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



921 



The temperature of the manured and unmanured averaged practi- 

 cally the same for the period, but the temperature of the soil with 12.5 

 per cent of water averaged 1 degree centigrade higher than did soils with 

 22.5 per cent of water. The greatest number of organisms developed on 

 synthetic media from the soils receiving the greatest quantity, 25 tons, of 

 manure. There were more colonies developed from the soil receiving 

 12.5 per cent of water than from any of the other soils receiving higher 

 quantities of water. 



/3Z 



SB& 



/OO -m-g 



0* 



ee- -1 



A/O kVstrr/P 



£ /AJCHE& & JO/A/C/t>£S SO /A/C^SS 



30 /A/CW£& <40 /MC-.HFS 



Fig. 10. — Diagram of the influence of irrigation water on the yield and bacterial activities of a soil, the 

 nonirrigated plots being expressed as 100 per cent. 



The ammonifying powers of the soil increased with the manure 

 applied up to 25 tons of manure per acre, but the greatest increase per 

 ton of manure was obtained in soil receiving 5 tons. 



The ammonifying powers of the soils increased as the water applied 

 increased until 20 per cent of water was applied. The ammonifying 

 powers of soil receiving 22.5 per cent of water were not as high as were 

 those of soil receiving 20 per cent of water. The greatest increase per 

 unit of water applied was when the water was increased from 12.5 to 15 

 per cent of water. 



