570 INDEX. 



PACK 



Colloidal clay, amount in soils. Table 84 



analysis of, by Loughridge 385 



effects of alkali carbonates upon 62 



investigation by Schlcesing 59 



properties of .. 61 



separation of, by boiling and kneading 61 



Colloid humates 133 



Colluvial soils : . . . 12 



Colors of soils, advantages of 283 



Common salt, injuriousness in soils 76 



recognition of 76 



removal from soils 76 



Conglomerates 48 



Conifers, tall growth of, in arid regions 517 



Contraction of soils in wetting and drying 1 14 



Co-operation, favored by need of irrigation. 419 



Corsican and maritime pine, ash analyses 520 



Cotton, compact growth and heavy boiling on calcareous soils 503 



Cracking of clay soils in drying 113 



Cressa ; range, tolerance of alkali, figure 545, 546 



Creep 12 



Crops, alkali-resistant 455 



Crumbling of calcareous clays on drying 1 16 



Crumb-structure of soils ; figure no 



Crusting of soils, effects of 111,117, 221 



Cultivated soils, analysis of , 325 



investigation of 316 



Cultural experience the final test 324 



Cutting-out of channels by water-borne gravel 6 



Cypress, different forms of ; figures 507, 508 



D. 



Date palm, resistance to alkali 47& 



Decomposition, chemical, of rocks 16 



Decolorizing action, of soils, charcoal 267 



Deep-rooting of native plants in arid region 174 



Deforestation, effects of 2I 9 



Deltas, formation of 7 



Denitrifying bacteria T 48 



Deserts, effects of winds in ' 8 



Desert sands, only lack water to become productive 420 



Dew, formation of 37 



rarely adds moisture to soils 3^ 



within the soil 3^ 



Differentiation of soil and sub-soil, causes of 121 



Distance between furrows and ditches 241 



Dolomite.. 42 



