219 



Soil, extraction methods, comparison of, 59, 63, 94, 153. 

 fertility, due to various causes, 1. 

 fine state of division requisite, 1, 13. 

 mechanical analysis of : see Mechanical analyses, 

 moisture, the medium for feeding plants, 3n. 

 physics, 5, 10, 11, 42. 

 particles, source of plant food, 1. 



rounding of before analysis, gives misleading results, 13. 

 sa ^ples, choosing of, 6, 157. 



collection of, 6, 19, 20. 

 ,, preparation of, for analysis, 6. 

 survey carried on single-handed, 4, 19. 

 commencement of, 4. 



object of, to ascertain reserves of plant food, 10. 

 equipment for, 19. 

 of Arkansas, 11. 

 ,, Kentucky, 11. 

 origin of, 3. 



should include only virgin soils, 6, 54. 

 ,, stopped by war, 4. 

 uniform methods needed for, 5. 

 surveys, Russian, 11. 

 So Is chemically poor cannot be productive, 18. 

 Solvents of plant food, Citric acid, 2, 9, 10, 12, 13. 



Hydrochloric acid, 2, 9, 10, 12, 13. 

 natural and laboratory, 2, 8, 12. 



water, 2, 3, 9. 



Somerset East Division, 20, 22. 121, 

 Sour veld: see also Acid soil, 116, 118, 132, 137, 139, 149. 



,, soils, deficient in plant food, 137. 

 South Middelveld, F.C., 90. 

 Spekboom : see Portulacaria afra. 



Standard method of chemical soil analyses, 6, 7, 12, 13. 

 Steenbok zuuring, 40. 



Stellenbosch Division, 20, 22, 79, 122-126, 155, 157, 198. 

 Steynsburg and Colesberg soils compared, 128. 



Division, 20, 22, 126-128, 155, 180-184, 199. 

 Stockenstrom Division, 20, 22, 128. 

 Stormberg and Uitenhage series soils compared, 170. 

 geological series, 52, 53, 128, 168, 169. 

 Range, 146. 



series soils, analyses of, 169, 171. 



,, ,, ,, water retaining capacity of, 171. 



Stow, G. W., 141, 143, 161. 

 Stuurman, F. C., 108. 



Suitability of soils for specific crops, Reasons for, 192. 

 Sulphuric acid as a solvent, 12. 

 Sulphur waters, 54. 

 Sundays River, 136. 



beds, 137. 

 Swellendam Division, 4, 19, 22, 29, 30, 32, 38, 112, 115, 120, 129-134, 139, 154, 164, 



165, 166, 171. 

 Systematic investigation of Cape soils : see Soil survey. 



Table Mountain and Bokkeveld series soils compared, 165. 



geological series, 24, 30, 36, 37, 42, 51, 56, 57, 59, 64, 68, 75, 92, 93, 

 98, 99, 100, 115, 134, 139, 147, 148, 149, 150, 152, 155, 157, 

 163, 164, 167, 168, 171. 



series soils, average proportions of fine earth in, 196. 



chemical analyses of, 164, 171. 



low water retaining capacity of, 171. 



Taungs, 20, 26, 142, 143. 



Texture of soil, an indication regarding fertility, 41. 

 Thaer, 1. 

 Thebue, 127, 180-184. 



soils compared with Calif ornian alkali soils, 182. 



mechanical analyses of, 199. 



water from, analysis of, 183, 184. 

 Thomas River, 47. 



