570 



INDEX. 



FACE 



Colloidal clay, amount in soils. Table 84 



analysis of, by Loughridge 385 



effects of alkali carbonates upon 62 



investigation by Schloesing 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 114 



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 in, 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 478 



Decomposition, chemical, of rocks 16 



Decolorizing action, of soils, charcoal 267! 



Deep-rooting of native plants in arid region 174 



Deforestation, effects of 219 



Deltas, formation of 7 



Denitrifying bacteria 148 



Deserts, effects of winds in 8 



Desert sands, only lack water to become productive 420 



Dew, formation of 307 



rarely adds moisture to soils 308 



within the soil 308 



Differentiation of soil and sub-soil, causes of 121 



Distance between furrows and ditches 241 



Dolomite . . 42 



