Contents
| PART I.—HISTORICAL INTRODUCTION. | |||
| PAGE | |||
| Beginning of agricultural chemistry | 4 | ||
| Early theories regarding plant-growth | 4 | ||
| Van Helmont | 4 | ||
| Digby | 6 | ||
| Duhamel and Stephen Hales | 8 | ||
| Jethro Tull | 9 | ||
| Charles Bonnet’s discovery of source of plants’ carbon | 11 | ||
| Researches of Priestley, Ingenhousz, Sénébier, on assimilation of carbon | 11-12 | ||
| Publication of first English treatise by Earl Dundonald | 13 | ||
| Publication of Theodore de Saussure, ‘Chemical Researches on Vegetation,’ 1804 | 14 | ||
| Theories on source of plant-nitrogen | 15 | ||
| Early experiments on this subject | 16 | ||
| Sir Humphry Davy’s lectures (1802-1812) | 17 | ||
| State of agricultural chemistry in 1812 | 17 | ||
| Beginning of Boussingault’s researches (1834) | 21 | ||
| Publication of Liebig’s first report to the British Association | 24 | ||
| Refutation of “humus” theory | 26 | ||
| Liebig’s mineral theory | 26 | ||
| Liebig’s theory of source of plants’ nitrogen | 27 | ||
| Publication of Liebig’s second report to British Association | 30 | ||
| Liebig’s services to agricultural chemistry | 31 | ||
| Development of agricultural research in Germany | 32 | ||
| The Rothamsted Experiment Station | 33 | ||
| Sir J. B. Lawes and Sir J. H. Gilbert, the nature and value of their experiments | 33 | ||
| Review of the present state of our knowledge of plant-growth | 36 | ||
| Proximate composition of the plant | 36 | ||
| Fixation of carbon by plants | 37 | ||
| Action of light on plant-growth, Dr Siemens’ experiments | 38 | ||
| Source of oxygen and hydrogen in the plant | 39-40 | ||
| Source of nitrogen in the plant | 40 | ||
| Relation of the free nitrogen to leguminous plants | 42-44 | ||
| Relation of nitrogen in organic forms, as ammonia salts, and nitrates to the plant | 46-50 | ||
| Nitrification and its conditions | 51 | ||
| Ash constituents of the plant | 53 | ||
| Methods of research for ascertaining essentialness of ash constituents of plants | 53 | ||
| (a) Artificial soils, (b) water-culture | 53-55 | ||
| Method in which plants absorb their food-constituents | 55 | ||
| Endosmosis | 55 | ||
| Retention by soils of plant-food | 57 | ||
| Causes of retention by soils of plant-food | 59 | ||
| Manuring | 60 | ||
| “Field” and “pot” experimentation | 60 | ||
| PART II.—PRINCIPLES OF MANURING. | |||
| CHAPTER I.—FERTILITY OF THE SOIL. | |||
| What constitutes fertility in a soil | 65 | ||
| I. | Physical properties of a soil | 65 | |
| Kinds of soils | 66 | ||
| Absorptive power for water of soils | 67 | ||
| Absorptive power for water of sand, clay, and humus | 68 | ||
| Fineness of particles of a soil | 69 | ||
| Limit of fineness of soil-particles | 69 | ||
| Importance of retentive power | 70 | ||
| Power of plants for absorbing water from a soil, experiments by Sachs | 73 | ||
| How to increase absorptive power of soils | 74 | ||
| Amount of water in a soil most favourable for plant growth | 75 | ||
| Hygroscopic power of soils | 75 | ||
| Capacity of soils for absorbing and retaining heat | 76 | ||
| Explanation of dew | 77 | ||
| Heat of soils | 78 | ||
| Heat in rotting farmyard manure | 78 | ||
| Causes of heat of fermentation | 79 | ||
| Influence of colour on heat-retaining power | 80 | ||
| Power of soils for absorbing gases | 81 | ||
| Gases found in soils | 81 | ||
| Variation in gas-absorbing power of soils | 82 | ||
| Absorption of nitrogen by soils | 82 | ||
| Requirements of plant-roots in a soil | 83 | ||
| Influence of tillage on number of plants in a certain area | 86 | ||
| Comparison of English and American farming | 86 | ||
| II. | Chemical composition of a soil | 87 | |
| Fertilising ingredients of a soil | 87 | ||
| Importance of nitrogen, phosphoric acid, and potash in a soil | 88 | ||
| Chemical condition of fertilising ingredients in soils | 89 | ||
| Amount of soluble fertilising ingredients in soils | 90 | ||
| Value of chemical analysis of soils | 90 | ||
| III. | Biological properties of a soil | 92 | |
| Bacteria of the soil | 92 | ||
| Recapitulation of Chapter I | 96 | ||
