I do not think we have any satisfactory evidence to prove that 3 tons of clover-hay and a ton of corn fed to a lot of fattening-sheep will afford a quantity of manure containing any more plant-food than the same kind and amount of food fed to a lot of fattening-cattle. The experiments of Lawes & Gilbert indicate that if there is any difference it is in favor of the ox. See Appendix, page 343. But it may well be that it is much easier to save the manure from the sheep than from the cattle. And so, practically, sheep may be better manure-makers than cattle—for the simple reason that less of the urine is lost.
“As a rule,” said the Doctor, “the dung of sheep contains far less water than the dung of cattle, though when you slop your breeding ewes to make them give more milk, the dung differs but little in appearance from that of cows. Ordinarily, however, sheep-dung is light and dry, and, like horse-dung, will ferment much more rapidly than cow or pig-dung. In piling manure in the winter or spring, special pains should be used to mix the sheep and horse-manure with the cow and pig-manure. And it may be remarked that for any crop or for any purpose where stable-manure is deemed desirable, sheep-manure would be a better substitute than cow or pig-manure.”
The dry matter of hog-manure, especially the urine, is rich in nitrogen, but it is mixed with such a large quantity of water that a ton of hog-manure, as it is usually found in the pen, is less valuable than a ton of horse or sheep-manure, and only a little more valuable than a ton of cow-manure.
As I have before said, my own plan is to let the store-hogs sleep in a basement-cellar, and bed them with horse and sheep-manure. I have this winter over 50 sows under the horse-stable, and the manure from 8 horses keeps them dry and comfortable, and we are not specially lavish with straw in bedding the horses.
During the summer we aim to keep the hogs out in the pastures and orchards as much as possible. This is not only good for the health of the pigs, but saves labor and straw in the management of the manure. It goes directly to the land. The pigs are good grazers and distribute the manure as evenly over the land as sheep—in fact, during hot weather, sheep are even more inclined to huddle together under the trees, and by the side of the fence, than pigs. This is particularly the case with the larger breeds of sheep.
In the winter it is not a difficult matter to save all the liquid and solid excrements from pigs, provided the pens are dry and no water comes in from the rain and snow. As pigs are often managed, this is the real difficulty. Pigs void an enormous quantity of water, especially when fed on slops from the house, whey, etc. If they are kept in a pen with a separate feeding and sleeping apartment, both should be under cover, and the feeding apartment may be kept covered a foot or so thick with the soiled bedding from the sleeping apartment. When the pigs get up in a morning, they will go into the feeding apartment, and the liquid will be discharged on the mass of manure, straw, etc.
“Dried muck,” said the Deacon, “comes in very handy about a pig-pen, for absorbing the liquid.”
“Yes,” said I, “and even dry earth can be used to great advantage, not merely to absorb the liquid, but to keep the pens sweet and healthy. The three chief points in saving manure from pigs are: 1, To have the pens under cover; 2, to keep the feeding apartment or yard covered with a thick mass of strawy manure and refuse of any kind, and 3, to scatter plenty of dry earth or dry muck on the floor of the sleeping apartment, and on top of the manure in the feeding apartment.”
“You feed most of your pigs,” said the Deacon, “out of doors in the yard, and they sleep in the pens or basement cellars, and itseems to me to be a good plan, as they get more fresh air and exercise than if confined.”
“We do not lose much manure,” said I, “by feeding in the yards. You let a dozen pigs sleep in a pen all night, and as soon as they hear you putting the food in the troughs outside, they come to the door of the pen, and there discharge the liquid and solid excrements on the mass of manure left there on purpose to receive and absorb them. I am well aware that as pigs are often managed, we lose at least half the value of their manure, but there is no necessity for this. A little care and thought will save nearly the whole of it.”
The Deacon and I have just been weighing a bushel of different kinds of manure made on the farm. We made two weighings of each kind, one thrown in loose, and the other pressed down firm. The following is the result:
WEIGHT OF MANURE PER BUSHEL, AND PER LOAD OF 50 BUSHELS.
Fresh horse-manure free from straw
Fresh horse-manure free from straw, pressed
Fresh horse-manure, as used for bedding pigs
Fresh horse-manure, as used for bedding pigs, pressed
Horse-manure from pig cellar
Horse-manure from pig cellar, pressed
Pig-manure
Pig-manure, pressed
Pig-manure and dry earth
Sheep-manure from open shed
Sheep-manure from open shed, pressed
Sheep-manure from closed shed
Sheep-manure from closed shed, pressed
Fresh cow-dung, free from straw
Hen-manure
Hen-manure, pressed
“In buying manure,” said the Deacon, “it makes quite a difference whether the load is trod down solid or thrown loosely into the box. A load of fresh horse-manure, when trod down, weighs half as much again as when thrown in loose.”
“A load of horse-manure,” said Charley, “after it has been used for bedding pigs, weighs 3,600 lbs., and only 2,300 lbs. when it is thrown into the pens, and I suppose a ton of the ‘double-worked’ manure is fully as valuable as a ton of the fresh horse-manure. If so, 15 ‘loads’ of the pig-pen manure is equal to 24 ‘loads’ of the stable-manure.”
“A ton of fresh horse-manure,” said the Doctor, “contains about 9 lbs. of nitrogen; a ton of fresh cow-dung about 6 lbs.; a ton of fresh sheep-dung, 11 lbs., and a ton of fresh pig-manure, 12 lbs. But if the Deacon and you weighed correctly, a ‘load’ or cord of cow-manure would contain more nitrogen than a load of pressed horse-manure. The figures are as follows:
A load of 50 bushels of fresh horse-dung,pressed and free from straw contains
A load of fresh cow-dung
A load of fresh sheep-dung
A load of fresh pig-dung
“These figures,” said I, “show how necessary it is to look at this subject in all its aspects. If I was buying manuresby weight,I would much prefer a ton of sheep-manure, if it had been made under cover, to any other manure except hen-dung, especially if it contained all the urine from the sheep. But if buying manure by the load or cord, that from a covered pig-pen would be preferable to any other.”
I have never had any personal experience in the use of liquid manure to any crop except grass. At Rothamsted, Mr. Lawes used to draw out the liquid manure in a water-cart, and distribute it on grass land.
