It may be presumed, that, while these figures are notabsolutely, they arerelatively, correct. In other words, we may conclude, that red-clover leaves more nitrogen, phosphoric acid, and potash, in the roots and stubble per acre, than any other of the crops named.
The gross amount of dry substance in the roots, and the gross amount of ash per acre, are considerably exaggerated, owing to the evidently large quantity of dirt attached to the roots and stubble. For instance, the gross amount of ash in Lucern is given as 1,201.6 lbs. per acre; while the total amount of lime, magnesia, potash, soda, sulphuric and phosphoric acids, is only 342.2 lbs. per acre, leaving 859.4 lbs. as sand, clay, iron, etc. Of the 1,919.9 lbs. of ash in the acre of clover-roots and stubble, there are 1,429.4 lbs. of sand, clay, etc. But even after deducting this amount of impurities from a gross total of dry matter per acre, we still have 7,492.2 lbs. of dry roots and stubble per acre, or nearly 3¼ tons ofdryroots per acre. This is a very large quantity. It is as much dry matter as is contained in 13 tons of ordinary farm-yard, or stable-manure. And these 3¼ tons of dry clover-roots contain 191½ lbs. of nitrogen, which is as much as is contained in 19 tons of ordinary stable-manure. The clover-roots also contain 74¾ lbs. of phosphoric acid per acre, or as much as is contained in from 500 to 600 lbs. of No. 1 rectified Peruvian guano.
“But the phosphoric acid,” said the Doctor, “is not soluble in the roots.” True, but it was soluble when the roots gathered it up out of the soil.
“These figures,” said the Deacon, “have a very pleasant look. Those of us who have nearly one-quarter of our land in clover every year, ought to be making our farms very rich.”
“It would seem, at any rate,” said I, “that those of us who have good, clean, well-drained, and well-worked land, that is now producing a good growth of clover, may reasonably expect a fair crop of wheat, barley, oats, corn, or potatoes, when we break it up and plow under all the roots, which are equal to 13 or 19 tons of stable-manure per acre. Whether we can or can not depend on these figures, one thing is clearly proven, both by the chemist and the farmer, that a good clover-sod, on well-worked soil, is a good preparation for corn and potatoes.”
Probably nine-tenths of all the wheat grown in Western New York, or the “Genesee country,” from the time the land was first cleared until 1870, was raised without any manure being directly applied to the land for this crop. Tillage and clover were what the farmers depended on. There certainly has been no systematic manuring. The manure made during the winter, was drawn out in the spring, and plowed under for corn. Any manure made during the summer, in the yards, was, by the best farmers, scraped up andspread on portions of the land sown, or to be sown, with wheat. Even so good a farmer and wheat-grower as John Johnston, rarely used manure, (except lime, and latterly, a little guano), directly for wheat. Clover and summer-fallowing were for many years the dependence of the Western New York wheat-growers.
“One of the oldest and most experienced millers of Western New York,” remarked the Doctor, “once told me that ‘ever since our farmers began tomanure their land, the wheat-crop had deteriorated, not only in the yield per acre, but in the quality and quantity of the flour obtained from it.’ It seemed a strange remark to make; but when he explained that the farmers had given up summer-fallowing and plowing in clover, and now sow spring crops, to be followed by winter wheat with an occasional dressing of poor manure, it is easy to see how it may be true.”
“Yes,” said I, “it is not themanurethat hurts the wheat, but the growth of spring crops and weeds that rob the soil of far more plant-food than the poor, strawy manure can supply. We do not now, really, furnish the wheat-crop as much manure or plant-food as we formerly did when little or no manure was used, and when we depended on summer-fallowing and plowing in clover.”
We must either give up the practice of sowing a spring crop, before wheat, or we must make more and richer manure, or we must plow in more clover. The rotation, which many of us now adopt—corn, barley, wheat—is profitable, provided we can make our land rich enough to produce 75 bushels of shelled corn, 50 bushels of barley, and 35 bushels of wheat, per acre, in three years.
