Fertility of some Colonial Soils. 17 



stituent minerals of the granite had completely decomposed, and the 

 results of the analysis of this soil were : — 



Lime -281 



Potash -151 



Phosphoric oxide '172 



The averages of the others, which were primary granitic soils, 

 twenty in number, were : — 



Lime -037 



Potash -025 



Phosphoric oxide -014 



It was not, I repeat, that the latter contained less lime, potash, and 

 phosphoric oxide than the former, but that those substances were 

 largely present in the first soil in the condition which I have 

 described as Grade II., whereas in the others the greater part 

 existed as plant-food constituents of the third grade. With this 

 explanation there should be no cause for surprise that most of the 

 nine primary granite soils whose analyses follow are shown as 

 deficient in mineral plant food : — 



III. GRANITE SOILS. 



Serial 

 No. 



Division. 



Farm. 



Fine 

 Earth. 



Water. 



Organic 

 Matter. 



Lime. 



Potash. 



Phos- 

 phoric 

 Oxide. 



26 



George 



Diepkloof 



Alexanderfontein 



»>• 



Vredehof 



Neethlingshof ... 



94-7 

 720 

 73 8 

 800 

 72-2 

 680 

 760 

 61-5 

 691 



■97 

 1-57 

 11.5 

 1-47 

 101 

 109 

 1-28 



•87 

 1-26 



3-51 

 5-83 

 318 

 501 

 4-33 

 2-64 

 4-30 

 3-69 

 405 





028 

 146 

 072 

 096 

 014 

 014 

 014 

 034 

 024 



•034 

 •121 

 •075 

 •095 

 •114 

 •045 

 •095 

 •014 

 •023 



•020 



27 

 28 

 29 

 30 

 31 

 32 

 33 



Malmesbury 

 Paarl 



•061 

 •072 

 •073 

 •049 

 •028 

 •055 

 •055 



34 



Stellenbosch 



•018 



The averages of these soils work out as follows : — 



Lime -049 



Potash -069 



Phosphoric oxide -048 



The result of the partial decomposition of the felspar contained in 

 the granite is seen in the relatively larger percentage of potash when 

 these analyses are compared with those of the clay-slate soils. 



Above the slates of the Malmesbury series, in the Oudtshoorn 

 Division, are what have been termed the Cango beds, consisting of 

 quartzitic pebbles embedded in a slaty matrix, which at some places 

 becomes calcareous. It may be expected that the former type will 

 produce a comparatively poor soil, while a correspondingly better 

 class of soil will be produced where the calcareous matrix prevails. 



2 