“What we want to know,” said the Deacon, “is whether the liquid from our barn-yards will pay to draw out. If it will, the proper method of using it can be left to our ingenuity.”
According to Prof. Wolff, a ton of urine from horses, cows, sheep, and swine, contains the following amounts of nitrogen, phosphoric acid, and potash, and, for the sake of comparison, I give the composition of drainage from the barn-yard, and also of fresh dung of the different animals:
TABLE SHOWING THE AMOUNT OF NITROGEN, PHOSPHORIC ACID, AND POTASH, IN ONE TON OF THE FRESH DUNG AND FRESH URINE OF DIFFERENT ANIMALS, AND ALSO OF THE DRAINAGE OF THE BARN-YARD.
The drainage from a barn-yard, it will be seen, contains a little more than half as much nitrogen as cow-dung; and it is probable that the nitrogen in the liquid is in a much more available condition than that in the dung. It contains, also, nearly five times as much potash as the dung. It would seem, therefore, that with proper arrangements for pumping and distributing, this liquid could be drawn a short distance with profit.
But whether it will or will not pay to cart away the drainage, it is obviously to our interest to prevent, as far as possible, any of the liquid from running to waste.
It is of still greater importance to guard against any loss of urine. It will be seen that, on the average, a ton of the urine of our domestic animals contains more than twice as much nitrogen as a ton of the dung.
Where straw, leaves, swamp-muck, or other absorbent materials are not sufficiently abundant to prevent any loss of urine, means should be used to drain it into a tank so located that the liquid can either be pumped back on to the manure when needed, or drawn away to the land.
“I do not see,” said the Deacon, “why horse and sheep-urine should contain so much more nitrogen and potash than that from the cow and pig.”
“The figures given by Prof. Wolff,” said I, “are general averages. The composition of the urine varies greatly. The richer the food in digestible nitrogenous matter, the more nitrogen will there be in the dry matter of the urine. And, other things being equal, the less water the animal drinks, the richer will the urine be in nitrogen. The urine from a sheep fed solely on turnips would contain little or no more nitrogen than the urine of a cow fed on turnips. An ox or a dry cow fed on grass would probably void no more nor no poorer urine than a horse fed on grass. The urine that Mr. Lawes drew out in a cart on to his grass-land was made by sheep that had one lb. each of oil-cake per day, and one lb. of chaffed clover-hay, and all the turnips they would eat. They voided a large quantity of urine, but as the food was rich in nitrogen, the urine was doubtless nearly or quite as rich as that analyzed by Prof. Wolff, though that probably contained less water.”
If I was going to draw out liquid manure, I should be very careful to spout all the buildings, and keep the animals and manure as much under cover as possible, and also feed food rich in nitrogen. In such circumstances, it would doubtless pay to draw the urine full as well as to draw the solid manure.
The composition of human excrements, as compared with the mean composition of the excrements from horses, cows, sheep, and swine, so far as the nitrogen, phosphoric acid, and potash are concerned, is as follows:
TABLE SHOWING THE AMOUNT OF NITROGEN, PHOSPHORIC ACID, AND POTASH, IN ONE TON OF FRESH HUMAN EXCREMENTS, AND IN ONE TON OF FRESH EXCREMENTS FROM HORSES, COWS, SHEEP, AND SWINE.
Mean of horse, cow, sheep, and swine
One ton of fresh fæces contains more than twice as much nitrogen, and more than three times as much phosphoric acid, as a ton of fresh mixed animal-dung. The nitrogen, too, is probably in a more available condition than that in common barnyard-dung; and we should not be far wrong in estimating 1 ton of fæces equal to 2½ tons of ordinary dung, or about equal in value to carefully preserved manure from liberally-fed sheep, swine, and fattening cattle.
“It is an unpleasant job,” said the Deacon, “but it pays well to empty the vaults at least twice a year.”
“If farmers,” said the Doctor, “would only throw into the vaults from time to time some dry earth or coal ashes, the contents of the vaults could be removed without any disagreeable smell.”
“That is so,” said I, “and even where a vault has been shamefully neglected, and is full of offensive matter, it can be cleaned out without difficulty and without smell. I have cleaned out a large vault in an hour. We were drawing manure from the yards with three teams and piling it in the field. We brought back a load of sand and threw half of it into the vault, and put the other half on one side, to be used as required. The sand and fæces were then, with a long-handled shovel, thrown into the wagon, and drawn to the pile of manure in the field, and thrown on to the pile, not more than two or three inches thick. The team brought back a load of sand, and so we continued until the work was done. Sand or dry earth is cheap, and we used all that was necessary to prevent the escape of any unpleasant gases, and to keep the material from adhering to the shovels or the wagon.”
“Human urine,” said the Doctor, “is richer in phosphoric acid,but much poorer in nitrogen and potash than the urine from horses, cows, sheep, and swine.”
“Some years ago,” said the Deacon, “Mr. H. E. Hooker, of Rochester, used to draw considerable quantities of urine from the city to his farm. It would pay better to draw out the urine from farm animals.”
“The figures given above,” said I, “showing the composition of human excrements, are from Prof. Wolff, and probably are generally correct. But, of course, the composition of the excrements would vary greatly, according to the food.”
It has been ascertained by Lawes and Gilbert that the amount of matter voided by an adult male in the course of a year is—fæces, 95 lbs.; urine, 1,049 lbs.; total liquid and solid excrements in the pure state, 1,144 lbs. These contain:
Dry substance—fæces, 23¾ lbs.; urine, 34½; total, 58¼ lbs.
Mineral matter—fæces, 2½ lbs.; urine, 12; total, 14½ lbs.
Carbon—fæces, 10 lbs.; urine, 12; total 22 lbs.
Nitrogen—fæces, 1.2 lbs.; urine, 10.8; total, 12 lbs.
Phosphoric acid—fæces, 0.7 lbs.; urine, 1.93; total, 2.63 lbs.
Potash—fæces, 0.24 lbs.; urine, 2.01; total, 2.25 lbs.
The amount of potash is given by Prof. E. Wolff, not by Lawes and Gilbert.
The mixed solid and liquid excrements, in the condition they leave the body, contain about 95 per cent of water. It would require, therefore, 20 tons of fresh mixed excrements, to make one ton ofdrynightsoil, or the entire amount voided by a mixed family of 43 persons in a year.