| APPENDIX TO CHAPTER I. | |||
| NOTE | |||
| I. | Table of absorptive power of soil substances by Schübler | 98 | |
| II. | Table of rate of evaporation of water in different soils by Schübler | 99 | |
| III. | Table of hygroscopic power of soils dried at 212° F. (Davy) | 99 | |
| IV. | Gases persent in soil | 100 | |
| V. | Amount of plant-food in soils | 100 | |
| VI. | Chemical composition of the soil | 101 | |
| VII. | Forms in which plant-foods are present in the soil | 107 | |
| CHAPTER II.—FUNCTIONS PERFORMED BY MANURES. | |||
| Etymological meaning of word manure | 109 | ||
| Definition of manures | 110 | ||
| Different classes of manures | 111 | ||
| Action of different classes of manures | 113 | ||
| CHAPTER III.—POSITION OF NITROGEN IN AGRICULTURE. | |||
| The Rothamsted experiments and the nitrogen question | 115 | ||
| Different forms in which nitrogen exists in nature | 116 | ||
| Relation of “free” nitrogen to the plant | 117 | ||
| Combined nitrogen in the air | 118 | ||
| Amount of combined nitrogen falling in the rain | 119 | ||
| Nitrogen in the soil | 120 | ||
| Nitrogen in the subsoil | 121 | ||
| Nitrogen of surface-soil | 121 | ||
| Amount of nitrogen in the soil | 123 | ||
| Soils richest in nitrogen | 123 | ||
| Nature of the nitrogen in the soil | 124 | ||
| Organic nitrogen in the soil | 125 | ||
| Differences of surface and subsoil nitrogen | 126 | ||
| Nitrogen as ammonia in soils | 127 | ||
| Amount of ammonia in soils | 127 | ||
| Nitrogen present as nitrates in the soil | 128 | ||
| Position of nitric nitrogen in soil | 128 | ||
| Amount of nitrates in the soil | 120 | ||
| Amount of nitrates in fallow soils | 129 | ||
| Amount of nitrates in cropped soils | 130 | ||
| Amount of nitrates in manured wheat-soils | 131 | ||
| The sources of soil-nitrogen | 131 | ||
| Accumulation of soil-nitrogen under natural conditions | 133 | ||
| Accumulation of nitrogen in pastures | 134 | ||
| Gain of nitrogen with leguminous crops | 135 | ||
| The fixation of “free” nitrogen | 136 | ||
| Influence of manures in increasing soil-nitrogen | 136 | ||
| Sources of loss of nitrogen | 137 | ||
| Loss of nitrates by drainage | 137 | ||
| Prevention of loss of nitrogen by permanent pasture and “catch-cropping” | 138 | ||
| Other conditions diminishing loss of nitrates | 139 | ||
| Amount of loss of nitrogen by drainage | 140 | ||
| Loss of nitrogen in form of “free” nitrogen | 141 | ||
| Total amount of loss of nitrogen | 142 | ||
| Loss of nitrogen by retrogression | 142 | ||
| Artificial sources of loss of nitrogen | 144 | ||
| Amount of nitrogen removed in crops | 144 | ||
| Losses of nitrogen incurred on the farm | 146 | ||
| Loss in treatment of farmyard manure | 146 | ||
| Nitrogen removed in milk | 147 | ||
| Economics of the nitrogen question | 147 | ||
| Loss of nitrogen-compounds in the arts | 148 | ||
| Loss due to use of gunpowder | 148 | ||
| Loss due to sewage disposal | 149 | ||
| Our artificial nitrogen supply | 150 | ||
| Nitrate of soda and sulphate of ammonia | 150 | ||
| Peruvian guano | 151 | ||
| Bones | 151 | ||
| Other nitrogenous manures | 152 | ||
| Oil-seeds and oilcakes | 153 | ||
| Other imported sources of nitrogen | 153 | ||
| Conclusion | 153 | ||
| APPENDIX TO CHAPTER III. | |||
| NOTE | |||
| I. | Determination of the quantity of nitrogen supplied by rain, as ammonia and nitric acid, to an acre of land during one year | 155 | |
| II. | Nitrogen in soils at various depths | 156 | |
| III | Nitrogen as nitrates in cropped soils receiving no nitrogenous manures, in lb. per acre (Rothamsted soils) | 157 | |
| IV. | Nitrogen as nitrates in Rothamsted soils | 157 | |
| V. | Examples of increase of nitrogen in Rothamsted soils laid down in pastures | 158 | |
| VI. | Loss by drainage of nitrates | 158 | |
| VII. | Examples of decrease of nitrogen in Rothamsted soils | 159 | |
| VIII. | Amount of drainage and nitrogen as nitrates in drainage-water from unmanured bare soil, 20 and 60 inches deep | 160 | |
| CHAPTER IV.—NITRIFICATION. | |||
| Process of nitrification | 161 | ||
