PROCEEDINGS OF SECTION K. 645 



I do not wish to press this point further, but simply to accen- 

 tuate my statement that the composition either of the crop or of the 

 soil is not an infallible guide to the nature of the manuring re- 

 quired. In fact, we have not advanced much on the principles 

 enunciated by Ville. We still manure with a complete manure, 

 paying special attention 'to the ingredient which is ' ' dominant 

 for the particular crop. * 



Explanations of these peculiarities will, no doubt, be forthcom- 

 ing. In the case of leguminous crops, we are acquainted with the 

 process by which they obtain the required nitrogen from the air, 

 and are independent of soil nitrates or nitrogenous manuring. 



In the case of wheat, I have suggested an explanation, which I 

 venture to think is the correct one, to explain the rather extraordi- 

 nary phenomenon that the application of nitrate or other nitro- 

 genous manure, which is essential to the production of wheat in 

 Europe and America, is without effect on crops grown locally, its 

 place being taken by superphosphate. {Agricultural Gazette, New 

 South Wales, vol. 17, p. 295.) Shortly stated, this explanation 

 lies in the different conditions as to nitrification prevailing here and 

 in Europe and America during the growth of the crop. In these 

 countries, the wheat commences to grow in soil from which the 

 nitrates have been washed out, and in which nitrification does not 

 take place until the crop is approaching maturity. With us, nitri- 

 fication is active and progressive during the early growth of the 

 wheat plant, and nitrogenous manuring is unnecessary, all that is 

 required being the application of a fertilizer which promotes the 

 development of the root-system, a quality which appears to be 

 possessed in a high degree by superphosphate, thus insuring the 

 young plants a vigorous start. 



It has been further shown by J. W. Paterson and P. R. Scott 

 {Journal of the Department of Agriculture, Victoria, vol. 10, p. 

 393) that superphosphate appreciably increases the nitrification of 

 ammonia, indicating that in some cases the addition of phosphates 

 may help to nourish the nitrifying organisms as well as the crop. 



We will now review shortly some of the recent work which has 

 shown that the growth of plants is affected by causes other than 

 lack of plant-food or unfavorable mechanical soil conditions, and 

 which encourage us to look to other remedies for infertile condi- 

 tions. 



We shall see, incidentally, that fertilizers may have an action 

 upon the growth of the plant which is altogether independent of its 

 power of supplying plant-food, and which has, untU recent years, 

 been quite overlooked. 