This can be done, but we shall either require a number of acres of rich low land, or irrigated meadow, the produce of which will make manure for the upland, or we shall have to purchase oil-cake, bran, malt-combs, or refuse beans, to feed out with our straw and clover-hay, or we must purchase artificial manures. Unless this is done, we must summer-fallow more, on the heavier clay soils, sow less oats and barley; or we must, on the lighter soils, raise and plow under more clover, or feed it out on the farm, being careful to save and apply the manure.
“Better do both,” said the Doctor.
“How?” asked the Deacon.
“You had better make all the manure you can,” continued the Doctor, “and buy artificial manures besides.”
“The Doctor is right,” said I, “and in point of fact, our best farmers are doing this very thing. They are making more manure and buying more manure than ever before; or, to state the matter correctly, they are buying artificial manures; and these increase thecrops, and the extra quantity of straw, corn, and clover, so obtained, enables them to make more manure. They get cheated sometimes in their purchases; but, on the whole, the movement is a good one, and will result in a higher and better system of farming.”
I am amused at the interest and enthusiasm manifested by some of our farmers who have used artificial manures for a year or two. They seem to regard me as a sad old fogy, because I am now depending almost entirely on the manures made on the farm. Years ago, I was laughed at because I used guano and superphosphate. It was only yesterday, that a young farmer, who is the local agent of this neighborhood, for a manure manufacturer, remarked to me, “You have never used superphosphate. We sowed it on our wheat last year, and could see to the very drill mark how far it went. I would like to take your order for a ton. I am sure it would pay.”
“We are making manure cheaper than you can sell it to me,” I replied, “and besides, I do not think superphosphate is a good manure for wheat.” —“Oh,” he exclaimed, “you would not say so if you had ever used it.” —“Why, my dear sir,” said I, “I made tons of superphosphate, and used large quantities of guano before you were born; and if you will come into the house, I will show you a silver goblet I got for a prize essay on the use of superphosphate of lime, that I wrote more than a quarter of a century ago. I sent to New York for two tons of guano, and published the result of its use on this farm, before you were out of your cradle. And I had a ton or more of superphosphate made for me in 1856, and some before that. I have also used on this farm, many tons of superphosphate and other artificial manures from different manufacturers, and one year I used 15 tons of bone-dust.”
With ready tact, he turned the tables on me by saying: “Now I can understand why your land is improving. It is because you have used superphosphate and bone-dust. Order a few tons.”
By employing agents of this kind, the manufacturers have succeeded in selling the farmers of Western New York thousands of tons of superphosphate. Some farmers think it pays, and some that it does not. We are more likely to hear of the successes than of failures. Still there can be no doubt that superphosphate has, in many instances, proved a valuable and profitable manure for wheat in Western New York.
From 200 to 300 lbs. are used per acre, and the evidence seems to show that it is far better todrill in the manure with the seedthan to sow it broadcast.
My own opinion is, that these superphosphates are not the mosteconomical artificial manures that could be used for wheat. They contain too little nitrogen. Peruvian guano containing nitrogen equal to 10 per cent of ammonia, would be, I think, a much more effective and profitable manure. But before we discuss this question, it will be necessary to study the results of actual experiments in the use of various fertilizers for wheat.
I hardly know how to commence an account of the wonderful experiments made at Rothamsted, England, by John Bennett Lawes, Esq., and Dr. Joseph H. Gilbert. Mr. Lawes’ first systematic experiment on wheat, commenced in the autumn of 1843. A field of 14 acres of rather heavy clay soil, resting on chalk, was selected for the purpose. Nineteen plots were accurately measured and staked off. The plots ran the long way of the field, and up a slight ascent. On each side of the field, alongside the plots, there was some land not included, the first year, in the experiment proper. This land was either left without manure, or a mixture of the manures used in the experiments was sown on it.
I have heard it said that Mr. Lawes, at this time, was a believer in what was called “Liebig’s Mineral Manure Theory.” Liebig had said that “The crops on a field, diminish or increase in exact proportion to the diminution or increase of the mineral substances conveyed to it in manure.” And enthusiastic gentlemen have been known to tell farmers who were engaged in drawing out farm-yard manure to their land, that they were wasting their strength; all they needed was the mineral elements of the manure. “And you might,” they said, “burn your manure, and sow the ashes, and thus save much time and labor. The ashes will do just as much good as the manure itself.”
