Talks on Manures
by Joseph Harris
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"That is a remarkable fact," said the Deacon, "as I understand nitrogen is the great thing needed by wheat, and yet the roots alone of the clover, contain twice as much nitrogen as an average crop of wheat. Go on Charley, it is quite interesting."

"The soil," continues Dr. Voelcker, "which had been separated from the roots, was passed through a sieve to deprive it of any stones it might contain. It was then partially dried, and the nitrogen in it determined in the usual manner, by combustion with soda-lime, when it yielded .313 per cent of nitrogen, equal to .38 of ammonia, in one combustion; and .373 per cent of nitrogen, equal to .46 of ammonia, in a second determination.

"That the reader may have some idea of the character of this soil, it may be stated, that it was further submitted to a general analysis, according to which, it was found to have the following composition:

General Composition of Soil, No. 1. (Good Clover).

Moisture 18.73 Organic matter[A] 9.72 Oxide of iron and alumina 13.24 Carbonate of lime 8.82 Magnesia, alkalies, etc. 1.72 Insoluble silicious matter, (chiefly clay) 47.77 ———- 100.00 ======= [A] Containing nitrogen .313 Equal to ammonia .380

"The second square yard from the brow of the hill, where the clover was bad, produced 13 ounces of air-dry, and partially clean roots, or 1.75 tons per acre. On analysis, they were found to have the following composition:

Clover-Roots, No. 2. (Bad Clover).

Water 55.732 Organic matter[A] 39.408 Mineral matter, (ash) 4.860 ———- 100.000 ======= [A] Containing nitrogen .792 Equal to ammonia .901

"The roots on the spot where the clover was very bad, yielded only 31 lbs. of nitrogen per acre, or scarcely one-third of the quantity which was obtained from the roots where the clover was good.

"The soil from the second square yard, on analysis, was found, when freed from stones by sifting, to contain in 100 parts:

Composition of Soil, No. 2. (Bad Clover).

Water 17.24 Organic matter[A] 9.64 Oxide of iron and alumina 11.89 Carbonate of lime 14.50 Magnesia, alkalies, etc. 1.53 Insoluble silicious matter 45.20 ———- 100.00 ======= 2d determination. [A] Containing nitrogen .306 .380 Equal to ammonia .370 .470

"Both portions of the clover-soil thus contained about the same percentage of organic matter, and yielded nearly the same amount of nitrogen.

"In addition, however, to the nitrogen in the clover-roots, a good deal of nitrogen, in the shape of root-fibres, decayed leaves, and similar organic matters, was disseminated throughout the fine soil in which it occurred, and from which it could not be separated; but unfortunately, I neglected to weigh the soil from a square yard, and am, therefore, unable to state how much nitrogen per acre was present in the shape of small root-fibres and other organic matters.

"Before mentioning the details of the experiments made in the next season, I will here give the composition of the ash of the partially cleaned clover-roots:

Composition Of Ash Of Clover-Roots, (Partially Cleaned).

Oxide of iron and alumina 11.73 Lime 18.49 Magnesia 3.03 Potash 6.88 Soda 1.93 Phosphoric acid 3.61 Sulphuric acid 2.24 Soluble silica 19.01 Insoluble silicious matter 24.83 Carbonic acid, chlorine, and loss 8.25 ——— 100.00 ======

"This ash was obtained from clover-roots, which yielded, when perfectly dry, in round numbers, eight per cent of ash. Clover-roots, washed quite clean, and separated from all soil, yield about five per cent of ash; but it is extremely difficult to clean a large quantity of fibrous roots from all dirt, and the preceding analysis distinctly shows, that the ash of the clover-roots, analyzed by me, was mechanically mixed with a good deal of fine soil, for oxide of iron, and alumina, and insoluble silicious matter in any quantity, are not normal constituents of plant-ashes. Making allowance for soil contamination, the ash of clover-roots, it will be noticed, contains much lime and potash, as well as an appreciable amount of phosphoric and sulphuric acid. On the decay of the clover-roots, these and other mineral fertilizing matters are left in the surface-soil in a readily available condition, and in considerable proportions, when the clover stands well. Although a crop of clover removes much mineral matter from the soil, it must be borne in mind, that its roots extract from the land, soluble mineral fertilizing matters, which, on the decay of the roots, remain in the land in a prepared and more readily available form, than that in which they originally occur. The benefits arising to wheat, from the growth of clover, may thus be due partly to this preparation and concentration of mineral food in the surface-soil.