| Occurrence of nitrates in the soil | 162 | ||
| Nitre soils of India | 162 | ||
| Saltpetre plantations | 163 | ||
| Cause of nitrification | 165 | ||
| Ferments effecting nitrification | 167 | ||
| Appearance of nitrous organisms | 168 | ||
| Nitric organism | 169 | ||
| Difficulty in isolating them | 169 | ||
| Nitrifying organisms do not require organic matter | 169 | ||
| Conditions favourable for nitrification— | |||
| Presence of food-constituents | 170 | ||
| Presence of a salifiable base | 171 | ||
| Only takes place in slightly alkaline solutions | 172 | ||
| Action of gypsum on nitrification | 173 | ||
| Presence of oxygen | 173 | ||
| Temperature | 175 | ||
| Presence of a sufficient quantity of moisture | 176 | ||
| Absence of strong sunlight | 176 | ||
| Nitrifying organisms destroyed by poisons | 176 | ||
| Denitrification | 177 | ||
| Denitrification also effected by bacteria | 178 | ||
| Conditions favourable for denitrification | 178 | ||
| Takes place in water-logged soils | 179 | ||
| Distribution of the nitrifying organisms in the soil | 179 | ||
| Depth down at which they occur | 180 | ||
| Action of plant-roots in promoting nitrification | 181 | ||
| Nature of substances capable of nitrification | 181 | ||
| Rate at which nitrification takes place | 183 | ||
| Nitrification takes place chiefly during summer | 183 | ||
| Process goes on most quickly in fallow fields | 184 | ||
| Laboratory experiments on rate of nitrification | 185 | ||
| Certain portions of soil-nitrogen more easily nitrifiable than the rest | 187 | ||
| Rate of nitrification deduced from field experiments | 187 | ||
| Quantity of nitrates formed in the soils of fallow fields | 188 | ||
| Position of nitrates depends on season | 188 | ||
| Nitrates in drainage-waters | 188 | ||
| Amount produced at different times of year | 189 | ||
| Nitrification of manures | 190 | ||
| Ammonia salts most easily nitrifiable | 191 | ||
| Sulphate of ammonia the most easily nitrifiable manure | 191 | ||
| Rate of nitrification of other manures | 192 | ||
| Soils best suited for nitrification | 192 | ||
| Absence of nitrification in forest-soils | 193 | ||
| Important bearing of nitrification on agricultural practice | 193 | ||
| Desirable to have soil covered with vegetation | 194 | ||
| Permanent pasture most economical condition of soil | 194 | ||
| Nitrification and rotation of crops | 195 | ||
| APPENDIX TO CHAPTER IV. | |||
| NOTE | |||
| I. | Old theories of nitrification | 196 | |
| II. | Nitrification takes place in solutions devoid of organic matter | 196 | |
| III. | Oxidising power of micro-organisms in soils | 197 | |
| IV. | Effect of urine on nitrification in soils | 197 | |
| V. | Solution used by Professor Frankland in cultivating nitrificative micro-organisms | 198 | |
| VI. | Experiments by Boussingault on rate of nitrification | 198 | |
| VII. | Nitrogen as nitrates in Rothamsted soils after bare fallow in lb. per acre | 198 | |
| CHAPTER V.—POSITION OF PHOSPHORIC ACID IN AGRICULTURE. | |||
| Occurrence of phosphoric acid in nature | 199 | ||
| Mineral sources of phosphoric acid | 200 | ||
| Apatite and phosphorite | 200 | ||
| Coprolites | 201 | ||
| Occurrence of phosphoric acid in guanos | 202 | ||
| Universal occurrence in common rocks | 202 | ||
| Occurrence in the soil | 203 | ||
| Condition in which phosphoric acid occurs in the soil | 203 | ||
| Occurrence in plants | 204 | ||
| Occurrence in animals | 205 | ||
| Sources of loss of phosphoric acid in agriculture | 205 | ||
| Loss of phosphoric acid by drainage | 206 | ||
| Artificial sources of loss of phosphoric acid | 206 | ||
| Amount of phosphoric acid removed in milk | 207 | ||
| Loss of phosphoric acid in treatment of farmyard manure | 208 | ||
| Loss of phosphoric acid in sewage | 208 | ||
| Sources of artificial gain of phosphoric acid | 208 | ||
| APPENDIX TO CHAPTER V. | |||
| NOTE | |||
| I. | Composition of apatite (Voelcker) | 210 | |
| II. | Percentage of phosphoric acid in the commoner rocks | 211 | |
| CHAPTER VI.—POSITION OF POTASH IN AGRICULTURE. | |||
| Potash of less importance than phosphoric acid | 212 | ||
