Principles and practice of agricultural analysis. Volume 2 (of 3), Fertilizers — Reading Companion

Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Equal signs “=” before and after a word or phrase indicate =bold= in the original text. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Old spellings have been preserved, e.g. "dioxid" instead of "dioxide". Typographical and punctuation errors have been silently corrected.

PRINCIPLES AND PRACTICE OF AGRICULTURAL ANALYSIS.

A MANUAL FOR THE ESTIMATION OF SOILS, FERTILIZERS, AND AGRICULTURAL PRODUCTS.

FOR THE USE OF ANALYSTS, TEACHERS, AND STUDENTS OF AGRICULTURAL CHEMISTRY.

BY HARVEY W. WILEY, CHEMIST OF THE U. S. DEPARTMENT OF AGRICULTURE.

EASTON, PA., CHEMICAL PUBLISHING CO., 1895.

COPYRIGHT, 1895, BY HARVEY W. WILEY.

PREFACE TO VOLUME SECOND.

In this volume an attempt has been made to treat the subject of fertilizers and fertilizing materials in the manner followed in the first volume with soils. The general principles of fertilizer manufacture and application have been presented in so far as they seemed to throw light on the rational method of examination and analysis. The standard methods of analysis in use in this and other countries, have been presented with sufficient fullness for the guidance of the skilled worker, and the information of the student. To those who make use of a book only for routine work or for preparation for an examination, this volume, as its predecessor, will be found to have little attraction. This fact, however, will not be a cause of regret to the author whose purpose has been, avowedly, to present to the busy worker and student a broad view of a great subject which each one does not have the time to search out for himself.

It is a matter of regret, however, that the contents of the volume have again exceeded all expectations. It was found impracticable to secure any greater condensation without departing from the purpose, and impairing the completeness of the work. When work is done with no prospect of financial compensation, it is gratifying to find it appreciated, and the author will be content to have this volume meet with as kindly a reception as has been accorded volume one.

HARVEY W. WILEY. WASHINGTON, D. C., End of July, 1895.

TABLE OF CONTENTS OF VOLUME SECOND.

PART FIRST. PHOSPHATES AND PHOSPHATIC FERTILIZERS.

_Introduction_, pp. 1-4.—Natural fertilizers; Waste matters as fertilizing materials; Valuation of fertilizing ingredients.

_General Analytical Processes_, pp. 4-15.—Taking samples; Fertilizing minerals; Mixed fertilizers; French methods of taking samples; Sampling stable manures; Preparation of sample in laboratory; French and German methods; Drying fertilizer samples; Moisture in acid phosphates.

_Analysis of Mineral Phosphates_, pp. 15-39.—Constituents to be determined; Direct estimation of phosphoric acid; Official method; Preparation of solution; Use of tartaric acid; Determination of water and organic matters; Carbon dioxid; Soluble and insoluble matter; Silica and insoluble bodies; Estimation of lime; Ammonium oxalate method; Immendorff method; Estimation of iron and alumina; The acetate and Hess methods; Methods of Jones and Crispo; Geological Survey method; Method of Marioni and Fasselli; Method of Krug and McElroy; Method of Wyatt; Estimation of magnesia; of sulfuric acid; of fluorin.

_General Methods for Phosphoric Acid_, pp. 39-57.—Preliminary considerations; Estimation as stannic phosphate; Water soluble acid; Citrate insoluble acid; Total phosphoric acid; Norwegian methods; German experiment station methods; Soluble phosphoric acid; Swedish methods; Dutch methods; Errors in molybdate method; Color of pyrophosphate; Solution in sulfuric acid.

_The Citrate Method_, pp. 57-70.—General principles; Halle method; Swedish method; Methods adopted at the Brussels Congress; Dutch method for citrate soluble acid; Comparative accuracy of citrate and molybdate methods.

_Basic Phosphatic Slags_, pp. 70-86.—History and manufacture; Composition; Molecular structure; Solubility; Separation and solution; Estimation of total acid; Alternate method; Halle method of analysis; Dutch method; Estimation of citrate soluble acid in basic slags; Wagner’s shaking and digesting apparatus; Estimation of caustic lime in slags; Detection of adulteration.