"The clover on the hillside field, on the whole, turned out a very good crop; and, as the plant stood the winter well, and this field was left another season in clover, without being plowed up, I availed myself of the opportunity of making, during the following season, a number of experiments similar to those of the preceding year. This time, however, I selected for examination, a square yard of soil, from a spot on the brow of the hill, where the clover was thin, and the soil itself stony at a depth of four inches; and another plot of one square yard at the bottom of the hill, from a place where the clover was stronger than that on the brow of the hill, and the soil at a depth of six inches contained no large stones.


"The roots in a square yard, six inches deep, when picked out by hand, and cleaned as much as possible, weighed, in their natural state, 2 lbs. 11 oz.; and when dried on the top of a water-bath, for the purpose of getting them brittle and fit for reduction into fine powder, 1 lb. 12 oz. 31 grains. In this state they were submitted as before to analysis, when they yielded in 100 parts:

Composition Of Clover-Roots, No. 1, (From Brow Of Hill).

Moisture 4.34 Organic matter[A] 26.53 Mineral matter 69.13 ———- 100.00 ======= [A] Containing nitrogen .816 Equal to ammonia .991

"According to these data, an acre of land will yield three tons 12 cwts. of nearly dry clover-roots, and in this quantity there will be about 66 lbs. of nitrogen. The whole of the soil from which the roots have been picked out, was passed through a half-inch sieve. The stones left in the sieve weighed 141 lbs.; the soil which passed through weighing 218 lbs.

"The soil was next dried by artificial heat, when the 218 lbs. became reduced to 185.487 lbs.

"In this partially dried state it contained:

Moisture 4.21 Organic matter[A] 9.78 Mineral matter[B] 86.01 ———- 100.00 ======= [A] Containing nitrogen .391 Equal to ammonia .475 [B] Including phosphoric acid .264

"I also determined the phosphoric acid in the ash of the clover-roots. Calculated for the roots in a nearly dry state, the phosphoric acid amounts to .287 per cent.

"An acre of soil, according to the data, furnished by the six inches on the spot where the clover was thin, produced the following quantity of nitrogen:

Ton. Cwts. Lbs.

In the fine soil 1 11 33 In the clover-roots 0 0 66 — — — Total quantity of nitrogen per acre 1 11 99 == == ==

"The organic matter in an acre of this soil, which can not be picked out by hand, it will be seen, contains an enormous quantity of nitrogen; and although, probably, the greater part of the roots and other remains from the clover-crop may not be decomposed so thoroughly as to yield nitrogenous food to the succeeding wheat-crop, it can scarcely be doubted that a considerable quantity of nitrogen will become available by the time the wheat is sown, and that one of the chief reasons why clover benefits the succeeding wheat-crop, is to be found in the abundant supply of available nitrogenous food furnished by the decaying clover-roots and leaves.


"A square yard of the soil from the bottom of the hill, where the clover was stronger than on the brow of the hill, produced 2 lbs. 8 oz. of fresh clover-roots; or 1 lb. 11 oz. 47 grains of partially dried roots; 61 lbs. 9 oz. of limestones, and 239.96 lbs. of nearly dry soil.

"The partially dried roots contained:

Moisture 5.06 Organic matter[A] 31.94 Mineral matter 63.00 ———- 100.00 ======= [A] Containing nitrogen .804

"An acre of this soil, six inches deep, produced 3 tons, 7 cwts. 65 lbs. of clover-roots, containing 61 lbs. of nitrogen; that is, there was very nearly the same quantity of roots and nitrogen in them, as that furnished in the soil from the brow of the hill.

"The roots, moreover, yielded .365 per cent of phosphoric acid; or, calculated per acre, 27 lbs.

"In the partially dried soil, I found:

Moisture 4.70 Organic matter[A] 10.87 Mineral matter[B] 84.43 ———- 100.00 ======= [A] Containing nitrogen .405 Equal to ammonia .491 [B] Including phosphoric acid .321

"According to these determinations, an acre of soil from the bottom of the hill, contains:

Tons Cwts. Lbs. Nitrogen in the organic matter of the soil 2 2 0 Nitrogen in clover-roots of the soil 0 0 61 —- —- —- Total amount of nitrogen per acre 2 2 61 === === ===

"Compared with the amount of nitrogen in the soil from the brow of the hill, about 11 cwt. more nitrogen was obtained in the soil and roots from the bottom of the hill, where the clover was more luxuriant.