| Occurrence of potash | 213 | ||
| Felspar and other potash minerals | 213 | ||
| Stassfurt salts | 214 | ||
| Occurrence of saltpetre | 215 | ||
| Occurrence of potash in the soil | 215 | ||
| Potash chiefly in insoluble condition in soils | 216 | ||
| Percentage of potash in plants and plant-ash | 216 | ||
| Occurrence of potash in animal tissue | 217 | ||
| Sources of loss of potash | 217 | ||
| Amount of potash removed in crops | 218 | ||
| Amount of potash removed in milk | 218 | ||
| Potash manures | 218 | ||
| APPENDIX TO CHAPTER VI. | |||
| NOTE | |||
| I. | Amount of potash in different minerals | 220 | |
| II. | Quantity of potash obtained from 1000 lb. of different kinds of vegetation in the manufacture of potashes | 220 | |
| PART III.—MANURES. | |||
| CHAPTER VII.—FARMYARD MANURE. | |||
| Variation in its composition | 223 | ||
| Made up of three classes of constituents | 224 | ||
| Solid excreta— | |||
| Its nature | 224 | ||
| Difference in composition of the solid excreta of the different farm animals | 224 | ||
| Causes of this difference | 225 | ||
| Percentage of manurial ingredients in solid excreta of different animals | 226 | ||
| Urine— | 228 | ||
| Its nature | 228 | ||
| Variation in its composition | 229 | ||
| Causes of this variation | 229 | ||
| Manurial value of the urine of the different farm animals | 230 | ||
| Percentage of the organic matter, nitrogen, and mineral substances in the food, voided in the solid excreta and urine | 232 | ||
| Comparison of manurial value of total excrements of the different farm animals | 234 | ||
| Nature of changes undergone by food in process of digestion | 235 | ||
| Litter— | 236 | ||
| Its uses | 236 | ||
| Straw as litter, and its qualifications | 237 | ||
| Composition of different kinds of straw | 238 | ||
| Loam as litter | 239 | ||
| Peat as litter | 240 | ||
| Comparison of properties of peat-moss and straw | 241 | ||
| The bracken-fern as litter | 241 | ||
| Dried leaves as litter | 242 | ||
| Manures produced by the different animals— | |||
| Horse-manure— | |||
| Amount produced | 243 | ||
| Its nature and composition | 243 | ||
| Amount of straw used for litter | 244 | ||
| Sources of loss on keeping | 245 | ||
| How to prevent loss | 245 | ||
| Use of “fixers,” and the nature of their action | 245 | ||
| Cow-manure— | |||
| Amount produced | 248 | ||
| Its nature and composition | 249 | ||
| Amount of straw used as litter | 248 | ||
| Sources of loss on keeping | 249 | ||
| Advantages of short dung | 249 | ||
| Pig-manure— | |||
| Amount produced | 250 | ||
| Its nature and composition | 250 | ||
| Amount of straw used as litter | 251 | ||
| Sheep-manure— | |||
| Amount produced | 251 | ||
| Nature and composition | 251 | ||
| Amount of straw used as litter | 252 | ||
| Methods of calculating amount of manure produced on the farm | 252, note | ||
| Fermentation of farmyard manure— | |||
| Action of micro-organic life in producing fermentation | 255 | ||
| Two classes of bacteria active in this work, aerobies and anaerobies | 255 | ||
| Conditions influencing fermentation— | |||
| Temperature | 256 | ||
| Openness to the air | 256 | ||
| Dampness | 257 | ||
| Composition of manure | 257 | ||
| Products of fermentation | 257 | ||
| Analyses of farmyard manure— | |||
| Dr Voelcker’s experiments | 259 | ||
| Variation in composition | 259 | ||
| Amounts of moisture, organic matter (containing nitrogen), and mineral matter | 260 | ||
| Its manurial value compared with nitrate of soda, sulphate of ammonia, and superphosphate | 260 | ||
| Comparison of fresh and rotten manure— | |||
| The nature and amount of loss sustained in the process of rotting | 261 | ||
| Ought manure to be appliled fresh or rotten? | 262 | ||
| Relative merits of covered and uncovered manure-heaps | 263 | ||
| Methods of application of farmyard manure to the field— | |||
| Merits and demerits of the different methods | 265 | ||
| Setting it out in heaps | 265 | ||
| Spreading it broadcast, and letting it lie | 266 | ||
| Ploughing it in immediately | 267 | ||
