90 FOOD FOR PLANTS 



largest in the world having been 52 tons of cane per 

 acre in 1923, and compares to an average for the 

 world of less than one-half that amount. Our pro- 

 duction in Louisiana is about 1 1 tons per acre. 



A comparison of our crop yields with those of Ger- 

 many has been recently made by O. E. Baker of the 

 U. S. Department of Agriculture. The yields per 

 acre in Germany were indicated as being nearly 

 double those of this country. The differences are 

 believed to be due in large measure to the greater 

 proportions of Nitrogen used by German farmers. 

 It is calculated * that European farmers use on an 

 average 600 pounds per acre of a fertilizer carrying 

 4^ per cent, of available Nitrogen, whereas Ameri- 

 can farmers use on an average in their fertilizer prac- 

 tice about 300 pounds per acre of fertilizer containing 

 about 3 per cent, of Nitrogen. The German practice 

 is more logical since it corresponds more nearly to re- 

 storing to the soil the essential elements of fertility 

 removed by crops and lost by means of natural agen- 

 cies. Without doubt American practice is slowly 

 approximating European practice and ultimately we 

 shall see larger use by American farmers of available 

 Nitrogen. Whether it will take place to a great ex- 

 tent by increasing the content of available Nitrogen 

 in mixed goods or by the supplementary use of 

 Chilean Nitrate of Soda, remains to be seen. 



It is certain that our exports of cotton seed meal 

 and cereals carry out of our country each year a vast 

 tonnage of Nitrogen which will have to be replaced. 



* A large proportion of European farmers, especially the more intelli- 

 gent, use fertilizer simples in preference to mixtures. The total con- 

 sumption of fertilizer simples and mixtures all told if calculated to an 

 average would disclose an equivalent for comparison on an American 

 basis as above indicated. 