"The increased amount of nitrogen occurred in fine root-fibres and other organic matters of the soil, and not in the coarser bits of roots which were picked out by the hand. It may be assumed that the finer particles of organic matter are more readily decomposed than the coarser roots; and as there was a larger amount of nitrogen in this than in the preceding soil, it may be expected that the land at the bottom of the hill, after removal of the clover, was in a better agricultural condition for wheat, than that on the brow of the hill."



"The soils for the next experiments, were kindly supplied to me, in 1866, by Robert Valentine, of Burcott Lodge, who also sent me some notes respecting the growth and yield of clover-hay and seed on this soil.

"Foreign seed, at the rate of 12 lbs. per acre, was sown with a crop of wheat, which yielded five quarters per acre the previous year.

"The first crop of clover was cut down on the 25th of June, 1866, and carried on June 30th. The weather was very warm, from the time of cutting until the clover was carted, the thermometer standing at 80 Fahr. every day. The clover was turned in the swath, on the second day after it was cut; on the fourth day, it was turned over and put into small heaps of about 10 lbs. each; and on the fifth day, these were collected into larger cocks, and then stacked.

"The best part of an 11-acre field, produced nearly three tons of clover-hay, sun-dried, per acre; the whole field yielding on an average, 2-1/2 tons per acre. This result was obtained by weighing the stack three months after the clover was carted. The second crop was cut on the 21st of August, and carried on the 27th, the weight being nearly 30 cwt. of hay per acre. Thus the two cuttings produced just about four tons of clover-hay per acre.

"The 11 acres were divided into two parts. About one-half was mown for hay a second time, and the other part left for seed. The produce of the second half of the 11-acre field, was cut on the 8th of October, and carried on the 10th. It yielded in round numbers, 3 cwt. of clover-seed per acre, the season being very unfavorable for clover-seed. The second crop of clover, mown for hay, was rather too ripe, and just beginning to show seed.

"A square foot of soil, 18 inches deep, was dug from the second portion of the land which produced the clover-hay and clover-seed.


"The upper six inches of soil, one foot square, contained all the main roots of 18 strong plants; the next six inches, only small root fibres, and in the third section, a six-inch slice cut down at a depth of 12 inches from the surface, no distinct fibres could be found. The soil was almost completely saturated with rain when it was dug up on the 13th of September, 1866: Lbs. The upper six inches of soil, one foot square, weighed 60 The second " " " 61 The third " " " 63

"These three portions of one foot of soil, 18 inches deep, were dried nearly completely, and weighed again; when the first six inches weighed 51-1/4 lbs.; the second six inches, 51 lbs. 5 oz.; and the third section, 54 lbs. 2 oz.

"The first six inches contained 3 lbs. of silicious stones, (flints), which were rejected in preparing a sample for analysis; in the two remaining sections there were no large sized stones. The soils were pounded down, and passed through a wire sieve.

"The three layers of soil, dried and reduced to powder, were mixed together, and a prepared average sample, when submitted to analysis, yielded the following results:

Composition of Clover-Soil, 18 Inches Deep, From Part of 11-Acre Field, Twice Mown for Hay.

{Organic matter 5.86 {Oxides of iron 6.83 {Alumina 7.12 {Carbonate of lime 2.13 Soluble in {Magnesia 2.01 hydrochloric acid. {Potash .67 {Soda .08 {Chloride of sodium .02 {Phosphoric acid .18 {Sulphuric acid .17

{Insoluble silicious matter, 74.61. { Consisting of: {Alumina 4.37 {Lime, (in a state of silicate) 4.07 Insoluble in acid {Magnesia .46 {Potash .19 {Soda .23 {Silica 65.29 ——- 99.68 =====

"This soil, it will be seen, contained, in appreciable quantities, not only potash and phosphoric acid, but all the elements of fertility which enter into the composition of good arable land. It may be briefly described as a stiff clay soil, containing a sufficiency of lime, potash, and phosphoric acid, to meet all the requirements of the clover-crop. Originally, rather unproductive, it has been much, improved by deep culture; by being smashed up into rough clods, early in autumn, and by being exposed in this state to the crumbling effects of the air, it now yields good corn and forage crops.

