1036 



INDEX 



Soil, bacteria, unproductive soil, 367 



in water, 312 

 bacterial substance available, 398 



substance present, 397 

 biological factors of soil-forma- 



tion, 417 



calcium, 374, 417 

 carbohydrates (origin), 375 

 carbon dioxide in, 351 

 carbon-nitrogen ratio, 382 

 climatic influences, 352 

 colloidal nature of, 349 

 composition (mechanical), 250 

 copper, 425 

 culture medium, 346 

 cultures for soil, 414 

 denitrification, 395 



environmental relations, 396 



experimental study, 395 

 drought, 348 

 early, 353 

 fermentations, cellulose, 362, 375 



fats, 378 



fixation of nitrogen, 400 



organic matter, 345 



proteins, 380 



starches, 378 



sugars, 378 



waxes and gums, 378 

 food (plant) assimilation of, 354 



(plant) production in, 354 

 formation of, 417 

 general discussion, 345 

 higher plants in, 367 

 hydrogen ion concentration, 356 

 infection, 666 

 inoculation, 412 

 iron, 425 

 late, 353 



magnesium, 374, 417, 419 

 manganese, 425 

 medium, as culture, 290 

 mineral food, 358 

 mineralization of organic matter, 



moisture relations, 346 



Soil, moisture, excessive, 348 

 rainfall, 346 

 range of, 347 



molds in, 360 



nitrates, transformation of, 398 



nitrification, 389 



bacteria (nitric and nitrous), 



390 



environmental relations, 391 

 experimental study, 389 

 nitrates, accumulation, 394 

 disappearance, 394 



nitrogen, addition of, 374 

 utilization, molds, 362 



nitrogen (atmospheric) fixation, 



aerobic species, 362, 402 

 anaerobic species, 402 

 biological relations, 401 

 chemical relations, 401 

 cultures for inoculation, 414 

 development of organisms, 408 

 energy relations, 404 

 entrance of organisms, 408 

 environmental relations, 410 

 inoculations, methods of, 412, 



414 



mechanism, 410 

 physiological efficiency, 409 

 resistance of plants to, 409 

 specialization of organisms, 410 

 symbiotic, history of, 405 

 symbiotic (non), history of, 401 

 theories of, 400 

 variations of, 410 



nitrogenous compounds, transfor- 

 mation of, 398 



organic acids, accumulation of, 380 

 source of, 379 

 transformation of, 380 



organic matter in, 358 



origin of, 417 



carbohydrates in, 375 

 fats, 378 

 waxes, 378 



oxidation of carbon, 351, 373 

 carbon monoxide, 377 



