Treatment of Sick Soils 45 



Table 3 



Date 



No. of Blossoms Picked 



Percentage 



Unsterilized 



Sterilized 



uatn 





Soil 



Soil 







19 



38 



100 





62 



lOI 



63 





55 



125 



127 





39 



72 



84 





144 



250 



73 





482 



510 



5 



Total 



801 



1,096 







133 



182 



'36 



Not only was production of flowers increased in 

 the sterilized soil, but there was also a decided de- 

 crease in leaf spots. 



Changes in the Soil due to Sterilization, Vari- 

 ous investigators have found that by steam heat- 

 ing, the physical, chemical, and physiological prop- 

 erties of a soil are more or less changed. Through 

 chemical action there is an increase of soluble mat- 

 ter in some of the inorganic substances such as pot- 

 ash and phosphoric acid as well as in the organic 

 matter. Ammonia is also formed by the reduction 

 of nitrates to nitrites and by the decomposition of 

 organic compounds, large amounts of which are also 

 made available for plant growth. This, then, would 

 explain the reason of the stimulation of growth in 

 sterilized soils. However, steamed soils may also 

 contain injurious substances, which upon becoming 

 soluble are harmful to plant growth and to the ger- 

 mination of certain seed. This seems especially the 