"In separate portions of the three layers of soil, the proportions of nitrogen and phosphoric acid contained in each layer of six inches, were determined and found to be as follows:

Soil dried at 212 deg. Fahr.

1st six 2d six 3d six inches. inches. inches. Percentage of phosphoric acid .249 .134 .172 Nitrogen 1.62 .092 .064 Equal to ammonia .198 .112 .078

"In the upper six inches, as will be seen, the percentage of both phosphoric acid and nitrogen, was larger than in the two following layers, while the proportion of nitrogen in the six inches of surface soil, was much larger than in the next six inches; and in the third section, containing no visible particles of root-fibres, only very little nitrogen occurred.

"In their natural state, the three layers of soil contained:

1st six 2d six 3d six inches. inches. inches. Moisture 17.16 18.24 16.62 Phosphoric acid .198 .109 .143 Nitrogen .134 .075 .053 Equal to ammonia .162 .091 .064 Lbs. Lbs. Lbs. Weight of one foot square of soil 60 61 63

"Calculated per acre, the absolute weight of one acre of this land, six inches deep, weighs:

Lbs. 1st six inches 2,613,600 2d six inches 2,657,160 3d six inches 2,746,280 =========

"No great error, therefore, will be made, if we assume in the subsequent calculations, that six inches of this soil weighs two and one-half millions of pounds per acre.

"An acre of land, according to the preceding determinations, contains:

1st six 2d six 3d six inches, inches, inches, Lbs. Lbs. Lbs. Phosphoric acid 4,950 2,725 3,575 Nitrogen 3,350 1,875 1,325 Equal to ammonia 4,050 2,275 1,600 ===== ===== =====

"The proportion of phosphoric acid in six inches of surface soil, it will be seen, amounted to about two-tenths per cent; a proportion of the whole soil, so small that it may appear insufficient for the production of a good corn-crop. However, when calculated to the acre, we find that six inches of surface soil in an acre of land, actually contain over two tons of phosphoric acid. An average crop of wheat, assumed to be 25 bushels of grain, at 60 lbs. per bushel, and 3,000 lbs. of straw, removes from the land on which it is grown, 20 lbs. of phosphoric acid. The clover-soil analyzed by me, consequently contains an amount of phosphoric acid in a depth of only six inches, which is equal to that present in 247-1/2 average crops of wheat; or supposing that, by good cultivation and in favorable seasons, the average yield of wheat could be doubled, and 50 bushels of grain, at 60 lbs. a bushel, and 6,000 lbs. of straw could be raised, 124 of such heavy wheat-crops would contain no more phosphoric acid than actually occurred in six inches of this clover-soil per acre.

"The mere presence of such an amount of phosphoric acid in a soil, however, by no means proves its sufficiency for the production of so many crops of wheat; for, in the first place, it can not be shown that the whole of the phosphoric acid found by analysis, occurs in the soil in a readily available combination; and, in the second place, it is quite certain that the root-fibres of the wheat-plant can not reach and pick up, so to speak, every particle of phosphoric acid, even supposing it to occur in the soil in a form most conducive to 'ready assimilation by the plant.'

"The calculation is not given in proof of a conclusion which would be manifestly absurd, but simply as an illustration of the enormous quantity in an acre of soil six inches deep, of a constituent forming the smaller proportions of the whole weight of an acre of soil of that limited depth. It shows the existence of a practically unlimited amount of the most important mineral constituents of plants, and clearly points out the propriety of rendering available to plants, the natural resources of the soil in plant-food; to draw, in fact, up the mineral wealth of the soil, by thoroughly working the land, and not leaving it unutilized as so much dead capital."

"Good," said the Deacon, "that is the right doctrine."

"The roots," continues Dr. Voelcker, "from one square foot of soil were cleaned as much as possible, dried completely at 212deg., and in that state weighed 240 grains. An acre consequently contained 1,493-1/2 lbs. of dried clover-roots.

