Journal of Agriculture, Victoria. [ii Nov., 1912. 



they are fixed in the soil and prevented from becoming lost. This is 

 borne out by the investigations of Dyer in the permanent plots of the- 

 Rothamsted experimental station. Dyer's results show that practi- 

 cally no loss of phosphoric acid has taken place on the plot heavily- 

 manured with super, for over fifty years. 



It is often asked whether the continual use of superphosphate will 

 impoverish or exhaust the soil. Real soil exhaustion, of course, can 

 never take place. Bad farming practices, however, may reduce the 

 fertility of the soil to such a low level as to render cropping operations 

 unprofitable. For practical purposes we say that such a soil is ' ' worn 

 out " or " exhausted. ' ' 



Now, the repeated use of superphosphate will not bring about any 

 such soil exhaustion, if the farm operations are intelligently conducted. 

 The continued use of phosphates will merely bring about a state of 

 things in which further applications of phosphate will no longer prove 

 profitable. The soil will not, however, be exhausted. It will merely 

 contain an excess of phosphates, and it may then be necessary to apply 

 other manures such as nitrates in order to maintain production at a 

 high level. 



In soils deficient in lime, the continual application of heavy 

 dressings of superphosphate may cause the soil to become acid or sour 

 in character, thus impairing vegetation. In such cases, however, this 

 acidity may be corrected by suitable applications of lime {vide Journal 

 of Agriculture, Victoria, October, 1912). 



Time and Mode of Application. — In the majority of seasons the best 

 results are obtained with superphosphate when the seed and manure 

 are drilled in together in the normal seeding season. 



Many farmers frequently sow the manure some weeks before seeding,, 

 either by means of a cultivator with a drill attachment or with the- 

 ordinary fertilizer drill. The cost of cultivation is slightly increased 

 by sowing the seed and manure in two operations, but a compensating 

 advantage is perhaps gained at seed time by the expediting of seeding 

 operations. This is sometimes a matter of importance, especially 

 where the seeding is likely to be delayed by want of strength, or by 

 not having the land properly prepared. 



The advantage of sowing seed and manure together is that the young 

 plants very readily find the manure and make vigorous growth early 

 in the season. They thus become well established and develop a good 

 root system before the winter sets in — a point of great importance in 

 relatively dry districts. If the autumn has been unfavorable to the- 

 destruction of weeds, the sowing of seed and manure gives the young 

 crop a decided start, and materially assists it in overcoming the weeds. 



Basic Slag. 



This is obtained as a by-product in the manufacture of steel 

 from iron ores rich in phosphorus. It is sold as a fine, heavy 

 black powder. It is a very popular manure in Europe, both for wheat 

 crops and for the improvement of pastures. It contains from 15 to- 

 18 per cent, of phosphoric acid, and about 40 per cent, of lime. 



In the wheat areas it is used at present only in relatively small 

 quantities, and experience proves that, though a valuable manure, it 