One hundred lbs. of fresh fæces contain 75 lbs. of water, and 25 lbs. of dry substance.
One hundred lbs. of fresh urine contain 96½ lbs. of water, and 3½ lbs. of dry substance.
One hundred lbs. of the dry substance of the fæces contain 5 lbs. of nitrogen, and 5½ lbs. of phosphates.
One hundred lbs. of the dry substance of the urine contain 27 lbs. of nitrogen, and 10¾ lbs. of phosphates.
These figures are from Lawes and Gilbert, and may be taken as representing the composition of excrements from moderately well-fed persons.
According to Wolff, a ton of fresh human urine contains 12 lbs. of nitrogen. According to Lawes and Gilbert, 18 lbs.
The liquid carted from the city by Mr. Hooker was from well-fed adult males, and would doubtless be fully equal to the figures given by Lawes and Gilbert. If we call the nitrogen worth 20 cents a lb.,and the phosphoric acid (soluble) worth 12½ cents, a ton of such urine would be worth,on the land, $1.06.
“A ton of the fresh fæces,” said the Deacon, “at the same estimate, would be worth (20 lbs. nitrogen, at 20 cents, $4; 21¾ lbs. phosphoric acid, at 12½ cents, $2.70), $6.70.”
“Not by a good deal,” said the Doctor. “The nitrogen and phosphoric acid in the urine are both soluble, and would be immediately available. But the nitrogen and phosphoric acid in the fæces would be mostly insoluble. We cannot estimate the nitrogen in the fæces at over 15 cents a lb., and the phosphoric acid at 5 cents. This would make the value of a ton of fresh fæces,on the land, $4.09.”
“This makes the ton of fæces worth about the same as a ton of urine. But I would like to know,” said the Deacon, “if you really believe we could afford to pay $4 per ton for the stuff delivered on the farm?”
“If we could get the genuine article,” said the Doctor, “it would be worth $4 a ton. But, as a rule, it is mixed with water, and dirt, and stones, and bricks, and rubbish of all kinds. Still, it is unquestionably a valuable fertilizer.”
“In the dry-earth closets,” said I, “such a large quantity of earth has to be used to absorb the liquid, that the material, even if used several times, is not worth carting any considerable distance. Dr. Gilbert found that 5 tons of absolutely dry earth, before using, contained 16.7 lbs. of nitrogen.
Dr. Vœlcker found that five tons of dry earth gained about 7 lbs. of nitrogen, and 11 lbs. of phosphoric acid, each time it was used in the closets. If we consider each lb. of nitrogen with the phosphoric acid worth 20 cents a lb., 5 tons of the dry earth, after being used once, would be worth $1.46, or less than 30 cents a ton, and after it had been used six times, five tons of the material would be worth $11.98, or about $2.40 per ton.
In this calculation I have not reckoned in the value of the nitrogen the soil contained before using. Soil, on a farm, is cheap.
It is clear from these facts that any earth-closet manure a farmer would be likely to purchase in the city has not a very high value. It is absurd to talk of making “guano” or any concentrated fertilizer out of the material from earth-closets.
“It is rather a reflection on our science and practical skill,” said the Doctor, “but it looks at present as though the only plan to adopt in large cities is to use enormous quantities of water and wash the stuff into the rivers and oceans for the use of aquatic plants and fishes. The nitrogen is not all lost. Some of it comes back to us in rains and dews. Of course, there are places where the sewage of our cities and villages can be used for irrigating purposes. But when water is used as freely as it ought to be used for health, the sewage is so extremely poor in fertilizing matter, that it must be used in enormous quantities, to furnish a dressing equal to an application of 20 tons of stable-manure per acre.”
“If,” continued the Doctor, “the sewage is used merely aswaterfor irrigating purposes, that is another question. The water itself may often be of great benefit. This aspect of the question has not received the attention it merits.”
Guano is the manure of birds that live principally on fish.
Fish contain a high percentage of nitrogen and phosphoric acid, and consequently when fish are digested and the carbon is burnt out of them, the manure that is left contains a still higher percentage of nitrogen and phosphoric acid than the fish from which it was derived.
Guano is digested fish. If the guano, or the manure from the birds living on fish, has been preserved without loss, it would contain not only a far higher percentage of nitrogen, but the nitrogen would be in a much more available condition, and consequently be more valuable than the fish from which the guano is made.
The difference in the value of guano is largely due to a difference in the climate and locality in which it is deposited by the birds. In a rainless and hot climate, where the bird-droppings would dry rapidly, little or no putrefaction or fermentation would take place, and there would be no loss of nitrogen from the formation and escape of ammonia.
In a damper climate, or where there was more or less rain, the bird-droppings would putrefy, and the ammonia would be liable to evaporate, or to be leached out by the rain.
Thirty years ago I saw a quantity of Peruvian guano that contained more than 18 per cent of nitrogen. It was remarkably light colored. You know that the white part of hen-droppings consists principally of uric acid, which contains about 33 per cent of nitrogen.
For many years it was not difficult to find guano containing 13 per cent of nitrogen, and genuine Peruvian guano was the cheapestand best source of available nitrogen. But latterly, not only has the price been advanced, but the quality of the guano has deteriorated. It has contained less nitrogen and more phosphoric acid. See the Chapter on “Value of Fertilizers,” Page 324.
“I wish,” said the Deacon, “you would tell us something about the ‘ammonia-salts’ and nitrate of soda so long used in Lawes and Gilbert’s experiments. I have never seen any of them.”
“You could not invest a little money to better advantage than to send for a few bags of sulphate of ammonia and nitrate of soda. You would then see what they are, and would learn more by using them, than I can tell you in a month. You use them just as you would common salt. As a rule, the better plan is to sow them broadcast, and it is important to distribute them evenly. In sowing common salt, if you drop a handful in a place, it will kill the plants. And so it is with nitrate of soda or sulphate of ammonia. Two or three pounds on a square rod will do good, but if you put half of it on a square yard, it will burn up the crop, and the other half will be applied in such a small quantity that you will see but little effect, and will conclude that it is a humbug. Judging from over thirty years’ experience, I am safe in saying that not one man in ten can be trusted to sow these manures. They should be sown with as much care as you sow grass or clover-seed.”
