414 



IXDEX. 



Nutritive substances, proper relative 



proportions of, 127 

 maximum and minimum of, in 



soils, 213 

 minimum of, regulate the crop, 



213 

 effect of the absorption of, in the 



upper layers of the soil, 151 



OAT, food of, derived fi-om arable soil 

 (figure), 204 



— and turnip compared, 39 



— several stages of growth of, 35 

 Oberbobritzseh, unmanui-ed field, pro- 

 duce from, 190 



Oberschona, unmanured field, produce 

 from, 190 



Organic matter in manure does not ar- 

 rest exhaustion, 185 



incorporation of in soils improves 



their physical condition, 89 



Osmosis, laws of, 53 



■pALMS, starch in stems of, 356 



Peas and barley plant, growth of com- 

 pared, 154 



Perennial plant, mode of growth of, 13 



Peruvian guano, composition of, 256 



and ash constituents of seeds, 



difference of, 257 



effect of, due to the presence of 



oxalic acid, 259 



moistened with sulphuric acid 



made more quickly available, 260 



Phosphate of lime, diffusion of in soil, 

 79 



Phosphoric acid and nitrogen, propor- 

 tion between in oats and turnips, 39 



Pierre, analysis of soil by, 311 



Pincus, experiments on clover with gyp- 

 sum, 340 



Plants, annual, biennial, and perennial, 

 vital properties compared, 13 



— anniial, mode of gi'owth of, 17 

 leafy, mode of growth of, 28 



— biennial, mode of growth of, 18 



— perennial, mode of growth of, 14, 26 



— growth of, without nitrogeneous 

 food, 43 



— growth of in turf, 106 

 in solutions of their food, 103 



— underground organs of, 12, 14 



rich in starch, sugar, and giim, con- 

 tain much potash in their ash, 24 



store up food in certain organs for 



future use, 26 



Pools, analysis of stagnant water of, 96 



RTE 



Potash in soils, not always available, 

 248 



— necessary for vegetation, 257 

 Potato, constituents of, 204 



— draws its principal constituents from 

 the arable surface soil, 204 



— effect of the cultivation of, on arable 

 soil, 222 



Poudrette, nature of, 271 



Practical men, 246 



their teaching and practice often 



opposed to each other, 333 



Protoplastcm of wheat plants, propor- 

 tion between nitrogenous and non- 

 nitrogenous substances in, 41 



RADICATION of plants, 9 

 importance of a know- 

 ledge of, 11 . 

 Rape-cake, its composition, 282 

 more diffusible in soils than 



guano, 283 

 its fertilising action illustrated in 



the Saxon experiments, 283 

 Rastadt, soldiers' food and excrements, 



272 

 Restoration, law of, properly interpreted, 



251 

 Rhenish Bavaria, exhaustion of soil of, 



245 

 River waters, analyses of, 371 

 Roots, absorption of miaeral matters by, 



59, 80 



— absorption of food by, not an osmotic 

 process, 43 



— do not offer permanent resistance to 

 the chemical action of salts, 56 



— importance of their developement in 

 cereals, 34 



— mode in which they absorb food, 

 100 



— length of, 11 



— power of selection of food in, 51, 

 55 



— principal conditions for the formation 

 of, 234 



— spread in search of food, 85 

 Rotation, succession of crops in, de- 

 pendent on the cereals, 235 



— system of, does not ultimately in- 

 crease corn crops, 241 



— general results obtained in the Saxon 

 experiments by, 285 



Rye, cultivation of, instead of wheat, 

 shows deterioration of soil, 245 



— sod, 115 



conversion of, into wheat soil, 



123 



