920 



Journal of Agricultural Research 



Vol. VI, No. 23 



EXRtAA/A T/ON 

 g PER CENT OF GRAW 

 @ PER CENT OF S7GI/ER 



PER CENT OF BACTER/A 



PER CENT OF &4CTER//4, {FALLOWj 



PER CENT OF AWMON/A 



PER CENT OR AMAfON/A, {FALLOWJ 



PER CENT OR N/TR/C N/TROGEN 



PER CENT OF N/TR/C N/TROGEA'j fFXU.OwJ 



of irrigation water. With the exception of the ammonia produced, the 

 bacterial activities are not as high in the soil receiving 10 as in the soil 



receiving only 5 inches of irri- 

 gation water. The average 

 percentage of the crop pro- 

 duced on this is no, while 

 the average of the bacterial 

 activities is 102 per cent. The 

 application of 20 inches of irri- 

 gation water greatly increased 

 the crop produced and also the 

 bacterial activities, the crop 

 produced being 127 per cent 

 compared with the unirrigated, 

 while using the same compari- 

 son for bacterial activities gives 

 10S per cent. The application 

 of 30 inches of irrigation water 

 causes a slight decrease in the 

 corn produced and also in the 

 bacterial activities of the soil, 

 40 inches of irrigation water 

 producing about the same crop 

 as did 30 inches. But it caused 

 a slight falling off in the bac- 

 terial activities of the soil, espe- 

 cially in the nitrifying powers 

 of the soil. Taking the result 

 as a whole, we find that the 

 bacterial activities of the soil 

 and the crop-producing powers 

 of a soil are both influenced by 

 the application of irrigation 

 water and this in the same di- 

 rection and in about the same 

 degree. These results tend to 

 indicate that the bacteriologi- 

 cal analysis of a soil gives a fair insight into its relative crop-producing 

 powers, being especially true with regards to the ammonifying and 

 nitrifying powers of the soil. 



SUMMARY 



A calcareous soil kept in pots with varying amounts of manure and 

 different percentage of moisture gave on bacteriological analyses at the 

 end of four months the following: results. 



/VO MANURE 



5 toa/s 



OR AWWRE 



/S TONS 

 OF MANURE 



Fig. g. — Diagram of the influence of manure on the yield 

 and bacterial activities ot a soil, the unmauured plots 

 being expressed as 100 per cent. 



