sept. 4 , 1916 Influence of Barnyard Manure on Soil Bacteria 



911 



it is not as pronounced as it is in the fallow soil. The same general 

 order is seen during spring and fall, but in the fall the difference is 

 greater in degree and more regular than in the earlier part of the year. 

 The application of irrigation water produces an increase with the lower 

 applications, especially on the heavily manured soil. The irregularity 

 of this set as compared to the fallow can be accounted for in a degree 

 by the error entering in sampling, for in some cases the sample may be 

 taken nearer a plant than in others and in the cultivation and irrigation 

 the tendency would be to leave the soil less homogeneous in the cropped 

 than in the fallow plots. These conditions were borne in mind at the 

 time of sampling and efforts made to get representative samples, but 

 the results show that much more care must be taken on cropped than 

 on fallow soil. The results for this series of plots are given graphically 

 in figure 6. 



Table VII. — Number of colonies of bacteria developing in four days on synthetic agar — 



cropped plots 



