ANTISEPTIC TREATMENT OF SOILS. 169 



The EFFECT of HEATING and ANTISEPTIC TREAT- 



MENT on the SOLUBILITY OF FERTILISING 



INGREDIENTS in SOILS. 



By H. I. Jensen, d.sc, 



Chemist's Branch, The Department of Agriculture of 



New South Wales. 



[Read before the Royal Society of N. S. Wales, August 2, 1911 .] 



In the end of 1909 Russell and Hutchison 1 announced the 

 interesting discovery that when a soil is heated to 95° C. 

 it produced two, three or four times as much crop as a 

 portion of the same soil which had not been so heated. They 

 also found that the treatment of a soil with volatile anti- 

 sceptics (toluene, carbon bisulphide and other substances) 

 led to an increase in crop varying from 20°/° to 50°/°. They 

 concluded that treatment of the soil by these means led to 

 an accumulation of ammonia in the soil and an increase of 

 unstable nitrogen compounds. This increase was not at 

 the expense of the humus, but a slight increase in humic 

 nitrogen was also noted. The change in total nitrogen 

 after partial sterilisation is not great, there being an 

 increased amount of ammonia and a diminished amount of 

 nitric nitrogen present. 



Partial sterilisation therefore seems to increase the 

 activity of ammonia-producing bacteria, and Russell and 

 Hutchison explain the increased bacterial activity as being 

 due to the destruction by partial sterilisation of amoebae 

 and like organisms which feed on bacteria. 



Pickering 2 showed in December 1908 that soil heated or 

 treated with antiseptics contains more water soluble salts 



1 The Journal of Agricultural Science, Vol. in, part 2, Oct. 1909. 



2 Ibid., Vol. in, part 1, Dec. 1908, also ibid., Vol. in, part 3, Sept. 1910. 