“The best plan,” said the Doctor, “is to mix them with sifted coal-ashes, or with gypsum, or sifted earth.”
“Perhaps so,” said I, “though there is nothing gained by mixing earth or ashes with them, except in securing a more even distribution. And if I was going to sow them myself, I would much prefer sowing them unmixed. Any man who can sow wheat or barley can sow sulphate of ammonia or nitrate of soda.”
“Lawes and Gilbert,” said the Deacon, “used sulphate and muriate of ammonia, and in one or two instances the carbonate of ammonia. Which is the best?”
“The one that will furnish ammonia or nitrogen at the cheapest rate,” said the Doctor, “is the best to use. The muriate of ammonia contains the most ammonia, but the sulphate, in proportion to the ammonia, is cheaper than the muriate, and far cheaper than the carbonate.”
Carbonate of ammonia contains 21½ per cent of ammonia.
Sulphate of ammonia contains 25¾ per cent of ammonia = 21⅕ of nitrogen.
Muriate of ammonia contains 31 per cent of ammonia = 25½ of nitrogen.
Nitrate of soda contains 16⅖ per cent of nitrogen.
Nitrate of potash, 13¾ per cent of nitrogen.
From these figures you can ascertain, when you know the price of each, which is the cheapest source of nitrogen.
“True,” said I, “but it must be understood that these figures represent the composition of a pure article. The commercial sulphate of ammonia, and nitrate of soda, would usually contain 10 per cent of impurities. Lawes and Gilbert, who have certainly had much experience, and doubtless get the best commercial articles, state that a mixture of equal parts sulphate and muriate of ammonia contains about 25 per cent of ammonia. According to the figures given by the Doctor, the mixture would contain, if pure, over 28 per cent of ammonia. In other words, 90 lbs. of the pure article contains as much as 100 lbs. of the commercial article.”
As to whether it is better, when you can buy nitrogen at the same price in nitrate of soda as you can in sulphate of ammonia, to use the one or the other will depend on circumstances. The nitrogen exists as nitric acid in the nitrate of soda, and as ammonia in the sulphate of ammonia. But there are good reasons to believe that before ammonia is used by the plants it is converted into nitric acid. If, therefore, we could apply the nitrate just where it is wanted by the growing crop, and when there is rain enough to thoroughly distribute it through the soil to the depth of six or eight inches, there can be little doubt that the nitrate, in proportion to the nitrogen, would have a quicker and better effect than the sulphate of ammonia.
“There is another point to be considered,” said the Doctor. “Nitric acid is much more easily washed out of the soil than ammonia. More or less of the ammonia enters into chemical combination with portions of the soil, and may be retained for months or years.”
When we use nitrate of soda, we run the risk of losing more or less of it from leaching, while if we use ammonia, we lose, for the time being, more or less of it from its becoming locked up in insoluble combinations in the soil. For spring crops, such as barley or oats, or spring wheat, or for a meadow or lawn, or for top-dressing winter-wheat in the spring, the nitrate of soda, provided it is sown early enough, or at any time in the spring, just previous to a heavy rain, is likely to produce a better effect than the sulphate of ammonia. But for sowing in the autumn on winter-wheat the ammonia is to be preferred.
“Saltpetre, or nitrate of potash,” said the Deacon, “does not contain as much nitrogen as nitrate of soda.”
“And yet,” said the Doctor, “if it could be purchased at the same price, it would be the cheaper manure. It contains 46½ per cent of potash, and on soils, or for crops where potash is needed, we may sometimes be able to purchase saltpetre to advantage.”
“If I could come across a lot of damaged saltpetre,” said I, “that could be got for what it is worth as manure, I should like to try it on my apple trees—one row with nitrate of soda, and one row with nitrate of potash. When we apply manure to apple trees, the ammonia, phosphoric acid, and potash, are largely retained in the first few inches of surface soil, and the deeper roots get hold of only those portions which leach through the upper layer of earth. Nitric acid, however, is easily washed down into the subsoil, and would soon reach all the roots of the trees.”
Bone-dust is often spoken of as a phosphatic manure, and it has been supposed that the astonishing effect bone-dust sometimes produces on old pasture-land, is due to its furnishing phosphoric acid to the soil.
But it must be remembered that bone-dust furnishes nitrogen as well as phosphoric acid, and we are not warranted in ascribing the good effect of bones to phosphoric acid alone.
Bones differ considerably in composition. They consist essentially of gelatine and phosphate of lime. Bones from young animals, and the soft porous parts of all bones, contain more gelatine than the solid parts, or the bones from older animals. On the average, 1,000 lbs. of good commercial bone-dust contains 38 lbs. of nitrogen.
On the old dairy farms of Cheshire, where bone-dust produced such marked improvement in the quantity and quality of the pastures and meadows, it was usual to apply from 4,000 to 5,000 lbs. per acre, and often more. In other words, a dressing of bone-dustfrequently contained 200 lbs. of nitrogen per acre—equal to 20 or 25 tons of barn-yard manure.
“It has been supposed,” said the Doctor, “that owing to the removal of so much phosphoric acid in the cheese sold from the farm, that the dairy pastures of Cheshire had been exhausted of phosphoric acid, and that the wonderful benefits following an application of bone-dust to these pastures, was due to its supplying phosphoric acid.”
“I do not doubt,” said I, “the value of phosphoric acid when applied in connection with nitrogen to old pasture lands, but I contend that the experience of the Cheshire dairymen with bone-dust is no positive proof that their soils were particularly deficient in phosphoric acid. There are many instances given where the gelatine of the bones, alone, proved of great value to the grass. And I think it will be found that the Cheshire dairymen do not find as much benefit from superphosphate as they did from bone-dust. And the reason is, that the latter, in addition to the phosphoric acid, furnished a liberal dressing of nitrogen. Furthermore, it is not true that dairying specially robs the soil of phosphoric acid. Take one of these old dairy farms in Cheshire, where a dressing of bone-dust, according to a writer in the Journal of the Royal Agricultural Society, has caused ‘a miserable covering of pink grass, rushes, and a variety of other noxious weeds, to give place to the most luxuriant herbage of wild clover, trefoil, and other succulent and nutritious grasses.’ It is evident from this description of the pastures before the bones were used, that it would take at least three acres to keep a cow for a year.”
