56 



As shown in Table IX, the addition of ammonium sul- 

 phate to these acid soils caused an increase in the solu- 

 ble manganese in each of the soils, with the exception 

 of number 75. In several of the soils, ammonium sul- 

 phate was nitrified so poorly that it seemed worth while 

 to repeat the experiment; and this was done as far as 

 the supply of soils at hand would permit. The method 

 used was changed somewhat, in that dried blood was 

 used in this instance at the rate of .1 gram for 50 grams 

 of soil. The solution for analysis was obtained by 

 leaching the soil on a filter paper held in a large fun- 

 nel, until 100 cc of Icachings were obtained. In case 

 extracts were turbid, a little calcium nitrate was added 

 to clear the solution. This was done, where necessary, 

 after part of the extract had been analyzed for nitrates, 

 A treated and an untreated portion was used in this 

 experiment, to determine if the unfertilized soil devel- 

 oped soluble manganese. The soils were incubated at 

 laboratory temperature from August 13 to November 

 20, 1917. The results obtained by this method are to be 

 found in Table X. 



Table X. — The Effect of Nitrification of Dried Blood on 



the Development of Soluble Manganese in Acid 



Soils. NO:^ and Mn. in p. p. ni. of Air Dry Soil. 



'Sample No. 1 is Plainficld sand, and sample No. 2 is Mar- 

 .shall silt loam, both of which were kindly furnished by E. 

 Truog of the Wisconsin Agricultural Experiment Station. 