| Value and function of farmyard manure— | |||
| As a supplier of the necessary elements of plant-food | 268 | ||
| As a “universal” manure | 269 | ||
| Proportion in which nitrogen, phosphoric acid, and potash are required by crops | 269 | ||
| Proportion in which they are present in farmyard manure | 270 | ||
| Farmyard manure poor in nitrogen | 270 | ||
| Lawes’ and Gilbert’s experiments | 271 | ||
| How it may be best reinforced by the use of “artificials” | 271 | ||
| Indirect value of farmyard manure as a supplier of humus to the soil | 273 | ||
| Its influence on soil-texture | 273 | ||
| Its influence in setting free inert fertilising matter in the soil | 274 | ||
| Rate at which farmyard manure ought to be applied | 275 | ||
| Lasting nature of farmyard manure | 276 | ||
| Its economic value | 276 | ||
| APPENDIX TO CHAPTER VII. | |||
| NOTE | |||
| I. | Difference in amount of excreta voided for food consumed | 279 | |
| II. | Solid excreta voided by sheep, oxen, and cows | 279 | |
| III. | Urine voided by sheep, oxen, and cows | 280 | |
| IV. | Percentage of food voided in the solid and liquid excrements | 281 | |
| V. | Pig excrements | 281 | |
| VI. | Manurial constituents in 1000 parts of ordinary foods | 282 | |
| VII. | Analyses of stable-manure, made respectively with peat-moss litter and wheat-straw | 283 | |
| VIII. | Analyses of bracken | 283 | |
| IX. | Analyses of horse-manure | 283 | |
| X. | The nature of the chemical reactions of ammonia “fixers” | 284 | |
| XI. | Analyses of cow-manure | 286 | |
| XII. | Composition of fresh and rotten farmyard manure | 286 | |
| XIII. | Comparison of fresh and rotten manure | 288 | |
| XIV. | Lord Kinnaird’s experiments | 289 | |
| XV. | Drainings of manure-heaps | 290 | |
| XVI. | Amounts of potash and phosphoric acid removed by rotation from a Prussian morgen (.631 acre) | 290 | |
| XVII. | Composition of farmyard manure (fresh) | 291 | |
| XVIII. | The urine (quantity voided) | 291 | |
| CHAPTER VIII.—GUANO. | |||
| Importance in agriculture | 293 | ||
| Influence on British farming | 294 | ||
| Influence of guano not wholly good | 295 | ||
| Value of guano as a manure | 296 | ||
| Origin and occurrence of guano | 297 | ||
| Variation in composition of different guanos | 299 | ||
| I. | Nitrogenous guano— | ||
| (a) | Peruvian guano | 300 | |
| Different deposits of Peruvian guano | 301 | ||
| Appearance, colour, and nature of Peruvian guano | 303 | ||
| Composition of Peruvian guano | 304 | ||
| (b) | Other nitrogenous manures: Angamos, Ichaboe | 306 | |
| II. | Phosphatic guanos— | ||
| Occurrence of phosphatic guanos | 308 | ||
| Inequality in composition of phosphatic guanos | 309 | ||
| “Dissolved” phosphatic guano | 310 | ||
| “Equalised” or “rectified” guano | 311 | ||
| The action of phosphatic guanos as manures | 312 | ||
| Proportion of fertilising constituents in guano | 314 | ||
| Mode of application of guanos | 315 | ||
| Quantity of guano to be used | 317 | ||
| Adulteration of guano | 318 | ||
| So-called guanos— | |||
| Fish-guano | 320 | ||
| Value of fish-guano | 322 | ||
| Mean-meal guano | 324 | ||
| Value of meat-meal guano | 324 | ||
| Bat guano | 325 | ||
| Pigeon and fowl dung | 325 | ||
| APPENDIX TO CHAPTER VIII. | |||
| NOTE | |||
| I. | Peruvian guano imported into United Kingdom, 1865-1893 | 327 | |
| II. | Guano deposits of the world | 327 | |
| III. | Composition of concretionary nodules | 328 | |
| IV. | Table showing gradual deterioration of Peruvian guano, 1867-1881 | 329 | |
| V. | Composition of different guanos | 329 | |
| VI. | Liebig’s theory as to the action of oxalic acid in guano | 330 | |
| VII. | Analyses of dung of fowls, pigeons, ducks, and geese | 331 | |
| CHAPTER IX.—NITRATE OF SODA. | |||
| Amount of exports | 332 | ||
| Date of discovery of nitrate deposits | 333 | ||
| The origin of nitrate deposits | 334 | ||
| Forbes and Darwin on the theory of their origin | 335 | ||
| Source of nitric acid in nitrate of soda | 337 | ||
| Guano theory of origin of nitrate of soda | 337 | ||
| Nitric acid in nitrate of soda probably derived from sea-weed | 339 | ||