"The clover-roots contained, dried at 212deg. Fahr.,

Organic matter[A] 81.33 Mineral matter,[B] (ash) 18.67 ——— 100.00 ====== [A] Yielding nitrogen 1.635 Equal to ammonia 1.985 [B] Including insoluble silicious matter, (clay and sand) 11.67

"Accordingly the clover-roots in an acre of land furnished 24-1/2 lbs. of nitrogen. We have thus:

Lbs. of nitrogen In the six inches of surface soil 3,350 In large clover-roots 24-1/2 In second six inches of soil 1,875 ————- Total amount of nitrogen in one acre of soil 12 inches deep 5,249-1/2 Equal to ammonia 6,374-1/2 =========

Or in round numbers, two tons six cwt. of nitrogen per acre; an enormous quantity, which must have a powerful influence in encouraging the luxuriant development of the succeeding wheat-crop, although only a fraction of the total amount of nitrogen in the clover remains may become sufficiently decomposed in time to be available to the young wheat-plants.


"Produce 2-1/2 tons of clover-hay, and 3 cwt. of seed per acre.

"This soil was obtained within a distance of five yards from the part of the field where the soil was dug up after the two cuttings of hay. After the seed there was some difficulty in finding a square foot containing the same number of large clover-roots, as that on the field twice mown; however, at last, in the beginning of November, a square foot containing exactly 18 strong roots, was found and dug up to a depth of 18 inches. The soil dug after the seed was much drier than that dug after the two cuttings of hay:

The upper six inches deep, one foot square, weighed 56 lbs. The next " " " 58 " The third " " " 60 " =======

"After drying by exposure to hot air, the three layers of soil weighed:

The upper six inches, one foot square 49-3/4 lbs. The next " " 50-1/2 " The third " " 51-1/4 " ===========

"Equal portions of the dried soil from each six-inch section were mixed together and reduced to a fine powder. An average sample thus prepared, on analysis, was found to have the following composition:

Composition of Clover-Soil Once Mown for Hay, and Afterwards Left for Seed. Dried at 212deg. Fahr.

{ Organic matter 5.34 { Oxides of iron 6.07 { Alumina 4.51 { Carbonate of lime 7.51 Soluble in { Magnesia 1.27 hydrochloric Acid { Potash .52 { Soda .16 { Chloride of sodium .03 { Phosphoric acid .15 { Sulphuric acid .19

{ Insoluble silicious matter, { 73.84. Consisting of: { Alumina 4.14 { Lime (in a state of silicate) 2.69 Insoluble in acid { Magnesia .68 { Potash .24 { Soda .21 { Silica 65.88 ——- 99.59 =====

"The soil, it will be seen, in general character, resembles the preceding sample; it contains a good deal of potash and phosphoric acid, and may be presumed to be well suited to the growth of clover. It contains more carbonate of lime, and is somewhat lighter than the sample from the part of the field twice mown for hay, and may be termed heavy calcareous clay.

"An acre of this land, 18 inches deep, weighed, when very nearly dry:

Lbs. Surface, six inches 2,407,900 Next " 2,444,200 Third " 2,480,500

"Or in round numbers, every six inches of soil weighed per acre 2-1/2 millions of pounds, which agrees tolerably well with the actual weight per acre of the preceding soil.

"The amount of phosphoric acid and nitrogen in each six-inch layer was determined separately, as before, when the following results were obtained: In Dried Soil.

First six Second Third six inches. six inches. inches. Percentage of phosphoric acid .159 .166 .140 Nitrogen .189 .134 .089 Equal to ammonia .229 .162 .108

"An acre, according to these determinations, contains in the three separate sections:

First six Second Third six inches. six inches. inches. lbs. lbs. lbs.

Phosphoric acid 3,975 4,150 3,500 Nitrogen 4,725 3,350 2,225 Equal to ammonia 5,725 4,050 2,700

"Here, again, as might naturally be expected, the proportion of nitrogen is largest in the surface, where all the decaying leaves dropped during the growth of the clover for seed are found, and wherein root-fibres are more abundant than in the lower strata. The first six inches of soil, it will be seen, contained in round numbers, 2-1/2 tons of nitrogen per acre, that is, considerably more than was found in the same section of the soil where the clover was mown twice for hay; showing plainly, that during the ripening of the clover seed, the surface is much enriched by the nitrogenous matter in the dropping leaves of the clover-plant.

"Clover-roots.—The roots from one square foot of this soil, freed as much as possible from adhering soil, were dried at 212deg., and when weighed and reduced to a fine powder, gave, on analysis, the following results:

Organic matter[A] 64.76 Mineral matter[B] 35.24 ———- 100.00 ======= [A] Containing nitrogen 1.702 Equal to ammonia 2.066 [B] Including clay and sand (insoluble silicious matter) 26.04

"A square foot of this soil produced 582 grains of dried clover-roots, consequently an acre yielded 3,622 lbs. of roots, or more than twice the weight of roots obtained from the soil of the same field where the clover was twice mown for hay.

