94 



gauge 35.6 lbs. per acre, equivalent respectively to 239, 209 and 228 

 lbs. of ordinary sodium nitrate. This, then, is the amount annually 

 produced (and 1 )St) in land left for many years unmanured, lying in its 

 natural state of consolidation, and receiving no aeration from tillage. 

 All vegetation that appears on these soils is removed." 



Lecture 5. Deals with the " Nitrification of Soils and Manures." 

 In it Mr. Warington points out by means of tables that the greatest 

 loss of nitrogen as nitrates by drainage takes place during those months 

 when the soil is not covered by a growing crop. " In June it is rare to 

 find nitrates in this drainage water. Out of the twenty-five samples of 

 drainage collected in June, July and August during twelve years, only 

 three contained any nitric acid. In September, the crop being now 

 removed, nitrates are always found in the drainage water. In a wet 

 season the maximum amount of nitrates will occur in October. The 

 proportion of nitrates will be maintained with little diminution during 

 the winter months and begin to fall again in March." The crop, there- 

 fore, which has the longest growmg season will be the best to conserve 

 the nitrates in the soil. " From this point of view maize (Indian Corn) 

 is a more economical crop than either wheat, oats or barley, its 

 growing period extending during the whole of the summer." This 

 lecture is brimful of practical information of a most valuable nature, and 

 the inclination is strong to make very copious extracts, but a few more 

 must suffice. Ihe explanation why the cereals more especially respond 

 to the application of soluble nitrogenous manures is given in the follow- 

 ing words : "After a wet winter cereal crops begin to grow in a soil 

 impoverished of its nitrates, and the growth of most cereals is over 

 before the summer production of nitrates is half accomplished. Cereal 

 crops are then especially benefitted by nitrogenous manures, and 

 particularly by the application of nitrates, while for the reason already 

 given, maize is more independent of such manuring than wheat or 

 barley. The beneficial influence of a dry winter upon the crops of the 

 ensuing vear is now generally recognized." Mr. Warington gives 

 scientific reasons for practicing rotation, and shows how a proper suc- 

 cession of crops tends to preserve and use the nitrates. This lecture 

 proceeds to give the loss of nitrates in soils fertilized with different 

 manures and cropped with wheat and barley. He sumuiarizes his 