_Volumetric Determination of Phosphoric Acid_, pp. 86-106.—Classification of methods; Uranium method; Preparation of sample; Precipitation of the phosphoric acid by magnesium citrate; Composition of magnesium citrate solution; Solution of ammonium magnesium phosphate; Preparation of standard solutions; Verifying standard solutions; Conduct of the analysis; Phosphoric acid in superphosphates; Determination of soluble and reverted phosphoric acid; Conclusions.

_Titration of the Yellow Precipitate_, pp. 106-118.—Pemberton’s method; Conduct of the analysis; Reactions; Calculation of results; Comparison with Official method; Titration as a lead compound; Water soluble acid; Estimation of phosphoric acid in presence of a large excess of iron; Emmerton method; Method of Dudley and Noyes; The Jones reductor; The volumetric silver method.

_Technical Determination of Phosphoric Acid_, pp. 118-125.—Desirability of methods; Reagents employed; Conduct of the molybdenum method; Conduct of the citrate method; Treatment of mineral phosphates and basic slags; Analysis of superphosphates.

_Miscellaneous Notes on Phosphates and Phosphatic Fertilizers_, pp. 126-150.—Time required for precipitation; Examination of the pyrophosphate; Iodin in phosphates; Chromium in phosphates; Estimation of Vanadium; Fluorin in bones; Note on separation of iron and alumina from phosphoric acid; Ammonium citrate soluble acid; Influence of time and strength of solvent on solution; Arbitrary Determination of reverted phosphoric acid; Digestion apparatus of Huston; Huston’s mechanical stirrer; Citrate method with small percentage of phosphoric acid; Direct precipitation of the citrate soluble phosphoric acid; Availability of phosphatic fertilizers; Direct weighing of the molybdenum precipitate.

_Chemistry of the Manufacture of Superphosphates_, pp. 150-156.—Reactions with phosphates; with fluorids; with carbonates; with iron and alumina; with magnesium compounds; Determination of quantity of sulfuric acid; Phosphoric acid superphosphates; Authorities cited in Part First.

PART SECOND. NITROGEN IN FERTILIZERS AND FERTILIZING MATERIALS.

_Kinds of Nitrogen in Fertilizers_, pp. 161-169.—Determination of state of combination; Microscopic examination; Seeds and seed residues; Fish scrap; Dried blood and tankage; Horn, hoof, and hair; Ammoniacal nitrogen; Nitrogen in guanos; Nitric nitrogen.

_Methods of Analysis_, pp. 169-192.—Classification of methods; Official methods; Combustion in copper oxid; Official volumetric method; Mercury pump; Combustion furnace; Process of combustion; Method of Johnson and Jenkins; Calculating results; Reading barometer; Tension of aqueous vapor; Aqueous tension in solutions of potassium hydroxid; Tables for calculating results; Soda-lime process; Official French method; The ruffle soda-lime method; Official ruffle method; Boyer’s ruffle method.

_Moist Combustion Process_, pp. 192-220.—Historical; Method of Kjeldahl; Theory of the reactions; Preparation of reagents; Dutch kjeldahl method; Halle kjeldahl method; Official kjeldahl method; Distillation apparatus; Patrick’s distilling flask; Modification of the kjeldahl process; Method of Wilfarth; Method of Asboth; Method of Jodlbaur; Dutch jodlbaur method; Halle jodlbaur method; Official method for nitric nitrogen; Method of Scovell; Gunning method; Reactions of the gunning method; Official gunning method; Gunning method adapted to nitrates.

_Determination of Nitrogen in Definite Forms of Combination_, pp. 221-231.—Introductory considerations; Nitrogen as ammonia; Method of Boussingault; Determination of thiocyanates; Separation of albuminoid nitrogen; Separation of nitric nitrogen; Separation of ammoniacal nitrogen; Ulsch method for mixed fertilizers; Method of Schlöesing-Wagner; Schmitt’s modified method; Krüger’s method.

_Sodium Nitrate_, pp. 231-247.—Functions of sodium nitrate; Commercial forms of Chile saltpeter; Percentage of nitrogen in Chile saltpeter; Adulteration of Chile saltpeter; The Halle zinc-iron method for estimating nitrogen in Chile saltpeter; French method; Gantter’s volumetric method; Method of difference; Application of Chile saltpeter to the soil; Taking samples of soil to determine nitric nitrogen; The nitrifiable solution; Quantity of Chile saltpeter per acre; Consumption of Chile saltpeter; Authorities cited in Part Second.