"In round numbers, the 3,622 lbs. of clover-roots from the land mown once, and afterwards left for seed, contained 51-1/2 lbs. of nitrogen.

"The roots from the soil after clover-seed, it will be noticed, were not so clean as the preceding sample, nevertheless, they yielded more nitrogen. In 64.76 of organic matter, we have here 1.702 of nitrogen, whereas, in the case of the roots from the part of the field where the clover was twice mown for hay, we have in 81.33 parts, that is, much more organic matter, and 1.635, or rather less of nitrogen. It is evident, therefore, that the organic matter in the soil after clover-seed, occurs in a more advanced stage of decomposition, than found in the clover-roots from the part of the field twice mown. In the manure, in which the decay of such and similar organic remains proceeds, much of the non-nitrogenous, or carbonaceous matters, of which these remains chiefly, though not entirely, consist, is transformed into gaseous carbonic acid, and what remains behind, becomes richer in nitrogen and mineral matters. A parallel case, showing the dissipation of carbonaceous matter, and the increase in the percentage of nitrogen and mineral matter in what is left behind, is presented to us in fresh and rotten dung; in long or fresh dung, the percentage of organic matter, consisting chiefly of very imperfectly decomposed straw, being larger, and that of nitrogen and mineral matter smaller, than in well-rotted dung.

"The roots from the field after clover-seed, it will be borne in mind, were dug up in November, whilst those obtained from the land twice mown, were dug up in September; the former, therefore, may be expected to be in a more advanced state of decay than the latter, and richer in nitrogen.

"In an acre of soil, after clover-seed, we have:

Lbs. Nitrogen in first six inches of soil 4,725 Nitrogen in roots 51-1/2 Nitrogen in second six inches of soil 3,350 ———- Total amount of nitrogen, per acre, in twelve inches of soil 8,126-1/2 =======

"Equal to ammonia, 9,867 lbs.: or, in round numbers, 3 tons and 12-1/2 cwts. of nitrogen per acre; equal to 4 tons 8 cwts. of ammonia.

"This is a very much larger amount of nitrogen than occurred in the other soil, and shows plainly that the total amount of nitrogen accumulates especially in the surface-soil, when clover is grown for seed; thus explaining intelligibly, as it appears to me, why wheat, as stated by many practical men, succeeds better on land where clover is grown for seed, than where it is mown for hay.

"All the three layers of the soil, after clover-seed, are richer in nitrogen than the same sections of the soil where the clover was twice mown, as will be seen by the following comparative statement of results:

I. II. Clover-Soil twice Clover-Soil once mown mown. and then left for seed. Upper Second Third Upper Next Lowest 6 inches 6 inches 6 inches 6 inches 6 inches 6 inches Percentage of nitrogen in .168 .092 .064 .189 .134 .089 dried soil Equal to ammonia .198 .112 .078 .229 .162 .108

"This difference in the amount of accumulated nitrogen in clover-land, appears still more strikingly on comparing the total amounts of nitrogen per acre in the different sections of the two portions of the 11-acre field.

Percentage of Nitrogen Per Acre.

First six Second Third six inches. six inches. inches. Lbs. Lbs. Lbs. I. In soil, clover twice } mown[A] } 3,350 1,875 1,325 II. In soil, clover once } mown and seeded } afterwards[B] } 4,725 3,350 2,225 ===== ===== ===== Equal to ammonia: [A] I. Clover twice mown } 4,050 2,275 1,600 [B] II. Clover seeded } 5,725 4,050 2,700

Lbs. I. Nitrogen in roots of clover twice mown } 24-1/2 II. Nitrogen in clover, once mown, and grown } for seed afterwards } 51-1/2 I. Weight of dry roots per acre from Soil I } 1,493-1/2 II. Weight of dry roots per acre from Soil II } 3,622 Total amount of nitrogen in 1 acre, 12 inches } deep of Soil I[A] } 5,249-1/4 Total amount of nitrogen in 1 acre, 12 inches } deep of Soil II[B] } 8,126-1/4 Excess of nitrogen in an acre of soil 12 } inches deep, calculated as ammonia in part } of field, mown once and then seeded } 3,592-1/2 ————- [A] Equal to ammonia } 6,374-1/2 [B] Equal to ammonia } 9,867

"It will be seen that not only was the amount of large clover-roots greater in the part where clover was grown for seed, but that likewise the different layers of soil were in every instance richer in nitrogen after clover-seed, than after clover mown twice for hay.

