268 Bacteria in Relation to Country Life 



from 2° to 3°, a fact of considerable significance in so far 

 as the bacterial activities in the soil are concerned. 

 The modifications introduced, thereby, affect the num- 

 bers and the species relationships of the soil-organisms. 



Still more important are the changed moisture con- 

 ditions induced by fallowing. It was found by King 

 that fallowed land contained in the upper four feet of 

 soil 203 tons of water per acre in excess of that present 

 in similar cropped land. Moreover, this effect of fallowing 

 was felt in the second season. Similarly, in the investi- 

 gations of Hiltner and Stormer in Germany it was 

 found that an uncropped and uncultivated field con- 

 tained at the end of a very dry summer only 2.77 per 

 cent of moisture, whereas, the adjoining field worked 

 as a bare fallow contained 9.28 per cent of moisture. 

 In the first instance, the proportion of water was in- 

 sufficient for the growth of bacteria; in the second in- 

 stance, it was quite ample for this purpose. In the first 

 instance, also, there was but little decomposition in 

 the hiimus; in the second, the roots and the stubble were 

 entirely destroyed. This is in accord with the observation 

 of Wollny, who noted a more intense oxidation of the 

 organic matter in fallowed soil as compared with a 

 similar cropped soil. 



Moisture and fallows. — The larger proportion of 

 moisture in fallowed soil is due largely to the dimin- 

 ished evaporation effected by the stirring of the ground 

 from time to time. In the uncropped, but undisturbed 

 soil, on the other hand, the capillary action is not inter- 

 fered with. Large amounts of water are brought from 

 the deeper layers to the surface, where it is changed into 



