2l8 



Journal of Agricultural Research 



Vol. Xin, No. 4 



A consideration of Table II shows there is no apparent stimulation or 

 depression of ammonification in sandy loam until a concentration of 

 0.200 per cent of calcium nitrate is reached, when a marked depression 

 occurs, and is followed by further slight depressions with each succeeding 

 addition of the salt. The freezing-point determinations show a well- 

 defined increase in the osmotic pressure of the soil solution when 0.032 

 per cent of the salt is added, with a further increase with each succeeding 

 increase in the amount of calcium nitrate added. 



With clay loam there is apparently no stimulation of the bacterial 

 activities such as occurred in the case of magnesium sulphate. The two 

 series are similar, however, in that there is no point at which the salt 

 exhibits a marked toxicity such as is seen in the case of sandy loam. 



The osmotic pressure of the soil solution is decidedly increased when 

 0.064 P^r cent of calcium nitrate is present, and steadily rises as more 

 of the salt is added. 



Table III. — Ammonificatian of dried blood in sandy loam and clay loam with varying 

 percentages of calcium chlorid 



Salt in air-dry soil. 



Sandy loam. 



Clay loam. 



Nitrogen 

 produced. 



Depression 



of freezing 



point. 



Osmotic 

 pressure. 



Nitrogen 

 produced. 



Depression 



of freezing 



point. 



Osmotic 

 pressure. 



Per cent. 



o. 000 



. 001 



. 002 



. 008 



. 016 



• 032 



. 064 



. 100 



. 200 



.300 



. 400 



■500 



. 600 



. 700 



Mgm. 



'C. 



0. 285 

 . 280 

 . 290 

 .280 

 .316 

 •353 

 • 450 

 •523 

 .708 



1.068 



1-385 



1. 620 



A itnos- 

 pheres. 



435 

 375 

 496 



375 

 809 



255 



423 



302 



528 



856 



660 



48 



660 



Mgm. 

 52. 10 

 46. 13 



43- 19 



42. 21 

 50.90 



55- 10 

 49. 22 



47- 12 



44-31 

 45- 29 



'C. 



o. 276 

 .280 



.300 



315 

 320 



430 

 470 



810 



I. 163 



1-455 



A imns- 

 pheres. 



3-327 



3-375 



3.616 

 3-797 

 3-857 

 5.182 

 5.664 



9-755 



13. 996 



17. 500 



When calcium chlorid is added to sandy loam, we again see (Table III) 

 an apparent slight stimulation of ammonification with o.ooi, 0.002, and 

 0.008 per cent of the salt; but when 0.016 per cent is added, the process 

 is reduced to normal; and with 0.064 per cent there occurs a marked 

 depression. With further addition of the salt, ammonification is 

 depressed as a whole, but the results are irregular. 



The freezing points of the soil show that an increase of osmotic pres- 

 sure occurred when 0.016 per cent of calcium chlorid was added, which 

 agrees with the point brought out in Table II — namely, that an increase 

 in osmotic pressure of the soil solution is observed with amounts of salts 



