where the disease had. made its appearance was poorer all round than that 

 oi the virgin soils from the same locality: vide the following: 



Average composition jn-r ccut. of 

 virgin soils. cultivated soils. 



Lime '291 '194 



Potash -133 -127 



Phosphoric oxide '031 '015 



This shows to some extent the soil exhaustion that had taken place : 

 the crops were apparently badly in need of phosphatic material, and it 

 would not be surprising if this had a great influence upon their capacity to 

 resist the attacks of parasitic diseases. 



In this connection I may aptly quote Professor P. MaoOw&n, D.Sc., 

 F.L.S., formerly Government Botanist, who was professionally investigating 

 the fungus disease at the time when the analyses just mentioned were being 

 made. Dr. MacOwan observed : 



"Phosphate of lime is the one thing needful as mineral food for all cereals 

 wheat, barley, oats, mealies, and rye. Yet, beginning with a poor supply of it,* 

 there are hundreds of farms where cereals have been taking the phosphate out of the 

 soil every year for a quarter of a century. The inevitable result has come about. 

 Stinted in phosphates, the corn grows year by year more weakly in constitution, stools 

 less, gives lighter ears, gives shrivelled grain. All this is the naturai result of 

 phosphate starvation. On such debilitated plants the parasitic fungi and insects make 

 their usual attacks. The plants have so little vitality that they cannot bear the 

 injury and live. Naturally they succumb. The cure is restoring the original per- 

 centage of phosphates, to make the land what it was before five and twenty crops 

 had each carried away a share of this element of its fertility." 



On comparing the Koeberg soils with those around Durbanville, it will 

 be observed that many of the latter contain more available lime than the 

 former do. The reason hereof has not yet been investigated : the underly- 

 ing rock being in both cases of the same nature, it appeared improbable 

 that this could have anything to do with the variation. Posaibly the 

 larger proportion of lime in the more southerly soils was due to the finely 

 divided pao-ticles of blown searsand, which extend across the Cape Flats 

 from the southern coast. 



CARNARVON. 



(Privately collected.) 



No. Field Cornetcy. Farm or place. Collector, 



1. No. 5. Jakhals Kolk. C. McMillan. 



o 



* >j 



These two soils were collected respectively from Lots 111 and 94, near 



Tan Wyks Vied. The former had been under cultivation for 17 years, 



but the latter was virgin soil. As they will be dealt with more fully in 



* The italics are my own ; notice the small amount of phosphoric oxide in the 

 virgin soils. 