Whether Mr. Lawes did, or did not entertain such an opinion, I do not know. It looks as though the experiments the first year or two, were made with the expectation that mineral manures, or the ashes of plants, were what the wheat needed.
The following table gives the kind and quantities of manures used per acre, and the yield of wheat per acre, as carefully cleaned for market. Also the total weight of grain per acre, and the weight of straw and chaff per acre.
The following eight tables are shown in “thumbnail” form. The full-width versions can be viewedbelow.
TABLE 1.—MANURES AND PRODUCE; 1ST SEASON, 1843-4. MANURES AND SEED (OLD RED LAMMAS) SOWN AUTUMN 1843.
FMFarmyard Manure.
FMAFarmyard Manure Ashes.1
SiPSilicate of Potass.2
PhPPhosphate of Potass.3
PhSPhosphate of Soda.3
PhMPhosphate of Magnesia.3
SPLSuperphosphate of Lime.3
SAmSulphate of Ammonia.
RCRape Cake.
Wt/Bu.Weight per Bushel.
OCOffal Corn.5
CCorn.
TCTotal Corn.
S&CStraw and Chaff.
TPTotal Produce.
TPTotal Produce (Corn and Straw).
C100Corn to 100 Straw.
1. The farmyard dung was burnt slowly in a heap in the open air to an imperfect or coaly ash, and 32 cwts. of ash represent 14 tons of dung.
2. The silicate of potass was manufactured at a glass-house, by fusing equal parts of pearl-ash and sand. The product was a transparent glass, slightly deliquescent in the air, which was ground to a powder under edge-stones.
3. The manures termed superphosphate of lime, phosphate of potass, phosphate of soda, and phosphate of magnesia, were made by acting upon bone-ash by means of sulphuric acid in the first instance, and in the case-of the alkali salts and the magnesian one neutralizing the compound thus obtained by means of cheap preparations of the respective bases. For the superphosphate of lime, the proportions were 5 parts bone-ash, 3 parts water, and 3 parts sulphuric acid of sp. gr. 1.84; and for the phosphates of potass, soda, and magnesia, they were 4 parts bone-ash, water as needed, 3 parts sulphuric acid of sp. gr. 1.84, and equivalent amounts, respectively, of pearl-ash, soda-ash, or a mixture of 1 part medicinal carbonate of magnesia, and 4 parts magnesian limestone. The mixtures, of course, all lost weight considerably by the evolution of water and carbonic acid.
4. Made with unburnt bones.
5. In this first season, neither the weight nor the measure of the offal corn was recorded separately; and in former papers, the bushels and pecks of total corn (including offal) have erroneously been given as dressed corn. To bring the records more in conformity with those relating to the other years, 5 per cent, by weight, has been deducted from the total corn previously stated as dressed corn, and is recorded as offal corn; this being about the probable proportion, judging from the character of the season, the bulk of the crop, and the weight per bushel of the dressed corn. Although not strictly correct, the statements of dressed corn, as amended in this somewhat arbitrary way, will approximate more nearly to the truth, and be more comparable with those relating to other seasons, than those hitherto recorded.
These were the results of the harvest of 1844. The first year of these since celebrated experiments.
If Mr. Lawes expected that the crops would be in proportion to the minerals supplied in the manure, he must have been greatly disappointed. The plot without manure of any kind, gave 15 bushels of wheat per acre; 700 lbs. of superphosphate of lime, made from burnt bones, produced only 38 lbs. or about half a bushel more grain per acre, and 4 lbs.lessstraw than was obtained without manure. 640 lbs. of superphosphate, and 65 lbs. of commercial sulphate of ammonia (equal to about 14 lbs. of ammonia), gave a little over 19½ bushels of dressed wheat per acre. As compared with the plot having 700 lbs. of superphosphate per acre, this 14 lbs. of available ammonia per acre, or, say 11½ lbs. nitrogen, gave an increase of 324 lbs. of grain, and 252 lbs. of straw, or a total increase of 576 lbs. of grain and straw.