| Appearance of nitrate-fields | 340 | ||
| The method of mining the nitrate of soda | 341 | ||
| Composition of caliche | 342 | ||
| Extent of the nitrate deposits | 342 | ||
| Composition and properties of nitrate of soda | 343 | ||
| Nitrate applied as a top-dressing | 344 | ||
| Nitrate of soda encourages deep roots | 344 | ||
| Is nitrate of soda an exhausting manure? | 345 | ||
| Crops for which nitrate of soda is suited | 346 | ||
| Method of application of nitrate of soda | 347 | ||
| Importance of having a sufficiency of other fertilising constituents | 348 | ||
| Conclusions drawn | 349 | ||
| APPENDIX TO CHAPTER IX. | |||
| Total shipmentes from South America, 1830-1893 | 351 | ||
| Total imports into Europe and United Kingdom, 1873-1892 | 351 | ||
| CHAPTER X.—SULPHATE OF AMMONIA. | |||
| Value of ammonia as a manure | 352 | ||
| Sources of sulphate of ammonia | 353 | ||
| Ammonia from gas-works | 353 | ||
| Other sources | 354 | ||
| Composition, &c., of sulphate of ammonia | 355 | ||
| Application of sulphate of ammonia | 356 | ||
| APPENDIX TO CHAPTER X. | |||
| Production of sulphate of ammonia in United Kingdom, 1870-1892 | 358 | ||
| CHAPTER XI.—BONES. | |||
| Early use of bones | 359 | ||
| Different forms in which bones are used | 360 | ||
| Composition of bones | 362 | ||
| The organic matter of bones | 363 | ||
| The inorganic matter of bones | 363 | ||
| Treatment of bones | 364 | ||
| Action of bones | 365 | ||
| Dissolved bones | 368 | ||
| Crops suited for bones | 368 | ||
| Bone-ash | 369 | ||
| Bone-char or bone-black | 369 | ||
| APPENDIX TO CHAPTER XI. | |||
| NOTE | |||
| I. | Analysis of bone-meal | 371 | |
| II. | Analysis of dissolved bones | 371 | |
| III. | Composition of bone-ash | 372 | |
| IV. | Composition of bone-char | 372 | |
| CHAPTER XII.—MINERAL PHOSPHATES. | |||
| Coprolites | 373 | ||
| Canadian apatite or phosphorite | 374 | ||
| Estremadura or Spanish phosphates | 375 | ||
| Norwegian apatite | 376 | ||
| Charlestown or South Carolina phosphate | 376 | ||
| Belgian phosphate | 377 | ||
| Somme phosphate | 378 | ||
| Florida phosphate | 378 | ||
| Lahn phosphate | 379 | ||
| Bordeaux or French phosphate | 379 | ||
| Algerian phosphate | 379 | ||
| Crust guanos | 379 | ||
| Value of mineral phosphates as manures | 380 | ||
| APPENDIX TO CHAPTER XII. | |||
| Imports of phosphates | 381 | ||
| CHAPTER XIII.—SUPERPHOSPHATES. | |||
| Discovery of superphosphate by Liebig | 382 | ||
| Manufacture of superphosphate | 383 | ||
| Nature of the reaction taking place | 385 | ||
| Phosphates of lime | 385 | ||
| Reverted phosphate | 389 | ||
| Value of reverted phosphate | 391 | ||
| Composition of superphosphates | 391 | ||
| Action of superphosphates | 392 | ||
| Action of superphosphate sometimes unfavourable | 395 | ||
| Application of superphosphate | 395 | ||
| Value of insoluble phosphates | 396 | ||
| Rate at which superphosphate is applied | 397 | ||
| APPENDIX TO CHAPTER XIII. | |||
| NOTE | |||
| I. | The formulæ, and molecular and percentage composition, of the different phosphates | 398 | |
| II. | Reactions of sulphuric acid and phosphate of lime | 398 | |
| III. | Table for conversion of soluble phosphate into insoluble phosphate | 399 | |
| IV. | Action of iron and alumina in causing reversion | 399 | |
| V. | Relative trade values of phosphoric acid in different manures | 400 | |
| CHAPTER XIV.—PHOSPHATE OR BASIC SLAG. | |||
| Its manufacture | 401 | ||
| Not at first used | 403 | ||
| Discovery of its value as a manure | 403 | ||
| Composition of basic slag | 404 | ||
| Processes for preparing slag | 406 | ||
| Solubility of basic slag | 408 | ||
| Darmstadt experiments with basic slag | 410 | ||
| Results of other experiments | 413 | ||
| Soils most suited for slag | 414 | ||
| Rate of application | 414 | ||
| Method of application | 416 | ||
| APPENDIX TO CHAPTER XIV. | |||
| Analysis of basic slag | 417 | ||
| CHAPTER XV.—POTASSIC MANURES. | |||
| Relative importance | 418 | ||
| Scottish soils supplied with potash | 419 | ||
| Sources of potassic manures | 419 | ||
