SUBJECT INDEX 



405 



Subsoil, distinction from surface, 332 et 

 seq. 



— effect on fertility, 332. 



— water, possible supply for plants, 



221. 

 Sugar, effect on soil, 201. 

 Sulphates and plant growth, 76. 

 Sulphocyanides, effect on plant growth, 



85. 

 Sulphur cycle in soil, 211. 



— dioxide, harmful effect on plant 



growth, 82. 



— in plants, more than formerly sup- 



posed, 76. 

 Sulphuretted hydrogen, effect on plant 



growth, 85. 

 Sulphuric acid and plant growth, 82, 268, 



bacterial action in soil, 268. 



Superphosphate as fertiliser, effect on 



agriculture, 65. 

 Surface of soil, caking of, 108. 

 Suspensoids, 160. 

 Swamp soils, 212. See also Paddy. 



air supply to plant root, 256. 



changes during green manuring, 



213. 



denitrification and manuring, 210. 



toxic compounds in, 210, 248. 



Swelling of soil when wetted, 133. 



TCHERNOZEM, 3IO. 



Temperature and assimilation, 34. 

 enzyme action, 37. 



— coefficient for cell growth, 35. 



— effect on plant growth ; qualitative, 



45. 46, .53. 

 quantitative, 34. 



— of soil, 229. 



effect on bacterial numbers, 



272, 276, 286. 



lowered by clay, 106. 



relation to air temperature, 



231. 

 bacterial activity, 272, 



276. 



— optimum conditions for growth, 53. 



— physiological effects, 54. 

 Texture of soil as affected by calcium 



carbonate, 117, 

 organic matter, 



132. 

 Tilth and compound particles, 106, 171. 



— TuU on, 5. 



Topographical position and soil pro- 

 perties, 302. 

 Torf, 136, 137. 

 Toxic effects of salts, 78. 



reduced by calcium ion, 



78. 



Toxic effects of salts reduced by sugar, 



79- 



— salts in soil, treatment of, 85, 117, 

 Toxins in soil, 173, 244 et seq. 

 Transpiration and concentration of 



nutrient solution, 238. 



— coefficient, 46 et seq. 



Tull's method of crop production, 5, 



Underground water supply and soil 



fertility, 331. 

 Unfavourable seasons, value of potassic 



fertilisers in, 71. 

 " Unfree " water in soil, 226. 



Valleys, fertility of, 332. 

 Vegetation, effect on soil formation, 93. 



— relationships ; effect of soil, 301 



et seq, 



— — other factors, 301 et seq. 



— type of, effect on soil, 302. 

 Vigour of plant affected by calcium, 74. 

 potassium supplies, 70. 



Warping, 308, 315. 



Waste land, 327. 



Wasted fertility, 321. 



Water consumption by plant, 47. 



effect of manures, 48. 



meteorological con- 

 ditions, 47, 



soil conditions, 46. 



water supply, 48. 



— cultures, method of : Knop, ig. 



Modern, 356, 



— Woodward (1699), 4- 



— evaporation from soil, 166 et seq. 

 Keen's equation, 167. 



— holding capacity of soil, 223. 



— in soil, coefficients, relations between 



various, 226. 



— continuity of state, 224. 



determination of, 348. 



supposed various states, 166. 



volume of, 220. 



— retention by soil, 166. 

 magnitude of forces de- 

 termining, 225. 



— supplyand interpretation of mechani- 



cal analysis, 329. 



— — effect on leaves, 44. 

 plant growth ; qualitative, 



43- 



quantitative, 38. 



roots, 44 



seed formation, 44. 



influence in determining value of 



manures, 64. 

 in soil, 218, 301, 



