774 



Agricultural Journal of Victoria. 



in favor of the fallowed plots. In the fourth instance, however, 

 where a phosphatic and nitrogenous fertilizer has been applied, the 

 yield on the continuously cropped plot is almost equal to that 

 obtained from the fallowed plot, that is, the application of a 

 nitrogenous fertilizer in the one case seems to have played the same 

 effective role as fallowing has in the other. In a season similar to 

 the one under review, the principal benefit to be derived from 

 fallowing appears then to centre in the greater amount of available 

 nitrogen provided for the crop's needs. This fact appears to be 

 brought prominently forward by a comparison of the following 



figures : — 



Average Yield of the Three Fields, 1903. 



From the figures above, applications of a nitrogenous fertilizer 

 appear to have resulted in far heavier gains on the continuously 

 cropped plot than on the fallowed, the increased yield produced 

 being 4^ bushels in the first case, compared with If in the second. 

 The results are of great interest, and may indicate the necessity in 

 the future of considering nitrogen requirements, as well as phos- 

 phatic, in Northern soils. It is quite possible that the exceptional 

 rainfall of the past year may have allowed an operative effect on the 

 continuously cropped ground of a nitrogenous fertilizer, which, under 

 ordinary circumstances, would not have been evident. It is however 

 possible, and perhaps probable, that the nitrogen reserves of our soils 

 may, under a system of continuous cropping with phosphatic manures, 

 soon show signs of exhaustion. An indication of such a thing 

 occurring would reveal itself first in the more marked action of 

 nitrogenous fertilization on continuously cropped ground, and the 

 fields with which we are now dealing are particularly valuable as 

 offering means for gauging the gradual decline in the stock of nitro- 

 genous plant food which might be taking place. This contingency 

 has been referred to by me on a former occasion, and my remarks, 

 appearing in the Annual Report of the Department of Agriculture for 

 1900-1, may be worth repeating. I there wrote : — 



" The Niteogen Question." 

 " Here, again, we have one of the most interesting problems in 

 the manure question, and one that can be only properly probed by 

 continuous tests over a number of years on the same field, as indicated 

 above. Generally speaking, an addition of nitrogen to our crops in 

 the North results in a very small or no increase in returns, and some- 

 times leads to a reduction in the yield. Such an experience is quite 

 contrary to the European, as clearly brought out in the classical 

 experiments of Lawes and Gilbert, and finds at least one explanation in 