| Stassfurt potash salts | 420 | ||
| Relative merits of sulphate and muriate of potash | 421 | ||
| Application of potash manures | 422 | ||
| Soils and crops suited for potash manures | 423 | ||
| Rate of application | 423 | ||
| CHAPTER XVI.—MINOR ARTIFICIAL MANURES. | |||
| Scutch | 427 | ||
| Shoddy and wool-waste | 427 | ||
| Soot | 428 | ||
| CHAPTER XVII.—SEWAGE AS A MANURE. | |||
| Irrigation | 431 | ||
| Effects of continued application of sewage | 433 | ||
| Intermittent irrigation | 434 | ||
| Crops suited for sewage | 434 | ||
| Treatment of sewage by precipitation, &c. | 436 | ||
| Value of sewage sludge | 439 | ||
| CHAPTER XVIII.—LIQUID MANURE | 442 | ||
| CHAPTER XIX.—COMPOSTS. | |||
| Farmyard manure a typical compost | 446 | ||
| Other composts | 447 | ||
| CHAPTER XX.—INDIRECT MANURES. | |||
| Lime | 449 | ||
| Antiquity of lime as a manure | 449 | ||
| Action of lime | 449 | ||
| Lime a necessary plant-food | 450 | ||
| Lime of abundant occurrence | 452 | ||
| Lime returned to the soil in ordinary agricultural practice | 452 | ||
| Different forms of lime | 453 | ||
| Caustic lime | 453 | ||
| Lime acts both mechanically and chemically | 455 | ||
| I. | Mechanical functions of lime | 455 | |
| Action on soil’s texture | 455 | ||
| Lime renders light soils more cohesive | 457 | ||
| II. | Chemical action of lime | 457 | |
| III. | Biological action of lime | 459 | |
| Action of lime on nitrogenous organic matter | 460 | ||
| Recapitulation | 461 | ||
| CHAPTER XXI.—INDIRECT MANURES—GYPSUM, SALT, Etc. | |||
| Gypsum | 462 | ||
| Mode in which gypsum acts | 462 | ||
| Salt | 465 | ||
| Antiquity of the use of salt | 465 | ||
| Nature of its action | 465 | ||
| Salt not a necessary plant-food | 466 | ||
| Can soda replace potash? | 466 | ||
| Salt of universal occurrence | 467 | ||
| Special sources of salt | 468 | ||
| The action of salt | 468 | ||
| Mechanical action on soils | 470 | ||
| Solvent action | 470 | ||
| Best used in small quantities along with manures | 472 | ||
| Affects quality of crop | 472 | ||
| Rate of application | 473 | ||
| CHAPTER XXII.—THE APPLICATION OF MANURES. | |||
| Influence of manures in increasing soil-fertility | 474 | ||
| Influence of farmyard manure on the soil | 475 | ||
| Farmyard manure v. artificials | 476 | ||
| Farmyard manure not favourable to certain crops | 477 | ||
| Conditions determining the application of artificial manures | 477 | ||
| Nature of the manure | 478 | ||
| Nitrogenous manures | 478 | ||
| Phosphatic manures | 480 | ||
| Potash manures | 480 | ||
| Nature of soil | 481 | ||
| Nature of previous manuring | 482 | ||
| Nature of the crop | 483 | ||
| Amounts of fertilising ingredients removed from the soil by different crops | 484 | ||
| Capacity of crops for assimilating manures | 486 | ||
| Difference in root-systems of different crops | 488 | ||
| Period of growth | 489 | ||
| Variation in composition of crops | 490 | ||
| Absorption of plant-food | 490 | ||
| Fertilising ingredients lodge in the seed | 491 | ||
| Forms in which nitrogen exists in plants | 491 | ||
| Bearing of above on agricultural practice | 492 | ||
| Influence of excessive manuring of crops | 492 | ||
| CHAPTER XXIII.—MANURING OF THE COMMON FARM CROPS. | |||
| Cereals | 493 | ||
| Especially benefited by nitrogenous manures | 494 | ||
| Power of absorbing silicates | 494 | ||
| Barley | 495 | ||
| Period of growth | 495 | ||
| Most suitable soil | 496 | ||
| Farmyard manure not suitable | 497 | ||
| Importance of uniform manuring of barley | 497 | ||
| Norfolk experiments on barley | 497 | ||
| Proportion of grain to straw | 498 | ||
| Wheat | 499 | ||
| Rothamsted experiments | 500 | ||
| Continuous growth | 500 | ||
| Flitcham experiments | 500 | ||
| Oats | 501 | ||
| A very hardy crop | 502 | ||
| Require mixed nitrogenous manuring | 502 | ||
| Arendt’s experiments | 503 | ||
| Avenine | 503 | ||
| Quantities of manures | 504 | ||
| Grass | 504 | ||
| Effect of manures on herbage of pastures | 505 | ||
| Influence of farmyard manure | 506 | ||
| Influence of soil and season on pastures | 507 | ||