"Reasons are given in the beginning of this paper which it is hoped will have convinced the reader, that the fertility of land is not so much measured by the amount of ash constituents of plants which it contains, as by the amount of nitrogen, which, together with an excess of such ash constituents, it contains in an available form. It has been shown likewise, that the removal from the soil of a large amount of mineral matter in a good clover-crop, in conformity with many direct field experiments, is not likely in any degree to affect the wheat-crop, and that the yield of wheat on soils under ordinary cultivation, according to the experience of many farmers, and the direct and numerous experiments of Messrs. Lawes and Gilbert, rises or falls, other circumstances being equal, with the supply of available nitrogenous food which is given to the wheat. This being the case, we can not doubt that the benefits arising from the growth of clover to the succeeding wheat, are mainly due to the fact that an immense amount of nitrogenous food accumulates in the soil during the growth of clover.

"This accumulation of nitrogenous plant-food, specially useful to cereal crops, is, as shown in the preceding experiments, much greater when clover is grown for seed, than when it is made into hay. This affords an intelligible explanation of a fact long observed by good practical men, although denied by others who decline to accept their experience as resting upon trustworthy evidence, because, as they say, land cannot become more fertile when a crop is grown upon it for seed, which is carried off, than when that crop is cut down and the produce consumed on the land. The chemical points brought forward in the course of this inquiry, show plainly that mere speculation as to what can take place in a soil, and what not, do not much advance the true theory of certain agricultural practices. It is only by carefully investigating subjects like the one under consideration, that positive proofs are given, showing the correctness of intelligent observers in the fields. Many years ago, I made a great many experiments relative to the chemistry of farm-yard manure, and then showed, amongst other particulars, that manure, spread at once on the land, need not there and then be plowed in, inasmuch as neither a broiling sun, nor a sweeping and drying wind will cause the slightest loss of ammonia; and that, therefore, the old-fashioned farmer who carts his manure on the land as soon as he can, and spreads it at once, but who plows it in at his convenience, acts in perfect accordance with correct chemical principles involved in the management of farm-yard manure. On the present occasion, my main object has been to show, not merely by reasoning on the subject, but by actual experiments, that the larger the amounts of nitrogen, potash, soda, lime, phosphoric acid, etc., which are removed from the land in a clover-crop, the better it is, nevertheless, made thereby for producing in the succeeding year an abundant crop of wheat, other circumstances being favorable to its growth.

"Indeed, no kind of manure can be compared in point of efficacy for wheat, to the manuring which the land gets in a really good crop of clover. The farmer who wishes to derive the full benefit from his clover-lay, should plow it up for wheat as soon as possible in the autumn, and leave it in a rough state as long as is admissible, in order that the air may find free access into the land, and the organic remains left in so much abundance in a good crop of clover be changed into plant-food; more especially, in other words, in order that the crude nitrogenous organic matter in the clover-roots and decaying leaves, may have time to become transformed into ammoniacal compounds, and these, in the course of time, into nitrates, which I am strongly inclined to think is the form in which nitrogen is assimilated, par excellence by cereal crops, and in which, at all events, it is more efficacious than in any other state of combination wherein it may be used as a fertilizer.

"When the clover-lay is plowed up early, the decay of the clover is sufficiently advanced by the time the young wheat-plant stands in need of readily available nitrogenous food, and this being uniformly distributed through the whole of the cultivated soil, is ready to benefit every single plant. This equal and abundant distribution of food, peculiarly valuable to cereals, is a great advantage, and speaks strongly in favor of clover as a preparatory crop for wheat.

"Nitrate of soda, an excellent spring top-dressing for wheat and cereals in general, in some seasons fails to produce as good an effect as in others. In very dry springs, the rainfall is not sufficient to wash it properly into the soil and to distribute it equally, and in very wet seasons it is apt to be washed either into the drains or into a stratum of the soil not accessible to the roots of the young wheat. As, therefore, the character of the approaching season can not usually be predicted, the application of nitrate of soda to wheat is always attended with more or less uncertainty.

