96 CoTiclusions 



extending the application of artificial manures, until at the present 

 time such manuring is coming into its own and is receiving more of 

 the widespread attention that it deserves. The possibility now exists 

 that in some respects the two lines of work are converging and that 

 the more purely scientific line will have a big contribution to make 

 to the strictly practical line. Artificial manuring aims at improve- 

 ment of the soil and crop by the addition of food substances that are 

 needed in a particular soil, a result that used to be obtainable only 

 by the use of the bulky farmyard manure, seaweed, &c. Apart firom 

 any other aspect of the matter the artificials, when intelligently used, 

 are far more easy to handle and to regulate in supply, and they 

 jdeld excellent results, especially in conjunction with a certain pro- 

 portion of organic manures. The farther prospect now opened up is 

 the possibility of utilising some of these stimulating compounds as 

 artificial manures. As only small traces are beneficial, larger amounts 

 being poisonous, it is obvious that only small quantities would be 

 needed, and, as the compounds are not usually very expensive, a con- 

 siderable increase of crop for a relatively small outlay might be 

 anticipated if no complicating factors intervened. Very much work 

 will be required in the field to test the value of these substances, as 

 their action may be influenced by the nature of the soil, climatic con- 

 ditions, general conditions of manuring, and the crops grown. Some 

 tests have already been made, especially in Japan, with boron and 

 .manganese, and these indicate a promising field for investigation. 



Above all, it is most important to realise that one is approaching 

 an entirely unexplored field, and that it is inevitable that the results 

 of the initial experiments will be contradictory, at least in appearance, 

 so that it is necessary to keep an open mind on the subject, being 

 ready to modify one's ideas as circumstances require, as improved 

 experimental methods lead on to more accurate results. 



