Iiide 



X 



Absidia glauca, 328 



Acetic acid, 300 



AciditN', effect of, 242, 289, 299, 300, 

 301 



Acrostalagmus, 83, 278 



Actinomyces, 82, 167, 175 



A. imjricue, 220 



A. poolensis, 290 



A. thennopliilus, 71 



Actinoinycetales, 60 



Actinomycetes, 23, 34, 35, 39, 47, 53, 

 55, 77-82, 252, 270 

 production of antibiotics by, 75 



Actinophage, 279 



Aeration, effect of, 62, 113 



Aerobacter, 60 



A. aerogenes, 193, 268, 270 



Aerobic nitrogen-fixing bacteria, 194- 

 200 



Agarictis nebularis, 121 



Agar-plate method, 39 



Age of plant, 103 



Aggregation of soil, 326, 329 



Agronomical phase of soil microbiol- 

 ogy, 4 



Alfalfa, and soil aggregation, 327 

 decomposition of, 155, 158, 306 



Algae, 36, 56, 88 



nitrogen fixation b\ , 193, 200 



All-crop inoculaiits, 324, 338 



All-soil inoculants, 331 



Altemaria, 83, 328 



A. tenuis, 278 



Amanita ovoidea, 86 



A. virosa, 86 



Amine formation, 167 



Amines, effect on nitrification, 182- 

 183 



Amino acid decomposition, 167-168 

 effect of, 175 



Ammonia, formation ot, 18, 19, 63, 

 108, 118-119, 137, 167, 168, 170, 

 172-178, 188 



oxidation of, 13, 62, 181 

 Ammonia-oxidizing organisms, 181 

 Annnonification, 176 

 Amoebae, 91, 92 



in soil, 55, 56 

 Anabena, 199, 200, 220 

 Anaerobic bacteria, 73 



cellulose decomposition, 74—75 



nitrogen-fixing bacteria, 184, 193- 

 194 

 Animal forms, 37 



pathogens in soil, 282 



residues, 95, 149 

 Antagonistic effects, 38, 261, 266-269 

 Antagonistic fungi, 267 

 Antibiotics, 25, 269, 272, 274-280 



effect on plants, 334 



in soil, 280 

 ApJuniomt/ccs lacvis, 287 

 Aphclcnchus olesistns, 290 

 Armillaria, 278 

 Arsenic, 243, 299 

 Artificial manures, 313-317 

 Ascomycetes, 54, 83, 287, 341 

 AspergiUus, 23, 38, 54, 65, 83, 85, 86, 



110, 239, 278, 342 

 A. clavatus, 278 

 A. fiavus, 278 

 A. fumigatus, 243 

 A. nidulans, 328 

 A. niger, 88, 174, 175, 177, 239, 268, 



269, 278, 328, 329 

 A. ochraceus, 243 

 A. oryzae, 110, 239 

 A. sijdowi, 243 

 A. tcrricola, 167 



347 



