PROCEEDINGS OF SECTION K. 673 



Mr. D. McAlpine asked if mushrooms had been grown on steri- 

 lized soil. He had observed that the spawn would only germinate 

 if traces of ammonia were present. 



Dr. S. S. Cameron described an observation when clearing land 

 for lucerne by burning off the scrub, &c., on a small patch. The 

 ashes were removed to a new area, but the increase of growth was 

 observed at the site of the burn, and not where the ashes had 

 been spread. 



Mr. Gabriel stated that when chicory grows in the third-rate 

 soil of Phillip Island, the roots tend to go straight down, but that 

 in the rich soils of otloer districts the roots are stumpy, and remain 

 near the surface. In comparing the work done in different coun- 

 tries, the difference in climate did not always seem to be sufficiently 

 recognised. 



Mr. H. Pye thought that the growth of roots was mainly de- 

 pendent on the distribution of water in the soil. He thought 

 that, as ordinarily used, the superphosphate stimulated the growth 

 of the root stock rather than their tips. 



Mr. H. Wilson asked why was an unmanured crop more 

 drought-resistant than one that had been manured ? 



Professor Watt replied that a soil may be sufficiently fertile, 

 but that when moisture is scarce, the plant may be getting too con- 

 centrated a supply of plant food. 



Mr. D. McAlpine asked if Professor Watt had noted whether 

 the fibro-vascular bundles were affected by superphosphates. With 

 regard to the artificial soils at Burnley which Professor ^ Cherry 

 had referred to as vitiating any experimental work carried out 

 there, he explained that he was not conducting manurial tests, 

 and the fertility conditions v/ere not of so much account as the fact 

 that they were known and recorded. 



Mr. A. E. V. Richardson poinded out that chemical analysis 

 alone sometimes yielded very misleading results, as when they in- 

 dicated that Pinnaroo (South Australia) soils were incapable of 

 being profitably farmed. They had been found to be most profit- 

 able. While the orthodox idea for many years past had been that 

 fertility depended on the chemical, physical, and biological condi- 

 tion of the soil, Whitney and Cameron, of the United States Soils 

 Bureau, had brought the old ideas of De Candolle and Liebig up to 

 date by attributing the infertility of soils to toxic excreta of plant 

 roots and plant residues. They considered that the primary func- 

 tion of fertilizers was not to feed crops, but to neutralize toxins. 

 They further affirmed that soils do not wear out by cultivation 

 and cropping, and that fertilizers are unnecessary where a proper 

 rotation of crops was carried out. These ideas, however, are op- 

 posed to practical experience, and to the best agricultural teach- 

 ing; and tiiey find no confirmation in the results obtained on the 



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