PROCEEDINGS OP SECTION K. 671 



No doubt tlie administration of small quantities of these 

 elements to the soil encounters numberless difficulties in practice, 

 no doubt other factors should be taken in consideration, but the 

 results so far obtained may be considered an excellent guide for 

 future work. 



It may be said that it seems extraordinary that so small 

 amounts of these elements may be a condition of success in vege- 

 table life, but we have only to think of the wonderful work per- 

 formed by the roots of plants to see that it is quite possible. 



In the experiments with Aspergillus niger, Raulin found the 

 plant to take zinc from a liquid which contained only 1 /50.000th 

 of it^ seaweeds, as we know, take iodine from a liquid which con- 

 tains it in a dilution of more than 1 in 300,000. Further, Ber- 

 trand (Ootnpt. Reiicl., 1912, 13J^, 616-619) found that very minute 

 quantities of manganese, one part in 10,000,000,000 have an appre- 

 -ciable effect in increasing the yield of Aspergillus niger. 



7. PRELIMINARY NOTE ON SOIL DRAINAGE 

 EXPERIMENTS. 



Bt/ Heher Green, D.Sc. 



Abstract. 



The author renninded members of an experiment carried out at 

 Burnley, a few years ago, from which the conclusion had been 

 drawn that the use of superphosphates as a fertilizer, as practised 

 so extensively in Victoria, would cause depletion of the plant food 

 of the soil. 



As this conclusion did not appear to be justified, a series of ex- 

 periments has been started at the Agricultural Chemistry Labora- 

 tory, at the Melbourne University to determine the actual loss of 

 plant-food in the drainage water of two different types of soil when 

 fertilized by superphosphate, and with other manures. 



The soil is contained in large pots or barrels, each holding about 

 half-a-ton. As these are fitted with drain pipes, and protected 

 from abnormal rains by a glass roof, the conditions can be con- 

 trolled so as to resemble a normal soil in an average season. 



It is not expected that such an experiment can satisfactorily 

 answer the original question until several seasons have elapsed, 

 and up to the present the results show no definite effects of the use 

 of superphosphate. The experiment has, however, necessitated 

 other research work on 'the flow of water through soils, and this 

 has been published during the past two years conjointly with Mr. 

 G. A. Ampt, in the Cambridge Journal of Agricultural Science. 



