Index 



363 



forms, 53; conditions which 



modify, 57. 

 Nitrogen gatherers, 128; nitrogen 



consumers, 128. 

 Nitrogenous matter in phosphatic 



materials, 62 et seq. 



Oats : fertilizer constituents con- 

 tained, 16; in rotation, 222 ; green 

 forage, 265. 



Oats and peas, 266. 



Okra, 306. 



Onions, 29. 



Oranges, 325. 



Orchard fruits and berries: differ 

 from general farm crops, 308; 

 soil considerations, 311; fertiliz- 

 ing in general, 312; apples, and 

 pears, 314 ; peaches, experiments 

 and results, 318 ; plums, cherries, 

 apricots, 325; citrous fruits, 

 325; small fruits, 326; cran- 

 berries, 329. 



Orchard grass, 267. 



Organic nitrogen : defn., 23,'' 37 ; 

 various forms in use, 37-47; 

 availability, 47. 



Oxy-acetylene residue, 118. 



Oyster-shell lime, 139. 



Palmaer phosphate, 74. 



Parsnips, fertilizer constituents in, 

 16. 



Peaches, 318 ; experiments at New 

 Jersey Experiment station, 318. 



Peanuts, 354. 



Pears, 314. 



Peas : field truck, 258 ; green forage, 

 266 ; cowpea, 271 ; market gar- 

 den, 296. 



Peat, 107. 



Pebble phosphate, 70. 



Peppers, 257, 298. 



Peruvian guano, 45. 



Phosphate of lime, 62, 81. 



Phosphates : organic substances, 

 62 et seq.; mineral phosphates, 

 68 et seq. ; manufactured phos- 

 phates, 73; sources of phos- 



phoric acid to plants, 75 ; in- 

 fluence of source, 76; of fine- 

 ness, 77 ; of character of soil, 77 ; 

 of kind of crop, 78 ; general use- 

 fulness, 78; comparison with 

 superphosphates, 85. 



Phosphatic materials : phosphate of 

 lime, 62; bone phosphate, 62; 

 animal phosphate, 62 ; raw bone, 

 63; boiled steamed bone, 64; 

 commercial grades of bone, 65; 

 bone tankage, 66 ; bone black, 

 66; animal charcoal, 67; bone 

 ash, 68; Florida rock, 70 ; Cana- 

 dian apatite, 71 ; Tennessee, 

 71 ; superphosphates, 81 et seq. 



Phosphoric acid : derivation, 61 ; 

 in animal matter, 62 ; guarantees 

 and grades, 65; in mineral 

 matter, 68 ; in basic slag, 72 ; in 

 manufactured phosphates, 73 ; 

 derived by plant from phosphates 

 through decay, 76; conditions 

 which affect availability, 76; 

 forms : insoluble, 81 ; soluble, 

 82, 84; reverted, 82; "free" 

 phosphoric acid, 91 ; soluble in 

 water, but fixed in soil, 92. 



Phosphorus powder, 117. 



Pigeon manure, 46, 125. 



Plant-food, available, unavailable, 

 23. 



Plaster, land, 144. 



Plums, 328. 



Potash : importance, 93 ; avail- 

 ability, 94. 



Forms: crude products, 96- 

 100 ; manufactured products, 96 ; 

 fixation in soil, 100. 



Sources of: kainit, 95; hard- 

 salt, 96; carnallit, 96; muriate, 

 96; high-grade sulfate, 97; 

 double manure salt, 98; potash 

 manure salt, 98; double car- 

 bonate of potash and magnesia, 

 98; carbonate, 99; nitrate, 99; 

 feldspar, 99 ; seaweeds, 100. 



Potatoes : fertilizer constituents in, 

 16 ; in crop rotation, 209 ; field 



