatment (per 

 square foot). 



Days from 

 acid treat- 

 ment to — 



CD ID 



3 s 



a 1 



~ W 

 <D 

 > *-* 



°ft 



'§! 



S'3-s 



ssl 



a. a 

 a? 



O CD 

 03 fl 



MO 



I® 

 II 



i 



.3 

 ft 



o 



B 

 '3 





Plat. 



o 



CD 



a 

 o o 



03 



a 



'3 



a 



o 



"o 

 o 



.g 



CO*'-' 



o° 

 ft 

 a 



■OO ci 



o3<3 



> oO 



«! 

 ■O 



ft 



a 



2 



_o 



03 



.a 



a 



s 



o 



Weeds present H months after 

 acid application. 



PInus ponder- 

 osa (series 

 504-E) 



P. divaricata 

 (series 507): 



0.375 



None. 



.375 

 .500 

 .500 

 .500 

 .750 

 .750 

 .750 



2 



3 

 2 

 4 

 4 

 4 

 2 

 6 



0.250 



None. 



.250 

 .333 

 .333 



.200 

 .333 

 .500 

 .500 

 .125 

 .250 

 .375 

 .500 



None. 

 .333 

 .250 

 .500 



14 



25 



0.240 



36 



None. 



Half as many as in check plats 

 of same series. 



Grass and Mollugo abundant; 

 some Amaran thus, Portulaca, 

 and Euphorbia in each plat. 



Very few, mainly grass and 

 Mollugo, but growth much 

 more vigorous than in 

 checks. 



M 

 G 

 K 

 P 

 E 

 L 

 

 F 



6 



8 

 9 



7 

 7 

 7 

 7 



20 

 23 

 24 

 22 

 22 

 22 

 22 



.240 

 .321 

 .321 

 .392 

 .571 

 .481 

 .481 



36 

 36 

 36 

 22 

 24 

 36 

 36 



Slight. 



None. 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.. 

 Slight. 



None.. 

 ...do... 



C 



...do... 

 ...do... 















K 











...do... 



plats, in vigorous condition. 



A 



...do... 













...do... 



P. resinosa 

 (series 514): 



None. 

 .500 

 .500 



2 

 4 













Grass, Mollugo, Euphorbia, 

 Portulaca, and Amaranthus. 



Less than in checks; grass, 

 Mollugo, and Euphorbia. 



Less than' in checks; grass, 

 Euphorbia, and Amaranthus. 



J 



K 



N 



5 



5 



24 

 24 



.321 

 .365 



36 



27 



None. 

 ...do.. 

 ...do.. 





















1 Based on equivalent weights, assuming for the commercial sulphuric acid a maximum specific gravity 

 of 1.84 and a purity of 95 per cent. No allowance is made for impurities in the lime. 



It appears that at least in plats M and O the acid applied was not 

 reduced to two-fifths of its original amount during the first six or 

 seven days after application. The injury in plat M, with its acid 

 excess of only 0.24 ounce, when compared with the lack of serious 

 injury in other plats with a greater excess of acid (notably plat E, 

 with an excess 2f times as great), is a further indication of the 

 relative stability of weak acid solutions in the soil. 



In the case of series 514, acid injury occurred in a plat treated with 

 a relatively small amount of hydrochloric acid, and it is quite certain 

 that only the lime prevented injury in plats J and K. 



Ammonia was also tested, following sulphuric acid. On jack pine, 

 0.750 fluid ounce of acid applied 21 days before sowing was followed 

 a few days later by 0.469 ounce of the strongest commercial grade of 

 ammonia. No injury to pines occurred. Watering in this series 

 was very frequent, so injury might have taken place with ordinary 

 watering despite the lime used. In series 514, a red-pine plat 

 treated with 0.562 ounce of acid 13 days before sowing, followed by 