“I have known,” says the same writer quoted above, “many a poor, honest, but half broken-hearted man raised from poverty to comparative independence, and many a sinking family saved from inevitable ruin by the help of this wonderful manure.” And this writer not only spoke from observation and experience, but he showed his faith by his works, for he tells us that he had paid nearly $50,000 for this manure.
Now, on one of these poor dairy farms, where it required 3 acres to keep a cow, and where the grass was of poor quality, it is not probable that the cows produced over 250 lbs. of cheese in a year. One thousand pounds of cheese contains, on the average, about 45½ lbs. of nitrogen; 2½ lbs. of potash, and 11½ lbs. of phosphoric acid. From this it follows, if 250 lbs. of cheese are sold annually from three acres of pasture, less than one lb. of phosphoric acid per acre is exported from the farm in the cheese.
One ton of timothy-hay contains nearly 14½ lbs. of phosphoricacid. And so a farmer who raises a ton of timothy-hay per acre, and sells it, sends off as much phosphoric acid in one year as such a Cheshire dairyman as I have alluded to did in fourteen years.
What the dairymen want, and what farmers generally want, is nitrogenandphosphoric acid. Bone-dust furnishes both, and this was the reason of its wonderful effects.
It does not follow from this, that bone-dust is the cheapest and best manure we can use. It is an old and popular manure, and usually commands a good price. It sells for all it is worth. A dozen years ago, I bought ten tons of bone-dust at $18 per ton. I have offered $25 per ton since for a similar lot, but the manufacturers find a market in New York for all they can make.
Bone-dust, besides nitrogen, contains about 23 per cent of phosphoric acid.
“That does not give me,” said the Deacon, “any idea of its value.”
“Let us put it in another shape, then,” said I. “One ton of good bone-dust contains about as much nitrogen as 8½ tons of fresh stable-manure, and as much phosphoric acid as 110 tons of fresh stable-manure. But one ton of manure contains more potash than 5 tons of bone-dust.”
Bone-dust, like barnyard-manure, does not immediately yield up its nitrogen and phosphoric acid to plants. The bone phosphate of lime is insoluble in water, and but very slightly soluble in water containing carbonic acid. The gelatine of the bones would soon decompose in a moist, porous, warm soil, provided it was not protected by the oil and by the hard matter of the bones. Steaming, by removing the oil, removes one of the hindrances to decomposition. Reducing the bones as fine as possible is another means of increasing their availability.
Another good method of increasing the availability of bone-dust is to mix it with barnyard-manure, and let both ferment together in a heap. I am inclined to think this the best, simplest, and most economical method of rendering bone-dust available. The bone-dust causes the heap of manure to ferment more readily, and the fermentation of the manure softens the bones. Both the manure and the bones are improved and rendered richer and more available by the process.
Another method of increasing the availability of bone-dust is by mixing it with sulphuric acid.
The phosphate of lime in bones is insoluble in water, though rain water containing carbonic acid, and the water in soils, slowly dissolve it. By treating the bones with sulphuric acid, the phosphate of lime is decomposed and rendered soluble. Consequently, bone-dust treated with sulphuric acid will act much more rapidly than ordinary bone-dust. The sulphuric acid does not make it anyricherin phosphoric acid or nitrogen. It simply renders them more available.
“And yet,” said the Doctor, “the use of sulphuric acid for ‘dissolving’ bones, or rather phosphate of lime, introduced a new era in agriculture. It is the grand agricultural fact of the nineteenth century.”
“It is perhaps not necessary,” said I, “to give any direction for treating bones with sulphuric acid. We have got beyond that. We can now buy superphosphate cheaper than we can make it from bones.”
“But is it as good?” asked the Deacon.
“Soluble phosphate of lime,” said I, “is soluble phosphate of lime, and it makes no difference whether it is made from burnt bones, or from phosphatic guano, or mineral phosphate. That question has been fully decided by the most satisfactory experiments.”
“Before you and the Deacon discuss that subject,” said the Doctor, “it would be well to tell Charley what superphosphate is.”
“I wish you would tell me,” said Charley.
“Well,” said the Doctor, “phosphate of lime, as it exists in bones, is composed of three atoms of lime and one atom of phosphoric acid. Chemists call it the tricalcic phosphate. It is also called the basic phosphate of lime, and not unfrequently the ‘bone-earth phosphate.’ It is the ordinary or common form of phosphate of lime, as it exists in animals, and plants, and in the various forms of mineral phosphates.
“Then there is another phosphate of lime, called the dicalcic phosphate, or neutral phosphate of lime, or reverted phosphate of lime. It is composed of one atom of water, two atoms of lime, and one atom of phosphoric acid.
“Then we have what we call superphosphate, or acid phosphate of lime, or more properly monocalcic phosphate. It is composed of two atoms of water, one atom of lime, and one atom of phosphoric acid. This acid phosphate of limeis soluble in water.
“The manufacture of superphosphate of lime is based on these facts. Theone-limephosphate is soluble, thethree-limephosphate is insoluble. To convert the latter into the former, all we have to do is totake away two atoms of lime.
“Sulphuric acid has a stronger affinity for lime than phosphoric acid. And when you mix enough sulphuric acid with finely ground three-lime phosphate, to take away two atoms of lime, you get the phosphoric acid united with one atom of lime and two atoms of water.”
“And what,” asked the Deacon, “becomes of the two atoms of lime?”
“They unite with the sulphuric acid,” said the Doctor, “and form plaster, gypsum, or sulphate of lime.”
“The molecular weight of water,” continued the Doctor, “is 18; of lime, 56; of sulphuric acid, 80; of phosphoric acid, 142.
“An average sample of commercial bone dust,” continued the Doctor, “contains about 50 per cent of phosphate of lime. If we take 620 lbs. of finely-ground bone-dust, containing 310 lbs. of three-lime phosphate, and mix with it 160 lbs. of sulphuric acid (say 240 lbs. common oil of vitriol, sp. gr. 1.7), the sulphuric acid will unite with 112 lbs. of lime, and leave the 142 lbs. of phosphoric acid united with the remaining 56 lbs. of lime.”
“And that will give you,” said the Deacon, “780 lbs. of ‘dissolved bones,’ or superphosphate of lime.”