_Potash in Fertilizing Materials and Fertilizers_, pp. 248-266.—Introduction; Forms of potash; Organic sources of potash; Tobacco stems and waste; Cottonseed hulls and meal; Wood ashes; Fertilizing value of ashes; Sugar beet molasses; Residue of wineries; Destruction of organic matter; Ignition with sulfuric acid; Potash in mineral deposits; Occurrence and history; Changes in potash salts _in situ_; Kainit; Carnallit; Polyhalit; Krugit; Sylvin; Sylvinit; Kieserit; Schönit; Potassium sulfate; Potassium magnesium carbonate; Potash in factory residues; Quantity of potash salts used.

_Methods of Analysis_, pp. 266-289.—Classification of methods; Platinic chlorid method; Official method; Alternate official method; Solution of organic compounds; Factors for calculation; Halle potash method; Dutch method; Swedish method; Method of the German Kali syndicate; Method for high grade potash salts; Barium oxalate method; de Roode method for kainit; Calcium chlorid method; Rapid control method; Determination from metallic platinum; Errors in platinum method;Effect of concentration on accuracy; Differences in form of crystals of potassium platinochlorid; Recovery of the platinum waste.

_Estimation of Potash as Perchlorate_, pp. 289-301.—General principles; Caspari’s method of preparing perchloric acid; Kreider’s method; Keeping properties of perchloric acid; The analytical process for determining potassium as perchlorate; Removal of sulfuric acid; Applicability of the process; Accuracy of the process; Authorities cited in Part Third.

_Miscellaneous Fertilizers_, pp. 302-324.—Classification; Forms of lime; Application of lime; Action of lime; Analysis of lime; Gypsum, or land plaster; Analysis of gypsum; Common salt; Green vitriol; Stall manures; Hen manure; Guanos and cave deposits; Official French method for phosphoric acid in guanos; Leather waste; Wood ashes; Analysis of wood ashes; Method of analysis used in this laboratory; Official method for estimating alkalies in wood ashes; Statement of results; Authorities cited in Part Fourth; Index.

ILLUSTRATIONS TO VOLUME SECOND.

Page. Figure 1. Apparatus for crushing mineral fertilizers 5 “ 2. Plate grinder for minerals 6 “ 3. Shaking apparatus for superphosphates 60 “ 4. Shaking machine for ammonium magnesium phosphate 64 “ 5. Rössler ignition furnace 65 “ 6. Wagner’s digestion apparatus for slags 79 “ 7. Jones’ reduction tube 115 “ 8. Huston’s digesting apparatus 142 “ 9. Huston’s mechanical stirrer 145 “ 10. Mercury pump and azotometer 174 “ 11. Moist combustion apparatus of the Halle agricultural laboratory 201 “ 12. Distillation apparatus of Halle agricultural laboratory 203 “ 13. Distilling apparatus 208 “ 14. Schlöesing-Wagner apparatus 229 “ 15. Halle nitric acid apparatus 234 “ 16. Gantter’s nitrogen apparatus 237 “ 17. Geological relations of the potash deposits near Stassfurt 258

EXAMINATION OF FERTILIZING MATERIALS, FERTILIZERS, AND MANURES.

PRELIMINARY TREATMENT AND PHOSPHATES.

=1. Introduction.=—In the first volume the principal plant foods occurring in soils have been named and the methods of estimating them described. As fertilizers are classed those materials which are added to soils to supply supposed deficiencies in plant foods, or to render more available the stores already present. There is little difference between the terms fertilizer and manure. In common language the former is applied to goods prepared for the farmer by the manufacturer or mixer, while the latter is applied to the stores accumulated about the stables or made elsewhere on the farm. Thus it is common to speak of a barnyard or stall manure and of a commercial fertilizer.

One of the objects of the analysis of soils, as described in the first volume of this work, is to determine the character of the fertilizer which should be added to a field in order to secure its maximum fertility.

