INDEX. 



587 



PAGB 



Tennessee and Kentucky, vegetation and soil-character 513 



Terraces, river and lake 14 



Testing penetration of irrigation water 242 



Textile plants, tolerance of alkali. 475 



Thomas or basic slag 64 



Thurman's physical theory of plant distribution. 519 



Tillage ; effects of ; figure 109, 1 10 



how maintained in nature in 



Titanium in soils xxxi 



Time of acid-digestion, different ; table 342 



Tolerance of alkali by culture plants 463 



alkali plants ; table 548, 549 



Topography, influence of, on climate 293 



Trachytes 53 



Trona, Urao 77 



Tropical soils 398 



are highly leached 400 



often highly colored with iron 400 



do not need early fertilization 399 



humus in ; abundant, but low in nitrogen 399 



few determinations made 399 



possible calculation of 399 



investigations of 401 



laterites, not always rich in iron 400 



mostly have low plant-food percentages 400 



resemble the " nimble penny." 400 



Tubercles of legumes, figures 151, 154 



Tufa, calcareous 41 



Tussock grass, food value of 470 



range, alkali-tolerance, figure 536, 537 



U. 



Ulmin substances 122 



Underdrainage, advantages of 235 



Underdrains, effects of 234 



Unhumified organic matter does not nitrify , 148 



Unhumified vegetable matter, utility of 135, 360 



United States, good field for comparative soil study . 524 



Upland and lowland growth in arid and humid regions 515 



Usar lands of India, character of 440 



not all alkali lands 440 



V. 



Vegetative belts, lime a governing factor of 492 



Virgin lands, advantages of soil study in 318 



Virgin soils, analysis by extraction with strong acids 340 



Vi vianite 65 