On plot No. 19, 81 lbs. of sulphate ammonia, with minerals, produces 24¼ bushels per acre. This yield is clearly due to the ammonia.
The rape-cake contains about 5 per cent of nitrogen, and is also rich in minerals andcarbonaceous matter. It gives an increase, but not as large in proportion to the nitrogen furnished, as the sulphate of ammonia. And the same remarks apply to the 14 tons of farm-yard manure.
We should have expected a greater increase from such a liberal dressing of barn-yard manure. I think the explanation is this:The manure had not been piled. It was probably taken out fresh from the yard (this, at any rate, was the case when I was at Rothamsted), and plowed under late in the season. And on this heavy land, manure will lie buried in the soil for months, or, if undisturbed, for years, without decomposition. In other words, while this 14 tons of barn-yard manure, contained at least 150 lbs. of nitrogen, and a large quantity of minerals and carbonaceous matter, it did not produce a bushel per acre more than a manure containing less than 12 lbs. of nitrogen. And on plot 19, a manure containing less than 15 lbs. of available nitrogen, produced nearly 4 bushels per acre more wheat than the barn-yard manure containing at leastten timesas much nitrogen.
There can be but one explanation of this fact. The nitrogen in the manure lay dormant in this heavy soil. Had it been a light sandy soil, it would have decomposed more rapidly and produced a better effect.
As we have before stated, John Johnston finds, on his clay-land, a far greater effect from manure spread on the surface, where it decomposes rapidly, than when the manure is plowed under.
The Deacon was looking at the figures in the table, and not paying much attention to our talk. “What could a man be thinking about,” he said, “to burn 14 tons of good manure! It was a great waste, and I am glad the ashes did no sort of good.”
After the wheat was harvested in 1844, the land was immediately plowed, harrowed, etc.; and in a few weeks was plowed again and sown to wheat, the different plots being kept separate, as before.
The following table shows the manures used this second year, and the yield per acre:
TABLE II.—MANURES AND PRODUCE; 2ND SEASON, 1845. MANURES AND SEED (OLD RED LAMMAS) SOWN MARCH 1845.
FMFarmyard Manure.
SiPSilicate of Potass.1
PhPPhosphate of Potass.2
SPLSuperphosphate of Lime.2
B-ABone-ash.
MAcMuriatic Acid.
GGuano.
SAmSulphate of Ammonia.
MAmMuriate of Ammonia.
CAmCarbonate of Ammonia.
RCRape Cake.
TTapioca.
Wt/Bu.Weight per Bushel.
OCOffal Corn.5
CCorn.
TCTotal Corn.
S&CStraw and Chaff.
TP/C&STotal Produce (Corn and Straw).
TPTotal Produce.
OC/100Offal Corn to 100 Dressed.
C100Corn to 100 Straw.
Mixture of the residue of most of the other manures.
1. The silicate of potass was manufactured at a glass-house, by fusing equal parts of pearl-ash and sand. The product was a transparent glass, slightly deliquescent in the air; it was ground to powder under edge-stones.
2. The manures termed superphosphate of lime and phosphate of potass, were made by acting upon bone-ash by means of sulphuric acid, and in the case of the potass salt neutralizing the compound thus obtained, by means of pearl-ash. For thesuperphosphateof lime, the proportions were, 5 parts bone-ash, 3 parts water, and 3 parts sulphuric acid of sp. gr. 1.84; and for the phosphate of potass, 4 parts bone ash, water as needed, 3 parts sulphuric acid of sp. gr. 1.84; and an equivalent amount of pearl-ash. The mixtures, of course, lost weight considerably by the evolution of water and carbonic acid.
3. The medicinal carbonate of ammonia; it was dissolved in water and top-dressed.
4. Plot 5, was 2 lands wide (in after years, respectively, 5aand 5b); 51consisting of 2 alternate one-fourth lengths across both lands, and 52of the 2 remaining one-fourth lengths.