“It will give you more than that,” said the Doctor, “because, as I said before, the two atoms of lime (112 lbs.) are replaced by two atoms (36 lbs.) of water. And, furthermore, the two atoms of sulphate of lime produced, contained two atoms (36 lbs.) of water. The mixture, therefore, contains, even when perfectly dry, 72 lbs. of water.”
“Where does this water come from?” asked the Deacon.
“When I was at Rothamsted,” said I, “the superphosphate which Mr. Lawes used in his experiments was made on the farm from animal charcoal, or burnt bones, ground as fine as possible—the finer the better. We took 40 lbs. of the meal, and mixed it with 20 lbs. of water, and then poured on 30 lbs. of common sulphuric acid (sp. g. 1.7), and stirred it up rapidly and thoroughly, and then threw it out of the vessel into a heap, on the earth-floor in the barn. Then mixed another portion, and so on, until we had the desired quantity, say two or three tons. The last year I was at Rothamsted, we mixed 40 lbs. bone-meal, 30 lbs. water, and 30 lbs. acid; and we thought the additional water enabled us to mix the acid and meal together easier and better.”
“Dr. Habirshaw tells me,” said the Doctor, “that in making the ‘Rectified Peruvian Guano’ no water is necessary, and none is used. The water in the guano and in the acid is sufficient tofurnish the two atoms of water for the phosphate, and the two atoms for the sulphate of lime.”
“Such is undoubtedly the case,” said I, “and when large quantities of superphosphate are made, and the mixing is done by machinery, it is not necessary to use water. The advantage of using water is in the greater ease of mixing.”
“Bone-dust,” said the Doctor, “contains about 6 per cent of water, and the sulphuric acid (sp. g. 1.7) contains about one-third its weight of water. So that, if you take 620 lbs. of bone-dust, and mix with it 240 lbs. of common sulphuric acid, you have in the mixture 117 lbs. of water, which is 45 lbs. more than is needed to furnish the water of combination.”
“The superphosphate produced from 620 lbs. of bones, therefore,” continued the Doctor, “would contain:
* Containing nitrogen, 23½ lbs.
“There is a small quantity of carbonate of lime in the bones,” said I, “which would take up a little of the acid, and you will have a remarkably good article if you calculate that the 620 lbs. of bone-dust furnish you half a ton (1,000 lbs.) of superphosphate. It will be a better article than it is practically possible to make.”
“Assuming that it made half a ton,” said the Doctor, “it would contain 14¼ per cent of soluble phosphoric acid, and 2⅓ per cent of nitrogen.”
“With nitrogen at 20 cents per lb., and soluble phosphoric acid at 12½ c. per lb., this half ton of superphosphate, made from 620 lbs. of good bone-dust, would be worth $22.50, or $45 per ton.”
“Or, to look at it in another light,” continued the Doctor, “a ton of bone-dust, made into such a superphosphate as we are talking about, would be worth $72.58.”
“How much,” asked the Deacon, “would a ton of the bone-dust be considered worth before it was converted into superphosphate?”
“A ton of bone-dust,” replied the Doctor, “contains 76 lbs. of nitrogen, worth, at 18 cents per lb., $13.68, and 464 lbs. phosphoric acid, worth 7 cents per lb., $32.48. In other words, a ton of bone-dust, at the usual estimate, is worth $46.16.”
“And,” said the Deacon, “after it is converted into superphosphate, the same ton of bones is worth $72.58. It thus appears that you pay $26.42 per ton for simply making the phosphoric acid in a ton of bones soluble.Isn’tit paying a little too much for the whistle?”
“Possibly such is the case,” said I, “and in point of fact, I think bone-dust, especially from steamed or boiled bones, can be used with more economy in its natural state than in the form of superphosphate.”
Superphosphate can be made more economically from mineral phosphates than from bones—the nitrogen, if desired, being supplied from fish-scrap or from some other cheap source of nitrogen.
But for my own use I would prefer to buy a good article of superphosphate of lime, containing no nitrogen, provided it can be obtained cheap enough. I would buy the ammoniacal, or nitrogenous manure separately, and do my own mixing—unless the mixture could be bought at a less cost than the same weight of soluble phosphoric acid, and available nitrogen could be obtained separately.
A pure superphosphate—and by pure I mean a superphosphate containing no nitrogen—can be drilled in with the seed without injury, but I should be a little afraid of drilling in some of the ammoniacal or nitrogenous superphosphates with small seeds.
And then, again, the “nitrogen” in a superphosphate mixture may be in the form of nitric acid, or sulphate of ammonia, in one case, or, in another case, in the form of hair, woollen rags, hide, or leather. It is far more valuable as nitric acid or ammonia, because it will act quicker, and if I wanted hair, woollen rags, horn-shavings, etc., I would prefer to have them separate from the superphosphate.
Twenty five to thirty years ago, much was said in regard to special manures. Fertilizers were prepared for the different crops with special reference to the composition of the plants.
“But it was known then, as now,” said the Doctor, “that all our agricultural plants were composed of the same elements.”
“True, but what was claimed was this: Some crops contain, forinstance, more phosphoric acid than other crops, and for these a manure rich in phosphoric acid was provided. Others contained a large proportion of potash, and these were called ‘potash crops,’ and the manure prescribed for them was rich in potash. And so with the other ingredients of plants.”
“I recollect it well,” said the Doctor, “and, in truth, for several years I had much faith in the idea. It was advocated with consummate ability by the lamented Liebig, and in fact a patent was taken out by the Musgraves, of Liverpool, for the manufacture of Liebig’s Special Manures, based on this theory. But the manures, though extensively used by the leading farmers of England, and endorsed by the highest authorities, did not in the end stand the test of actual farm practice, and their manufacture was abandoned. And I do not know of any experienced agricultural chemist who now advocates this doctrine of special manures.
“Dr. Vœlcker says: ‘The ash-analyses of plants do not afford a sufficiently trustworthy guide to the practical farmer in selecting the kind of manure which is best applied to each crop.’”
“Never mind the authorities,” said the Deacon; “what we want are facts.”
“Well,” replied the Doctor, “take the wheat and turnip crop as an illustration.