One purpose of the present part is to determine the fitness of offered fertilizing material to supply the deficiencies which may be revealed by a proper study of the needs of the soil.

=2. Natural Fertilizers.=—In the succession of geologic epochs which has marked the natural history of the earth there have been brought together in deposits of greater or less magnitude the stores of plant food unused by growing crops or which may once have been part of vegetable and animal organisms. Some of these deposits have been mentioned in the first volume, paragraphs =11, 12=, and =18=.

For a full description of the extent and origin of these deposits the reader is referred to works on economic geology. These deposits are the chief sources of the commercial fertilizers which are offered to the farmers of to-day and to which the agricultural analyst is called upon to devote much of his time and labor. The methods of determining the chemical composition and agricultural value of these deposits, as practiced by the leading chemists of this country and Europe, will be fully set forth in the following pages.

=3. Waste Matters as Fertilizing Materials.=—In addition to the natural products just mentioned the analyst will be called on also to deal with a great variety of waste materials which, in the last few years, have been saved from the débris of factories and abattoirs, and prepared for use on the farm. Among these waste matters may be mentioned, bones, horns, hoofs, hair, tankage, dried blood, fish scrap, oil cakes, ashes, sewage, and sewage precipitates, offal of all kinds, leather scraps, and organic débris in general.

It is important, before beginning an analysis, to know the origin of the substances to be determined. As has already been pointed out in volume first the process which would be accurate with a substance of a mineral origin might lead to error if applied to the same element in organic combination. This is particularly true of phosphorus and potash. A simple microscopic examination will usually enable the analyst to determine the nature of the sample. In this manner, in the case of a phosphate, it would at once be determined whether it was bone, mineral, or basic slag. The odor, color, and general consistence will also aid in the determination.

=4. Valuation of Fertilizing Ingredients.=—Perhaps there are no more numerous and perplexing questions propounded to the analyst than those which relate to the value of fertilizing materials. There is none harder to answer. As a rule these questions are asked by the farmer, and refer to the fertilizers put down on his fields. In such cases the cost of transportation is an important factor in the answer. The farther the farmer is removed from the place of fertilizer manufacture the greater, as a rule, will be the cost. Whether the transportation is over land or by water also plays an important part in the final cost. The discovery of new stores of fertilizing materials has also much to do with the price. This fact is especially noticeable in this country, where the price of crude phosphates at the mines has fallen in a few years from nearly six dollars to three dollars and forty-three cents per ton[1]. This decrease has been largely due to discoveries of vast beds of phosphatic deposits in Florida, North Carolina, Tennessee, and Virginia. The state of trade, magnitude of crops, and the vigor of commerce also affect, in a marked degree, the cost of the raw materials of commercial fertilizers.

=5. Trade Values of Fertilizing Ingredients in Raw Materials and Chemicals.=—The values proposed by the Massachusetts Experiment Station are given below.[2]

Cents per pound. Nitrogen in ammonia salts, 19 “ “ nitrates, 14½

Organic nitrogen in dry and fine-ground fish, meat, blood, and in high-grade mixed fertilizers, 18½ “ “ “ cottonseed meal, linseed meal, and castor pomace, 15 “ “ “ fine-ground bone and tankage, 16½

“ “ “ fine-ground medium bone and tankage, 15 “ “ “ medium bone and tankage, 12 “ “ “ coarse bone and tankage, 7 “ “ “ hair, horn shavings, and coarse fish scraps, 7

Phosphoric acid soluble in water, 6 “ “ soluble in ammonium citrate, 5½ “ “ in fine bone and tankage, 5½ “ “ in fine medium bone and tankage, 4½ “ “ in medium bone and tankage, 3 “ “ in coarse bone and tankage, 2 “ “ in fine-ground fish, cottonseed meal, linseed meal, castor pomace, and wood-ashes, 5 “ “ insoluble (in ammonium citrate) in mixed fertilizers, 2

Potash as high-grade sulfate, and in mixtures free from muriate, 5 “ “ muriate, 4½ The manurial constituents contained in feed stuffs are valued as follows: Organic nitrogen, 15 Phosphoric acid, 5 Potash, 5

The organic nitrogen in superphosphates, special manures, and mixed fertilizers of a high grade is usually valued at the highest figures laid down in the trade values of fertilizing ingredients in raw materials; namely, eighteen and one-half cents per pound, it being assumed that the organic nitrogen is derived from the best sources; _viz._, animal matter, as meat, blood, bones, or other equally good forms, and not from leather, shoddy, hair, or any low-priced, inferior form of vegetable matter, unless the contrary is evident. In such materials the insoluble phosphoric acid is valued at two cents a pound. These values change as the markets vary.