5. Top-dressed at once.
6. Top-dressed at 4 intervals.
7. Peruvian.
8. Ichaboe.
The season of 1845 was more favorable for wheat, than that of 1844, and the crops on all the plots were better. On plot No. 3, which had no manure last year, or this, the yield is 23 bushels per acre, against 15 bushels last year.
Last year, the 14 tons of barn-yard manure gave anincreaseof only 5¼ bushels per acre. This year it gives an increase of nearly 9 bushels per acre.
“Do you mean,” said the Deacon, “that this plot, No. 2, had 14 tons of manure in 1844, and 14 tons of manure again in 1845?”
“Precisely that, Deacon,” said I, “and this same plot has received this amount of manure every year since, up to the present time—for these same experiments are still continued from year to year at Rothamsted.”
“It is poor farming,” said the Deacon, “and I should think the land would get too rich to grow wheat.”
“It is not so,” said I, “and the fact is an interesting one, and teaches a most important lesson, of which, more hereafter.”
Plot 5, last year, received 700 lbs. of superphosphate per acre. This year, this plot was divided; one half was left without manure, and the other dressed with 252 lbs. of pure carbonate of ammonia per acre. The half without manure, (5a), did not produce quite as much grain and straw as the plot which had received no manure for two years in succession. But the wheat was of better quality, weighing 1 lb. more per bushel than the other. Still it is sufficiently evident that superphosphate of lime did no good so far as increasing the growth was concerned, either the first year it was applied, or the year following.
The carbonate of ammonia was dissolved in water and sprinkled over the growing wheat at three different times during the spring. You see this manure, which contains nomineralmatter at all, gives an increase of nearly 4 bushels of grain per acre, and an increase of 887 lbs. of straw.
“Wait a moment,” said the Deacon, “is not 887 lbs. of straw to4 bushels of grain an unusually large proportion of straw to grain? I have heard you say that 100 lbs. of straw to each bushel of wheat is about the average. And according to this experiment, the carbonate of ammonia produced over 200 lbs. of straw to a bushel of grain. How do you account for this.”
“It is a general rule,” said I, “that the heavier the crop, the greater is the proportion of straw to grain. On the no-manure plot, we have, this year, 118 lbs. of straw to a bushel of dressed grain. Taking this as the standard, you will find that theincreasefrom manures is proportionally greater in straw than in grain. Thus in the increase of barn-yard manure, this year, we have about 133 lbs. of straw to a bushel of grain. I do not believe there is any manure that will give us a large crop of grain without a still larger crop of straw. There is considerable difference, in this respect, between different varieties of wheat. Still, I like to see a good growth of straw.”
“It is curious,” said the Doctor, “that 3 cwt. of ammonia-salts alone on plots 9 and 10 should produce as much wheat as was obtained from plot 2, where 14 tons of barn-yard manure had been applied two years in succession. I notice that on one plot, the ammonia-salts were applied at once, in the spring, while on the other plot they were sown at four different times—and that the former gave the best results.”
The only conclusion to be drawn from this, is, that it is desirable to apply the manureearlyin the spring—or better still, in the autumn.
“You are a great advocate of Peruvian guano,” said the Deacon, “and yet 3 cwt. of Peruvian guano on Plot 13, only produced an increase of two bushels and 643 lbs. of straw per acre. The guano at $60 per ton, would cost $9.00 per acre. This will not pay.”
This is an unusually small increase. The reason, probably, is to be found in the fact that the manure and seed were not sown until March, instead of in the autumn. The salts of ammonia are quite soluble and act quickly; while the Peruvian guano has to decompose in the soil, and consequently needs to be applied earlier, especially on clay land.
“I do not want you,” said the Deacon, “to dodge the question why an application of 14 tons of farmyard-manure per acre, every year for over thirty years, does not make the land too rich for wheat.”
“Possibly,” said I, “on light, sandy soil, such an annual dressing of manurewouldin the course of a few years make the land toorich for wheat. But on a clayey soil, such is evidently not the case. And the fact is a very important one. When we apply manure, our object should be to make it as available as possible. Nature preserves or conserves the food of plants. The object of agriculture is to use the food of plants for our own advantage.”