“We will suppose that there is twice the weight of wheat-straw as of grain; and that to 10 tons of bulbs there is 3 tons of turnip-tops. Now, 100 lbs. each of the ash of these two crops contain:
“There are other ingredients,” continued the Doctor, “but these are the most important.
“Now, if you were going to compound a manure for wheat, say 100 lbs., consisting of potash and phosphoric acid, what would be the proportions?”
The Deacon figured for a few moments, and then produced the following table:
“Exactly,” said the Doctor, “and yet the experiments of Lawesand Gilbert clearly prove that a soil needs to be richer in available phosphoric acid, to produce even a fair crop of turnips, than to produce a large crop of wheat. And the experience of farmers everywhere tends in the same direction. England is the greatest turnip-growing country in the world, and you will find that where one farmer applies potash to turnips, or superphosphate to wheat, a hundred farmers use superphosphate as a special manure for the turnip crop.”
“And we are certainly warranted in saying,” continued the Doctor, “that the composition of a plant affords, in practical agriculture, and on ordinary cultivated soils,no sort of indication as to the composition of the manure it is best to apply to the crop.”
“Again,” continued the Doctor, “if the theory was a correct one, it would follow that those crops which contained the most nitrogen, would require the most nitrogen in the manure. Beans, peas, and clover would require a soil or a manure richer in available nitrogen than wheat, barley, or oats. We know that thevery reverseis true—know it from actual, and repeated, and long-continued experiments like those of Lawes and Gilbert, and from the common experience of farmers everywhere.”
“You need not get excited,” said the Deacon, “the theory is a very plausible one, and while I cannot dispute your facts, I must confess I cannot seewhyit is not reasonable to suppose that a plant which contains a large amount of nitrogen should not want a manure specially rich in nitrogen; or why turnips which contain so much potash should not want a soil or manure specially rich in potash.”
“Do you recollect,” said I, “that crop of turnips I raised on a poor blowing-sand?”
“Yes,” said the Deacon, “it was the best crop of turnips I ever saw grow.”
“That crop of turnips,” said I, “was due to a dressing of superphosphate of lime, with little or no potash in it.”
“I know all that,” said the Deacon. “I admit the fact that superphosphate is a good manure for turnips. What I want to know is the reason why superphosphate is better for turnips than for wheat?”
“Many reasons might be given,” said the Doctor; “Prof. Vœlcker attributes it to the limited feeding range of the roots of turnips, as compared to wheat. ‘The roots of wheat,’ says Prof. Vœlcker, ‘as is well known, penetrate the soil to a much greater depth than the more delicate feeding fibres of the roots of turnips. Wheat, remaining on the ground two or three months longer thanturnips, can avail itself for a longer period of the resources of the soil; therefore in most cases the phosphoric acid disseminated through the soil is amply sufficient to meet the requirements of the wheat crop; whilst turnips, depending on a thinner depth of soil during their shorter period of growth, cannot assimilate sufficient phosphoric acid, to come to perfection.’This is, I believe, the main reason why the direct supply of readily available phosphates is so beneficial to root-crops, and not to wheat.”
“This reason,” said I, “has never been entirely satisfactory to me. If the roots of the turnip have such a limited range, how are they able to get such a large amount of potash?
“It is probable that the turnip, containing such a large relative amount of potash and so little phosphoric acid, has roots capable of absorbing potash from a very weak solution, but not so in regard to phosphoric acid.”
“There is another way of looking at this matter,” said the Doctor. “You must recollect that, if turnips and wheat were growing in the same field, both plants get their food from the same solution. And instead of supposing that the wheat-plant has the power of taking up more phosphoric acid than the turnip-plant, we may suppose that the turnip has the power of rejecting or excluding a portion of phosphoric acid. It takes up no more potash than the wheat-plant, but it takeslessphosphoric acid.”
But it is not necessary to speculate on this matter. For the present we may accept the fact, that the proportion of potash, phosphoric acid, and nitrogen in the crop is no indication of the proper proportion in which these ingredients should be applied to the soil for these crops in manure.
It may well be that we should use special manures for special crops; but we must ascertain what these manures should be, not from analyses of the crops to be grown, but from experiment and experience.
So far as present facts throw light on this subject, we should conclude that those crops which contain theleastnitrogen are the most likely to be benefited by its artificial application; and the crops containing the most phosphoric acid, are the crops to which, in ordinary practical agriculture, it will be unprofitable to apply superphosphate of lime.
“That,” said the Doctor, “may be stating the case a little too strong.”
“Perhaps so,” said I, “but you must recollect I am now speaking of practical agriculture. If I wanted to raise a good crop of cabbage, I should not think of consulting a chemical analysisof the cabbage. If I set out cabbage on an acre of land, which, without manure, would produce 16 tons of cabbage, does any one mean to tell me that if I put the amount of nitrogen, phosphoric acid and potash which 10 tons of cabbage contain, on an adjoining acre, that it would produce an extra growth of 10 tons of cabbage. I can not believe it. The facts are all the other way. Plant growth is not such a simple matter as the advocates of this theory, if there be any at this late day, would have us believe.”
In 1857, Prof. S. W. Johnson, in his Report to the Connecticut Agricultural Society, adopted the following valuation:
Analyses of many of the leading commercial fertilizers at that time showed that, when judged by this standard, the price charged was far above their actual value. In some cases, manures selling for $60 per ton, contained nitrogen, phosphoric acid, and potash worth only from $20 to $25 per ton. And one well-known manure, which sold for $28 per ton, was found to be worth only $2.33 per ton. A Bone Fertilizer selling at $50 per ton, was worth less than $14 per ton.
“In 1852,” said the Doctor, “superphosphate of lime was manufactured by the New Jersey Zinc Co., and sold in New York at $50 per ton of 2,000 lbs. At the same time, superphosphate of lime made from Coprolites, was selling in England for $24 per ton of 2,240 lbs. The late Prof. Mapes commenced making “Improved Superphosphate of Lime,” at Newark, N.J., in 1852, and Mr. De Burg, the same year, made a plain superphosphate of lime in Brooklyn, N.Y. The price, in proportion to value, was high, and, in fact, the same may be said of many of our superphosphate manures, until within the last few years.”
