28o 



SOIL CONDITIONS AND PLANT GRO WTH 



another great group of organisms, and which we must now 

 proceed to discuss. 



Investigation on the Partial Sterilisation of the Soil. 



The earliest observations that soil is altered by an ap- 

 parently inert antiseptic arose out of attempts to kill insect 



Le Reveil de la Terre (Miintz and Gaudechon) 

 Rate of Nitrification. 



I60O 



1200 



800 



4.0O 



Feb AprJ... May Feb. Apnl 



'* Terra 9 Terreau 



Bacterial numbers in soil : plots IB and 46. Cropped with millet unmanured. 

 (The curve showing moisture content is very similar to that for 48.) (Conn.) 

 FIG. 27. Bacterial activity in soils at different seasons of the year. 



pests in the soil by means of carbon disulphide. This sub- 

 stance, which for fifty years has been known as an insecticide, 

 was used in 1877 by Oberlin, 1 an Alsatian vine-grower, 



Boden-Mudigkeit und Schwcfelkohlcnstoff, Mainz, 1894. 