“Please be a little more definite,” said the Deacon, “for I must confess I do not quite see the significance of your remarks.”
“What he means,” said the Doctor, “is this: If you put a quantity of soluble and available manure on land, and do not sow any crop, the manure will not be wasted. The soil will retain it. It will change it from a soluble into a comparatively insoluble form. Had a crop been sown the first year, the manure would do far more good than it will the next year, and yet it may be that none of the manure is lost. It is merely locked up in the soil in such a form as will prevent it from running to waste. If it was not for this principle, our lands would have been long ago exhausted of all their available plant-food.”
“I think I understand,” said the Deacon; “but if what you say is true, it upsets many of our old notions. We have thought it desirable to plow under manure, in order to prevent the ammonia from escaping. You claim, I believe, that there is little danger of any loss from spreading manure on the surface, and I suppose you would have us conclude that we make a mistake in plowing it under, as the soil renders it insoluble.”
“It depends a good deal,” said I, “on the character of the soil. A light, sandy soil will not preserve manure like a clay soil. But it is undoubtedly true that our aim in all cases should be to apply manure in such a form and to such a crop as will give us the greatestimmediatebenefit. Plowing under fresh manure every year for wheat is evidently not the best way to get the greatest benefit from it. But this is not the place to discuss this matter. Let us look at the result of Mr. Lawes’ experiments on wheat the third year:”
TABLE III.—MANURES AND PRODUCE; 3RD SEASON, 1845-6. MANURES AND SEED (OLD RED LAMMAS), SOWN AUTUMN, 1845.
FMFarmyard Manure.
A3WAsh from 3 loads (3,888 lbs.) Wheat-straw.
LWMLiebig’s Wheat-manure.
PGPeruvian Guano.
SiPSilicate of Potass.1
P-APearl-ash.
S-ASoda-ash.
MLSMagnesian Lime-stone.
SPLSuperphosphate of Lime.
B-ABone-ash.
SAcSulphuric Acid (Sp. gr. 1-7.)
MAcMuriatic Acid.
SAmSulphate of Ammonia.
MAmMuriate of Ammonia.
RCRape-Cake.
Wt/Bu.Weight per Bushel.
OCOffal Corn.
TCTotal Corn.
S&CStraw and Chaff.
TPTotal Produce (Corn and Straw).
CCorn.
TPTotal Produce.
OCDOffal Corn to 100 Dressed.
C100Corn to 100 Straw.
1. Top-dressed in the Spring.
This year, the seed and manures were sown in the autumn. And I want the Deacon to look at plot 0. 3 cwt. of Peruvian guano here gives an increase of 10½ bushels of wheat, and 1,948 lbs. of straw per acre. This will paywell, even on the wheat alone. But in addition to this, we may expect, in our ordinary rotation of crops, a far better crop of clover where the guano was used.
In regard to some of the results this year, Messrs. Lawes and Gilbert have the following concise and interesting remarks:
“At this third experimental harvest, we have on the continuously unmanured plot, namely, No. 3, not quite 18 bushels of dressed corn, as the normal produce of the season; and by its side we have on plot 10b—comprising one-half of the plot 10 of the previous years, and so highly manured by ammoniacal salts in 1845, but now unmanured—rather more than 17½ bushels. The near approach, again, to identity of result from the two unmanured plots, at once gives confidence in the accuracy of the experiments, and shows us how effectually the preceding crop had, in a practical point of view, reduced the plots, previously so differently circumstanced both as to manure and produce, to something like an uniform standard as regards their grain-producing qualities.
“Plot 2 has, as before, 14 tons of farm-yard manure, and the produce is 27¼ bushels, or between 9 and 10 bushels more than without manure of any kind.
“On plot 10a, which in the previous year gave by ammoniacal salts alone, a produce equal to that of the farm-yard manure, we have again a similar result: for two cwts. of sulphate of ammonia has now given 1,850 lbs. of total corn, instead of 1,826 lbs., which is the produce on plot 2. The straw of the latter, is, however, slightly heavier than that by the ammoniacal salt.
