president's address — SECTION G (ii.)- 231 



valued at over £20,000,000, or an average production of nearly £400 

 per farm. As only one acre out of every eight of the occupied part of 

 Victoria is at present under cultivation, the above results are achieved 

 to a very large extent simply by grazing the natural pastures. The 

 soils from Mildura, in the Mallee, are much below the average in phos- 

 phoric acid and nitrogen, yet under irrigation 10,000 acres support a 

 population of 5,000, or 330 persons to the square mile. Here again 

 development is just beginning, for with the application of more labor 

 the returns from the irrigated land could be vastly increased. From 

 the strictly chemical point of view, much of the wheat land appears to 

 be in danger of early exhaustion, yet after many years of grazing and 

 cropping it is more valuable than ever. Similar instances could be 

 quoted from every part of the State. Another point which must be 

 remembered is the fact that nearly all the cultivation in Victoria is 

 found in districts with a comparatively light rainfall. 



Reverting to the total weight of each ingredient present in the 

 surface foot of each acre, it will be seen that rich soils contain in this 

 amount of soil 3| tons of nitrogen, 3 tons of phosphoric acid, and 

 8J tons of potash. One of the poorest contains 1 ton of nitrogen, 

 6cwts. of phosphoric acid, and 9cwts. of potash. As a 20bush. crop 

 of wheat (straw and grain) removes only 351bs. of nitrogen, 141bs. 

 of phosphoric acid, and 251bs. of potash, it will be seen that even 

 poor soil contains materials for generations of cropping if the proper 

 ingredients can only be made available. The phosphoric acid would 

 last about 48 years. There is, however, the subsoil to draw on, and 

 we have seen that phosphoric acid is nearly as abundant in the 

 subsoil as in the surface. With intelligent farming there is no ques- 

 tion but that the amount of plant food will steadily increase. The 

 striking results produced by the application of lOlbs. of phosphoric 

 acid in the form of superphosphate has been already referred to. Such 

 a small amount cannot perceptibly increase the total per acre. At 

 the most, it can only give the young plants a good start, because, from 

 what we know of the rasidual effects of such applications, it is fairly 

 certain that the whole of the added phosphoric acid is not absorbed 

 by the growing crop. There must, therefore, be certain changes going 

 on in the soil during the growth of the crop which rapidly render the 

 latent plant food available. What these are we are not in a position 

 at present to state precisely. The marvellous growth that occurs 

 everywhere when the rain comes after a dry spell shows that there are 

 forces at work during the months of bright sunshine which are very 

 friendly to the husbandman. The fact that apph cations of nitrogen 

 actually reduce the yield in the northern plains confirms this view. 

 Many acres of the poor sandy soils within 20 miles of Melbourne are 

 bought and sold at from £20 to £40 per acre, after they have been under 

 cultivation for a few years, and where such improvement is dailv taking 

 place it IS certain that it will follow on the same methods being applied 

 to more remote districts as population increases. The absence of land 

 animals accounts at once for the luxuriance of our primaeval forests, 

 and the scarcity of phosphoric acid on the surface of the soil. Had 



