FIXATION OF PLANT FOOD BY SOILS 



563 



TABLE 1 18. NITROGEN AND CHLORIN IN DRAINAGE WATER BEFORE AND AFTER 



THE APPLICATION OF AMMONIUM SALTS ON OCTOBER 25, 1880: 



PLOT 15, BROADBALK FIELD 



Pounds per Million of Water 



found in the early drainage waters, a circumstance which is very unusual. 

 That decomposition of the salt had already taken place to a very large extent, is 

 shown, however, by the enormous amount of chlorin in the first runnings, an 

 amount far exceeding that of the ammonia. 



" Even at this early stage of the reaction, only forty -eight hours after the ap- 

 plication of the ammonia, nitrification has made a distinct commencement." 



While the ammonia fixation was probably completed soon after 

 October 29, the process of nitrification was evidently not entirely 

 completed on February 2-10. 



Schlosing reports experiments with 114 parts of ammonium 

 chlorid per million of soil in which 88.1 per cent of the ammonia 

 was nitrified in 18 days, and in another experiment, with 526 

 parts of ammonium carbonate per million of soil, 97.7 per cent of 

 the ammonium was nitrified in 28 days. 



The reactions involved in these fixation processes are usually 

 incomplete, mass action being one of the controlling factors. Thus 

 with soil silicates containing much calcium, magnesium, and so- 

 dium, and but little potassium, applied potassium would doubtless 

 be largely fixed, with liberation of calcium or other bases; whereas, 

 heavy applications of calcium sulfate will liberate more or less 

 potassium from soils rich in insoluble potassium compounds. 



