No. 6. 



DBPARTMiENT OF AGRICULTURE. 



409 



Quantity of Nitrogen in Crops: — A few reliable figures may be 

 quoted and lessons learned therefrom. In the country of France, 

 for instance, the cultivated area has been calculated to be about 

 61,750,000 acres, and the crops grown on this area use yearly 600,000 

 tons of the element nitrogen, but that with the very best of economy 

 not more that 330,000 tons of nitrogen will be returned to the soil 

 in the various manures. We will not be very far wrong if we ac- 

 cept these figures as representative of any country, and if we apply 

 them to our land where we are supposed to have at least five times 

 as many acres under cultivation, five times the quantity mentioned, 

 or 3,000,000 tons nitrogen would be used yearly by the crops of our 

 soil. But since we are on the whole much more careless and waste- 

 ful with our manure nitrogen than most European countries, we can 

 not count on half of the nitrogen being returned to the soil in the 

 form of manure but considerably less. 



Nitrogen Needed in the Soil: — According to Lierke's calculations 

 (Praktisohe Uungertafeln, Berlin 1887), one acre of soil should con- 

 tain, or have so much applied to it, that there should be available 

 for the various kinds of crops the following amounts of nitrogen: 



3 



J? 



Cereals (grrain crops). 



Potatoes 



Fodder beets, 



Turnips, 



Carrots 



Meadow hay 



120 

 187 

 174 

 166 

 165 



With our present methods of farming and knowledge of agricul- 

 tural science in general, we must, for some time at least, in order to 

 obtain the highest possible results, figure on that at least half of the 

 needed nitrogen will have to be applied in the form of bought fer- 

 tilizers to most of our oldest or longest cultivated soils. 



Sources of Nitrogen Available for Fertilizers: — The chief sub- 

 stances used are Chili saltpeter (nitrate of soda), sulphate of am- 

 monia, bone and guano. Of these, sulphate of ammonia is a by-prod- 

 uct in the lighting gas and coke manufacture. The guano beds are 

 the accumulated droppings of birds, and are found on the coast and 

 islands in certain localities in the southern oceans, but the supply of 

 this fertilizer is now practically exhausted. Chili saltpeter is found 

 in beds in the mountainous coast of Peru and Chili, South America. 

 Here the crude salt is mined, purified and prepared for the market. 



Enormous quantities of this Chili saltpeter has been exported 

 during the last thirty years, as can be learned from the following 

 figures, quoted from a publication issued 1906 by the Norwegian Ni- 

 trate Manufacturing Co. The ton referred to- 1,000 kiligrams or 

 about 2,205 pounds. 



In 1860 the export was 

 In 1870 the export was 

 In 1880 the export was 



Tons. 



68,500 

 182,000 



In 1890 the export was 

 In 1900 the export was 



27 



225,000 ' In 1903 the export w^ 



Tons. 



1,025,000 

 1,453,(100 

 1,606,000 



