SOIL DISINFFXTION "^''^ 



Soil disinfection in the field has as yet in the main proved 

 impracticable. All promising chemicals have been tried 

 without avail. Electricity has not given beneficial results, 

 and at present there is no hope of any practicable manner of 

 ridding fields of parasites by any process of disinfection. In 

 a few instances large applications of lime, formalin, or sulfur 

 have proved beneficial (see sweet potato, onion, etc.), but 

 the general practicability of such usage is doubtful. 



Disinfection of limited areas is, however, practicable, is 

 largely employed, and has already resulted in great benefit, 

 eliminating not only injurious fungi but insects and weeds as 

 well. Cutting benches, flats, and other benches in the green- 

 house, cold frames, and seed beds, and other small areas 

 may be disinfected with advantage. The means to be em- 

 ployed depend upon the area, its location, and the facilities at 

 hand. The leading methods are given below: 



Baking. — Flats, pots, and other small containers of 

 earth may often be satisfactorily disinfected by placing 

 them upon a boiler or over a stove, or in an oven for a com- 

 paratively long period. 



Permanent steam disinfectors. — A system of 13^-inch 

 pipes, which are p<Mforat(Hl with j 4-inch holes on their under 

 side at intervals of 6 inches throughout their entire length, 

 may be placed about one foot below the surface of the soil. 

 The pipes should run lengthwise of the bed, 18 inches apart, 

 and be connected with a steam boiler. Before treatment the 

 soil should be thoroughly spaded up and pulverized to permit 

 ready access of the steam to all parts, and all fertilizers except 

 commercial ones should be applied at this time, since fresh 

 spores of the fungus are likely to be carried in if manure be 

 added after disinfection. 



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