| Manuring of meadow land | 508 | ||
| Bangor experiments | 508 | ||
| Norfolk experiments | 509 | ||
| Manuring of permanent pastures | 509 | ||
| Roots | 510 | ||
| Influence of manure on composition | 512 | ||
| Nitrogenous manures increase sugar | 512 | ||
| Amount of nitrogen recovered in increase of crop | 513 | ||
| Norfolk experiments | 513 | ||
| Manure for swedes | 514 | ||
| Highland Society’s experiments | 515 | ||
| Manuring for rich crops of turnips | 516 | ||
| Experiments by the author on turnips | 516 | ||
| Potatoes | 517 | ||
| Highland Society’s experiments | 518 | ||
| The Rothamsted experiments | 519 | ||
| Effect of farmyard manure | 520 | ||
| Manuring of potatoes in Jersey | 521 | ||
| The influence of manure on the composition | 521 | ||
| Leguminous crops | 522 | ||
| Leguminous plants benefit by potash | 523 | ||
| Nitrogenous manures may be hurtful | 523 | ||
| Clover sickness | 524 | ||
| Alternate wheat and bean rotation | 524 | ||
| Beans | 525 | ||
| Manure for beans | 525 | ||
| Relative value of manurial ingredients | 526 | ||
| Gypsum as a bean manure | 526 | ||
| Effect of manure on composition of crop | 527 | ||
| Peas | 527 | ||
| Hops | 528 | ||
| Cabbages | 528 | ||
| APPENDIX TO CHAPTER XXIII. | |||
| Experiments on bean-manuring | 530 | ||
| CHAPTER XXIV.—ON THE METHOD OF APPLICATION, AND ON THE MIXING OF MANURES | |||
| Equal distribution of manures | 531 | ||
| Mixing manures | 532 | ||
| Risks of loss in mixtures | 533 | ||
| Loss of ammonia | 533 | ||
| Effects of lime on ammonia | 535 | ||
| Loss of nitric acid | 536 | ||
| Reversion of phosphates | 537 | ||
| Manurial ingredients should be applied separately | 538 | ||
| CHAPTER XXV.—ON THE VALUATION AND ANALYSIS OF MANURES. | |||
| Value of chemical analysis | 539 | ||
| Interpretation of chemical analysis | 539 | ||
| Nitrogen | 540 | ||
| Phosphoric acid | 541 | ||
| Importance of mechanical condition of phosphate | 542 | ||
| Potash | 542 | ||
| Other items in the chemical analysis of manures | 543 | ||
| Fertilisers and Feeding Stuffs Act | 543 | ||
| Different methods of valuing manures | 544 | ||
| Unit value of manurial ingredients | 544 | ||
| Intrinsic value of manures | 545 | ||
| Field experiments | 545 | ||
| Educational value of field experiments | 547 | ||
| Value of manures deduced from experiments | 548 | ||
| Value of unexhausted manures | 549 | ||
| Potential fertility of a soil | 549 | ||
| Tables of value of unexhausted manures | 551 | ||
| APPENDIX TO CHAPTER XXV. | |||
| NOTE | |||
| I. | Factors for calculating compounds from manurial ingredients | 553 | |
| II. | Units for determining commercial value of manures and cash prices of manures | 554, 555 | |
| III. | Manurial value of nitrogen and potash in different substances | 556 | |
| IV. | Comparative manurial value of different forms of nitrogen and potash | 557 | |
| V. | Lawes’ and Gilbert’s tables for calculating unexhausted value of manures | 559 | |
| CHAPTER XXVI.—THE ROTHAMSTED EXPERIMENTS. | |||
| Nature of experiments on crops and manures | 561 | ||
| Soil of Rothamsted | 561 | ||
| Table I. List of Rothamsted field experiments | 562 | ||
| Wheat experiments— | |||
| Unmanured plots | 565 | ||
| Wheat grown continuously on same land (unmanured) | 562 | ||
| Table II. Results of first eight years | 562 | ||
| Table III. Results of subsequent forty years | 562 | ||
| Tablel IV. Wheat grown continuously with farmyard manure (14 tons per annum) | 564 | ||
| Table V. Wheat grown continuously with artificial manures | 565 | ||
| Table VI. Experiments on the growth of barley, forty years, 1852-91 | 566 | ||
| Table VIII. Experiments on the growth of oats, 1869-78 | 567 | ||
| Table IX. Experiments on mangel-wurzel | 568, 569 | ||
| Table X. Experiments with different manures on permanent meadow-land, thirty-six years, 1856-91 | 570 | ||
| Table XI. Experiments on the growth of potatoes— average for five seasons, 1876-80 | 571 | ||
| Table XII. Experiments on growth of potatoes (continued)—average for twelve seasons, 1881-92 | 572 | ||
| _______________ | |||
| Index | 573 | ||