230 president's address — section a (ii.). 



LIVE STOCK ESSENTIAL TO SOIL FERTILITY. 



It is often asked if there is not a certainty in the early future that 

 such soils will become exhausted of their supply of plant iood, and be- 

 come unprofitable. So long as live stock are kept in considerable 

 numbers, this is not likely to happen. I take it that Australian soils- 

 owe their small phosphoric acid supply to the fact that the continent 

 has never been heavily stocked by large animals of any kind. In 

 Victoria we know that previous to settlement by white men the number 

 of kangaroos and emus was much less than the number of sheep is at 

 present. Periodical droughts reduced them in the north ; vast areas 

 were so densely timbered that there was little herbage for them to eat. 

 There were never very many natives in Victoria, but there were quite 

 enough to keep the large animals from becoming numerous on the open 

 plains. Now, the animal is the great factor in concentrating phosphoric 

 acid in the surface layers of the soil. It is true that where no animals 

 are present nearly all the components of the plant are returned to the 

 soil by the process of decay. But the animal stimulates the plant to 

 increased growth. As the flower shoots in particular are browsed o£E, 

 fresh efforts are made to produce a new crop of seeds. Hence more 

 phosphoric acid is drawn up by the roots from the deeper layers of the 

 soil. The animal concentrates the phosphates chiefly in the bones, 

 and when death occurs the bones are slowly but surely incorporated in 

 the earth. In addition, phosphates are being continually returned to 

 the soil in the excrements. The carcass of one sheep to the acre repre- 

 sents the application of 21bs. of phosphoric acid, or about lOlbs. of ordi- 

 nary superphosphates. This quantity does not appear very large, 

 but when the process is repeated year by year for centuries the amount 

 steadily accumulates. As phosphoric acid becomes available in in- 

 creasing quantities the growth of plants of all kinds is stimulated, and 

 consequently more animals can be carried in a given area. Nature's 

 methods throughout all bygone ages are precisely what every thoughtful 

 farmer aims at imitating at the present day. Just as living plants and 

 animals have slowly accumulated the potash and lime from the sea 

 water till they form vast masses of dry land, so the nitrogen and phos- 

 phoric acid have been gradually made available for existing plants and 

 animals by their predecessors throughout all the geological ages. The 

 soils of Victoria are just beginning to be improved by animals. The 

 transformation of the hill country, which is brought about by the intro- 

 duction of Merino sheep, may be studied about Alexandra or Tallangatta, 

 where a few years have already made great changes. Judging by what 

 has already occurred, I think we ma)'' have no misgivings for the fuutre. 



The average chemical composition of Victorian soils as taken 

 from the preceding table bears out the inferences drawn from the 

 examination of soils of various localities. Judged by European stand- 

 ards, the amount of fertility is often small. When it is attempted to 

 make an estimate of the amount of plant food in readily available form 

 (soluble in water or citric acid solution), the results are very disappoint- 

 ing. Yet the practical results are precisely the opposite, and it may 

 well be doubted if any soil in the world is more prolific. The total 

 amount of agricultural products consumed locally and exported is. 



