NITRIFICATION IN ARABLE SOIL 



p. V. Deheraix. 



THE EFFICACY OF NITRATES. 



In 1850 Boussingfanlt aud Georges Ville- almost at the vsame time 

 clearly observed the marked effect which nitrates exert on the develop- 

 ment of plants.' The experiments of Boussingault were particularly 

 convincing. Ue prepared a sterile soil of sand and gravel, to which he 

 added the mineral substances necessary to plant growth and planted 

 suntlower seeds in it. In case of those receiving mineral fertilizers 

 alone the young plants after drying weighed only 0.507 gm. They 

 attained a weight of 0,88 gm. when the sand on which they grew 

 received 0.02 gm. of nitrate, 1.24 gm. when 0.04 gm, nitrate was 

 applied, and 3.39 gm. when the amount of nitrate was increased to 

 O.IG gm. 



More recently Hellriegel has continued experiments in this line on 

 barley. The yield of dry matter varied from 0.415 to 0.508 gm. when 

 the sand in which the barley was planted received no nitrate of lime. 

 It increased as the quantity of nitrate of lime applied increased, reach- 

 ing 10.805 gm. when 0.65G gm. of nitrate was applied, 16.388 gm. with 

 0.984 gm., and finally 29.343 gm. with 1.9<>8 gm. of nitrate. 



It IS hardly necessary to i)oint out that Europe imports annually 

 500,000 tons'^ of nitrate of soda, which is brought from the deposits 

 along the coast of the Pacific in Peru, Bolivia, and Chile. Evidently 

 this industry would not assume such large proportions if the great value 

 of nitrate in agriculture was not appreciated. 



In France at the i)resent time the growers of beets always supple- 

 ment* the regular application of 20 to 40 tons of barnyard manure per 

 hectare with 150 to 200 kg. of nitrate of soda. 



It is not without surprise that we note the necessity for tliis constant 

 applicatiim of nitrogenous fertilizers; for, as Liebig i>ointed out more 

 than 50 years ago, ordinary soils contain considerable amounts of 

 nitrogen, not infrequently 1 to 2 parts per thousand. If we assume 

 that the roots of our ordinary plants go down only to a depth of 35 



' In the seventeenth century certain observations had been made on this subject. 

 Dy.ijlie had observed that saltpeter exerted marked iuHuence on the <,nn\vth of liemp. 

 Also in 1851 the Prince de Sahn Horstmar observed that nitrates favored thegrowtli 

 of oats. 



^The metric ton used here and elsewhere in this article is equal to 2,204.6 lbs. 



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