Notwithstanding the comparatively high price, and the uncertain quality of these commercial manures, the demand has been steadily on the increase. We have now many honorable and intelligentmen engaged in the manufacture and sale of these artificial manures, and owing to more definite knowledge on the part of the manufacturers and of the purchasers, it is not a difficult matter to find manures well worth the money asked for them.
“A correct analysis,” said I, “furnishes the only sure test of value. ‘Testimonials’ from farmers and others are pre-eminently unreliable. With over thirty years’ experience in the use of these fertilizers, I would place far more confidence on a good and reliable analysis than on any actual trial I could make in the field. Testimonials to a patent fertilizer are about as reliable as testimonials to a patent-medicine. In buying a manure, we want to know what it contains, and the condition of the constituents.”
In 1877, Prof. S. W. Johnson gives the following figures, showing “the trade-values, or cost in market, per pound, of the ordinary occurring forms of nitrogen, phosphoric acid, and potash, as recently found in the New York and New England markets:
Nitrogen in ammonia and nitrates
Nitrogen in Peruvian Guano, fine steamed bone, dried and fine ground blood, meat, and fish
Nitrogen in fine ground bone, horn, and wool-dust
Nitrogen in coarse bone, horn-shavings, and fish-scrap
Phosphoric acid soluble in water
Phosphoric acid“reverted,” and in Peruvian Guano
Phosphoric acidinsoluble, in fine bone and fish guano
Phosphoric acid insoluble,in coarse bone, bone-ash, and bone-black
Phosphoric acid insoluble,in fine ground rock phosphate
Potash in high-grade sulphate
Potashin kainit, as sulphate
Potashin muriate, or potassium chloride
“These ‘estimated values,’” says Prof. Johnson, “are not fixed, but vary with the state of the market, and are from time to time subject to revision. They are not exact to the cent or its fractions, because the same article sells cheaper at commercial or manufacturing centers than in country towns, cheaper in large lots than in small, cheaper for cash than on time. These values are high enough to do no injustice to the dealer, and accurate enough to serve the object of the consumer.
“By multiplying the per cent of Nitrogen, etc., by the trade-value per pound, and then by 20, we get the value per ton of the several ingredients, and adding the latter together, we obtain the total estimated value per ton.
“The uses of the ‘Valuation’ are, 1st, to show whether a given lot or brand of fertilizer is worth as a commodity of trade what it costs. If the selling price is no higher than the estimated value,the purchaser may he quite sure that the price is reasonable. If the selling price is but $2 to $3 per ton more than the estimated value, it may still be a fair price, but if the cost per ton is $5 or more over the estimated value, it would be well to look further. 2d, Comparisons of the estimated values, and selling prices of a number of fertilizers will generally indicate fairly which is the best for the money. But the ‘estimated value’ is not to be too literally construed, for analysis cannot always decide accurately what is theformof nitrogen, etc., while the mechanical condition of a fertilizer is an item whose influence cannot always be rightly expressed or appreciated.
“TheAgricultural valueof a fertilizer is measured by the benefit received from its use, and depends upon its fertilizing effect, or crop-producing power. As a broad general rule it is true that Peruvian guano, superphosphates, fish-scraps, dried blood, potash salts, plaster, etc., have a high agricultural value which is related to their trade-value, and to a degree determines the latter value. But the rule has many exceptions, and in particular instances the trade-value cannot always be expected to fix or even to indicate the agricultural value. Fertilizing effect depends largely upon soil, crop, and weather, and as these vary from place to place, and from year to year, it cannot be foretold or estimated except by the results of past experience, and then only in a general and probable manner.”
“It will be seen,” said the Doctor, “that Prof. Johnson places a higher value on potash now than he did 20 years ago. He retains the same figures for soluble phosphoric acid, and makes a very just and proper discrimination between the different values of different forms of nitrogen and phosphoric acid.”
“The prices,” said I, “are full as high as farmers can afford to pay. But there is not much probability that we shall see them permanently reduced. The tendency is in the other direction. In a public address Mr. J. B. Lawes has recently remarked: ‘A future generation of British farmers will doubtless hear with some surprise that, at the close of the manure season of 1876, there were 40,000 tons of nitrate of soda in our docks, which could not find purchasers, although the price did not exceed £12 or £13 per ton.’”
“He evidently thinks,” said the Doctor, “that available nitrogen is cheaper now than it will be in years to come.”
“Nitrate of soda,” said I, “at the prices named, is only 2½ to 2¾ cents per lb., and the nitrogen it contains would cost less than 18 cents per lb., instead of 24 cents, as given by Prof. Johnson.”
“No. 1 Peruvian Guano, ‘guaranteed,’ is now sold,” said theDoctor, “at a price per ton, to be determined by its composition, at the following rates:
Nitrogen (ammonia, 17½ c.)
Soluble phosphoric acid
Reverted phosphoric acid
Insoluble phosphoric acid
Potash, as sulphate and phosphate
“The first cargo of Peruvian guano, sold under this guarantee, contained:
Estimated retail price per ton of 2,000 lbs.
Marked on bags for sale
The second cargo, sold under this guarantee, contained:
Selling price marked on bags
“It is interesting,” said I, “to compare these analyses of Peruvian guano of to-day, with Peruvian guano brought to England twenty-nine or thirty years ago. I saw at Rothamsted thirty years ago a bag of guano that contained 22 per cent of ammonia. And farmers could then buy guano guaranteed by the dealers (not by the agents of the Peruvian Government), to contain 16 per cent of ammonia, and 10 per cent of phosphoric acid. Price, £9 5s. per ton of 2,240 lbs.—say $40 per ton of 2,000 lbs.
The average composition of thirty-two cargoes of guano imported into England in 1849 was as follows:
At the present valuation, adopted by the Agents of the Peruvian guano in New York, and estimating that 5 per cent of the phosphoric acid was soluble, and 4 per cent reverted, and that there was 2 lbs. of potash in the alkaline salts, this guano would be worth:
Selling price per ton of 2,000 lbs.
Ichaboe guano, which was largely imported into England in 1844-5, and used extensively as a manure for turnips, contained, on the average, 7½ per cent of ammonia, and 14 per cent of phosphoric acid. Its value at the present rates we may estimate as follows:
Soluble Phosphoric acid, 4 per cent
Reverted Phosphoric acid, 10 per cent
Selling price per ton of 2,000 lbs.