“Again, plot 5a, which was in the previous seasonunmanured, was now subdivided: on one-half of it (namely, 5a1) we have the ashes of wheat-straw alone, by which there is an increase of rather more than one bushel per acre of dressed corn; on the other half (or 5a2) we have, besides the straw-ashes, two cwts. of sulphate of ammonia put on as a top-dressing: two cwts. of sulphate of ammonia have, in this case, only increased the produce beyond that of 5a1by 7⅞ bushels of corn and 768 lbs. of straw, instead of by 9¾ bushels of corn and 789 lbs. of straw, which was the increase obtained by the same amount of ammoniacal salt on 10a, as compared with 10b.
“It will be observed, however, that in the former case the ammoniacal salts were top-dressed, but in the latter they were drilled at the time of sowing the seed; and it will be remembered that in1845 the result was betteras to cornon plot 9, where the salts were sown earlier, than on plot 10, where the top-dressing extended far into the spring. We have had several direct instances of this kind in our experience, and we would give it as a suggestion, in most cases applicable, that manures for wheat, and especially ammoniacal ones, should be applied before or at the time the seed is sown; for, although the apparent luxuriance of the crop is greater, and the produce of straw really heavier, by spring rather than autumn sowings of Peruvian guano and other ammoniacal manures, yet we believe that that of thecornwill not be increased in an equivalent degree. Indeed, the success of the crop undoubtedly depends very materially on the progress of the underground growth during the winter months; and this again, other things being equal, upon the quantity of available nitrogenous constituents within the soil, without a liberal provision of which, the range of the fibrous feeders of the plant will not be such, as to take up the minerals which the soil is competent to supply, and in such quantity as will be required during the after progress of the plant for its healthy and favorable growth.”
These remarks are very suggestive and deserve special attention.
“The next result to be noticed,” continue Messrs. Lawes and Gilbert, “is that obtained on plot 6, now also divided into two equal portions designated respectively 6aand 6b. Plot No. 6 had for the crop of 1844, superphosphate of lime and the phosphate of magnesia manure, and for that of 1845, superphosphate of lime, rape-cake, and ammoniacal salts. For this, the third season, it was devoted to the trial of the wheat-manure manufactured under the sanction of Professor Liebig, and patented in this country.
“Upon plots 6a, four cwts. per acre of the patent wheat-manure were used, which gave 20¼ bushels, or rather more than two bushels beyond the produce of the unmanured plot; but as the manure contained, besides the minerals peculiar to it, some nitrogenous compounds, giving off a very perceptible odor of ammonia, some, at least, of the increase would be due to that substance. On plot 6b, however, the further addition of one cwt. each of sulphate and muriate of ammonia to this so-called ‘Mineral Manure,’ gives a produce of 29¼ bushels. In other words, the addition of ammoniacal salt, to Liebig’s mineral manure has increased the produce by very nearly 9 bushels per acre beyond that of the mineral manure alone, whilst the increase obtained over the unmanured plot, by 14 tons of farm-yard manure, was only 9¼ bushels!
The following table gives the results of the experiments thefourthyear, 1846-7.
TABLE IV.—MANURES AND PRODUCE; 4TH SEASON, 1846-7. MANURES AND SEED (OLD RED LAMMAS), SOWN END OF OCTOBER, 1846.
FMFarm-yard Manure.
PGPeruvian Guano.
SPLSuperphosphate of Lime.
B-ABone-ash.
SAcSulphuric Acid (Sp. gr. 1-7.)
MAcMuriatic Acid.
SAmSulphate of Ammonia.
MAmMuriate of Ammonia.
RRice.
Wt/Bu.Weight per Bushel.
OCOffal Corn.
TCTotal Corn.
S&CStraw and Chaff.
TP/C&STotal Produce (Corn and Straw.)
CCorn.
TPTotal Produce.
OCDOffal Corn to 100 Dressed.
C100Corn to 100 Straw.