The scheme of valuation prepared by the Massachusetts station does not include phosphoric acid in basic slags. By many experimenters the value of the acid in this combination, tetracalcium phosphate, is fully equal to that in superphosphates soluble in water and ammonium citrate. It would perhaps be safe to assign that value to all the phosphoric acid in basic slags soluble in a five per cent citric acid solution.

Untreated fine-ground phosphates, especially of the soft variety, so abundant in many parts of Florida, have also a high manurial value when applied to soils of an acid nature or rich in humus. On other soils of a sandy nature, or rich in calcium carbonate, such a fertilizer would have little value. The analyst in giving an opinion respecting the commercial value of a fertilizer, must be guided not only by the source of the material, its fineness or state of decomposition, and its general physical qualities, but also by the nature of the crop which it is to nourish and the kind of soil to which it is to be applied.

GENERAL ANALYTICAL PROCESSES.

=6. Taking Samples.=—It is impracticable to give definite directions for taking samples of fertilizers which will be applicable to all kinds of material and in all circumstances. If the chemist himself have charge of the taking of the sample, it will probably be sufficient to say that it should accurately represent the total mass of material sampled. Generally the samples which are brought to the chemist have been taken without his advice or direction and he is simply called upon to make an analysis of them.

=7. Minerals Containing Fertilizing Materials.=—When possible, the samples should be accompanied by a description of the mines where they are procured and a statement of the geologic conditions in which the deposits were made. As large a quantity of the material as can be conveniently obtained and transported should be secured. Where a large quantity of mineral matter is at hand it should first be put through a crusher. Many forms of crusher, driven by hand and other power, are on the market. Among these may be mentioned the Alden, Blake, Bisworth, Forster, and Lipsay machines.[3] They are all constructed essentially on the same principle, the pieces of mineral being broken into small fragments between two heavy vibrating steel plates. The general form of these instruments is seen in Fig. 1.

The fragments coming from the crusher can be reduced to a coarse powder by means of the iron plate and crusher shown in Fig. 2.

Where only a small quantity of mineral is at hand the apparatus just mentioned may be used at once after breaking the sample into small fragments by means of a hammer.

Finally the sample, if to be dissolved in an acid or soluble materials only, is reduced to a powder in an iron mortar until it will pass a sieve with a one or, better, one-half millimeter circular mesh. The powder thus obtained must be stirred with a magnet to remove all iron particles that may have been incorporated with the mass by abrasion of the instruments employed.

If a complete mineral analysis of the sample is to be secured, the material freed from iron, as above described, is to be rubbed to an impalpable powder in an agate mortar.

=8. Mixed Fertilizers.=—In fertilizing materials in bulk, the first requisite is that they shall be thoroughly mixed so that a given volume of the material may represent, practically, definite quantities of the materials sampled. The finer the material is, in the original state, and the more thoroughly it has been mixed, the better the sample will be. If the sample be already in sacks it will be sufficient to take portions by means of the ordinary trier, such as is used for sampling sugar and other substances. This consists of a long metal implement such as would be formed by a longitudinal section of a tube. The end is pointed and suited for penetrating into the sack and the materials contained therein. On withdrawing it, the semi-circular concavity is found filled with the material sampled. Samples in this way should be taken from various parts of the sack and these samples well mixed together and a subsample of the amount necessary to be taken to the laboratory can then be obtained.

=9. Method of the French Experiment Stations.=—In the method employed by the French Experiment Stations it is directed that in no case should stones or other foreign particles be removed from the fertilizer sampled, but they should enter into the sample taken in, as nearly as possible, the same proportions as they exist in the whole mass.

In the case of stones or other solid masses which are to be sampled, as many samples as possible should be taken from all parts of the heap and these should be reduced to a coarse powder, thoroughly mixed together and sampled.