432 



INDEX 



Mechanical analysis, methods of, 



124-128 



or physical analysis, 123 

 Merrill, (. P., composition of feld- 

 spars, 3 

 expansion of granite by hydra- 



tion, 21 

 glass ground by wind-borne 



sand, 19 

 table, chemical analyses of 



loess, 05 

 on lo.ss of constituents of 



rocks, 25 



physical analysis of dust, 64 

 Merrill, L. A., yield of wheat for 

 different depths of plow- 

 ing, 245 



methods of seeding, 254 

 Metamorphic rocks, 10 

 Methods of soil survey, 118 

 Mica, black, biotite, 4 



white, muscovite, 4 

 Micro-organisms, injurious, 317 



beneficial, 317 

 Migratory sand dunes, 58 

 Miller, M. F., plant food in Mis- 

 souri soils, 392 

 Mineral colloids, 132 



constituents of soils, chapter 



on, 123 



content of soils, 74 

 phosphorus-bearing, apatite, 5 

 soil constituents and their prop- 

 erties, 129 

 Minerals, dissolved by carbonated 



water, 22 

 hardness of, 2 



iron-bearing, hematite, magne- 

 tite, limonite, 5, 6 

 soil forming, 1 



specific gravity of, 175 

 Minor crops, 376 



Mississippi River, soil material de- 

 livered at mouth, 35 

 Moisture, available, 214 



increased by drainage, 223 

 capacity of soil, methods of in- 

 creasing, compacting 

 soil, 230 



deep rooting crops, 231 

 organic matter, 231 

 tillage, 230 

 control of, chapter on, 222 



by tillage, chapter on. 230 

 content, ways of expressing, 191 



Moisture content, ways of express- 

 ing, acre-inches, 192 

 cubic inches, or per cent 



of volume, 192 

 per cent of weiglut of 



soil, 191 

 decreasing, losses from soils, 



232 



effect of, on specific heat, 300 

 equivalent, defined, 202 



determination of, from other 



constants, formulae for, 203 



equivalents of some soil classes, 



202 



excess of, removed by tillage, 231 

 factor in amount of organic 



matter in soils, 143 

 soil classification, 73 

 for bacteria, 319 

 -holding capacity of soils, 209 

 hygroscopic, chapter on, 194 

 in soil columns, 201 

 retained by organic matter, 149 

 storing and conserving by till- 

 age, 326 



supply in soils, 189 

 Moraine, terminal, 43 

 Morrow, G. W., results of root prun- 

 ing in shallow and deep cultiva- 

 tion of corn, 355 

 Moss, sphagnum, 28 

 Mucks, 114 



specific heat of, 300 

 Mud flow, Colorado, 34 

 Miiller, Richard, solution of min- 

 erals, 22 



Mulch, defined, 233 

 depth of, 235 

 fineness of, 234 

 maintenance of, 236 

 soil effectiveness of, 235 

 value of, for corn, humid re- 

 gions, 350 

 Mulches, permit little loss of water 



by interstitial evaporation, 233 

 Muscovite, white mica, 4 



Xebraskan glaciation, or .Terseyan, 



46 

 Nelson, J. B., with Atkinson, storing 



rainfall, Montana, 248 

 Newell, Dr. F. H., directed large 



irrigation projects, 258 

 Nitrates lost from soil by leaching, 



322 

 by denitrification, 323 



