INDEX OF SUBJECT MATTER 



581 



Partial analysis of soils, digestion with 

 dilute acids, objections, 318. 



digestion with dilute acids, value, 

 318. 



digestion with strong acids, 316. 



digestion with strong acids, objec- 

 tions, 316. 



extraction with water, 319. 



extraction with water, method of, 

 321. 



extraction with water, value, 322. 



of Minnesota soils, 316. 



of Minnesota and Maryland soils, 

 317. 

 Partially decomposed matter of soils, 105. 

 Particles of soil, number to a gram, 96. 

 Peat, agricultural value of, 43. 



capillary capacity of, 164. 



character of, 43. 



chemical analysis of, 44. 



term defined, 43. 

 Percolation, control of, 208. 



Cornell data, 209. 



effects of crops on, 210. 



loss of nutrients by, 208. 



in arid regions, 208. 



in humid regions, 208. 



Rothamsted data, 207. 

 Ph values of acidity explained, 350. 

 Phosphate fertilizers, acid phosphate, 

 456. 



basic slag, 457. 



bone phosphate, 454. 



relative availability of, 458. 



rock phosphate, 455. 

 Phosphoric acid, amount of in acid phos- 

 phate, 456. 



amount of in apatite, 6. 



amount of in basic slag, 457. 



amount of in igneous rocks, 6. 



amount of in manure, 501. 



amount of in bone, 454. 



amount of in rock phosphate, 455. 



amount of in soils, 12. 



forms of in fertilizers, 456. 



forms of in soil, 11. 



influence of green manures on, 545. 



influence of lime on reversion of, 

 373. 



influence on plant growth, 474. 



in liquid and solid manure, 503. 



loss of from farm manure, 519. 



Phosphoric acid, loss of from soil, 555. 

 losses from Cornell soils, 307. 

 of food recovered in farm manure, 



516. 

 of soil, 140. 



organic and inorganic in soils, 315. 

 organic nature of, 11, 314. 

 pounds removed by various crops, 



468. 

 relative availability of in fertilizers, 



458. 

 Phosphorus, see phosphoric acid. 

 Physical absorption by soils, 263. 

 Physiological character of plants in re- 

 lation to alkali toxicity, 336. 

 Piconometer, for determination of specific 



gravity, 90. 

 Plankers, action of, 148. 

 Plants, absorptive activity of as deter- 

 mined by certain factors, 299. 

 acquisition of nutrients by, 291. 

 alkali vegetation, 340. 

 capacity of to grow on poor soils, 



299. 

 cause of drought resistance by, 195. 

 cause of wilting, 194. 

 detrimental influence of nitrogen on, 



473. 

 differential diffusion into, 292. 

 different absorptive capacity for soil 



nutrients, 301. 

 direct influence of upon soil nu- 



nutrients, 296. 

 effect of alkali on, 334. 

 effect of calcium and magnesium 



ratio on, 376. 

 effects of on percolation, 208. 

 factors affecting transpiration from, 



188. 

 function of water in, 184. 

 growth of in acid medium, 350. 

 influence of on the soil solution, 



284. 

 influence of phosphorus on, 474. 

 influence of potassium on, 475. 

 influence of roots on soil colloids, 



297. 

 influence of soil water on, 186. 

 production of acids by, 296. 

 productions of oxidases by, 297. 

 reduction produced by roots of, 297. 

 resistance of to alkali, 335. 



