DECAY OF NITUU(JE^'UUS liODIES, '-^9 



From numerous other experiments, not })ublislied at 

 this writing, Ilellriegel believes himself justified in assum- 

 ing that the highest yield thus observed, with 84 lbs. of 

 nitrogen in 1,000,000 of soil, might have been got with 

 70 lbs. of nitrogen in case of wheat, Avith G3 lbs. in case 

 of rye, and with 56 lbs. in case of oats. On this assump- 

 tion he has calculated tlie yield of each of these crops, 

 and the figures obtained (see Table) present on the whole 

 a remarkable coincidence with those directly observed. 



DECAY OF NITROGENOUS BODIES. 



We have incidentally noticed some of the products of 

 the decay of nitrogenous bodies, viz., those which remain 

 in the soil. We may iiov/, with advantage, review the 

 subject connectedly, atid make our account of this ])rocess 

 more complete. 



It will be needful in the first place to give some ex- 

 planations concerning the nature of the familiar trans- 

 formations to which animal and vegetable matters are 

 subject. 



By the word decay, as popularly employed, is under- 

 stood a series of chemical changes which are very differ- 

 ent in their manifestations and results, according to the 

 circumstances under which they take place or the kinds 

 of matter they attack. Under one set of conditions we 

 have slow decay, or, as Liebig has fitly designated it, 

 even <iusis j* wnoieY oi\\Qvs fermentation; and under still 

 others putrefaction. 



Eremecausis* is a slow oxidation, and lequires the 

 constant presence of an excess of free oxygen. It pro- 

 ceeds upon vegetable matters which are comparatively 



'From the Greek, sisnifying slow comhitstion. 



13 