"The case is different, when a good crop of clover-hay has been obtained from the land on which wheat is intended to be grown afterwards. An enormous quantity of nitrogenous organic matter, as we have seen, is left in the land after the removal of the clover-crop; and these remains gradually decay and furnish ammonia, which at first and during the colder months of the year, is retained by the well known absorbing properties which all good wheat-soils possess. In spring, when warmer weather sets in, and the wheat begins to make a push, these ammonia compounds in the soil are by degrees oxidized into nitrates; and as this change into food peculiarly favorable to young cereal plants, proceeds slowly but steadily, we have in the soil itself, after clover, a source from which nitrates are continuously produced; so that it does not much affect the final yield of wheat, whether heavy rains remove some or all of the nitrate present in the soil. The clover remains thus afford a more continuous source from which nitrates are produced, and greater certainty for a good crop of wheat than when recourse is had to nitrogenous top-dressings in the spring.


"The following are some of the chief points of interest which I have endeavored fully to develope in the preceding pages:

"1. A good crop of clover removes from the soil more potash, phosphoric acid, lime, and other mineral matters, which enter into the composition of the ashes of our cultivated crops, than any other crop usually grown in this country.

"2. There is fully three times as much nitrogen in a crop of clover as in the average produce of the grain and straw of wheat per acre.

"3. Notwithstanding the large amount of nitrogenous matter and of ash-constituents of plants, in the produce of an acre, clover is an excellent preparatory crop for wheat.

"4. During the growth of clover, a large amount of nitrogenous matter accumulates in the soil.

"5. This accumulation, which is greatest in the surface soil, is due to decaying leaves dropped during the growth of clover, and to an abundance of roots, containing, when dry, from one and three-fourths to two per cent of nitrogen.

"6. The clover-roots are stronger and more numerous, and more leaves fall on the ground when clover is grown for seed, than when it is mown for hay; in consequence, more nitrogen is left after clover-seed, than after hay, which accounts for wheat yielding a better crop after clover-seed than after hay.

"7. The development of roots being checked, when the produce, in a green condition, is fed off by sheep, in all probability, leaves still less nitrogenous matter in the soil than when clover is allowed to get riper and is mown for hay; thus, no doubt, accounting for the observation made by practical men, that, notwithstanding the return of the produce in the sheep excrements, wheat is generally stronger, and yields better, after clover mown for hay, than when the clover is fed off green by sheep.

"8. The nitrogenous matters in the clover remains, on their gradual decay, are finally transformed into nitrates, thus affording a continuous source of food on which cereal crops specially delight to grow.

"9. There is strong presumptive evidence that the nitrogen which exists in the air, in shape of ammonia and nitric acid, and descends, in these combinations, with the rain which falls on the ground, satisfies, under ordinary circumstances, the requirements of the clover-crop. This crop causes a large accumulation of nitrogenous matters, which are gradually changed in the soil into nitrates. The atmosphere thus furnishes nitrogenous food to the succeeding wheat indirectly, and, so to say, gratis.

"10. Clover not only provides abundance of nitrogenous food, but delivers this food in a readily available form (as nitrates), more gradually and continuously, and, consequently, with more certainty of a good result, than such food can be applied to the land in the shape of nitrogenous spring top-dressings."

"Thank you Charley," said the Doctor, "that is the most remarkable paper I ever listened to. I do not quite know what to think of it. We shall have to examine it carefully."

"The first three propositions in the Summary," said I, "are unquestionably true. Proposition No. 4, is equally true, but we must be careful what meaning we attach to the word 'accumulate.' The idea is, that clover gathers up the nitrogen in the soil. It does not increase the absolute amount of nitrogen. It accumulates it—brings it together.

"Proposition No. 5, will not be disputed; and I think we may accept No. 6, also, though we can not be sure that allowing clover to go to seed, had anything to do with the increased quantity of clover-roots.

"Proposition No. 7, may or may not be true. We have no proof, only a 'probability;' and the same may be said in regard to propositions Nos. 8, 9, and 10."

The Deacon seemed uneasy. He did not like these remarks. He had got the impression, while Charley was reading, that much more was proved than Dr. Voelcker claims in his Summary.

"I thought," said he, "that on the part of the field where the clover was allowed to go to seed, Dr. Voelcker found a great increase in the amount of nitrogen."

"That seems to be the general impression," said the Doctor, "but in point of fact, we have no proof that the growth of clover, either for hay or for seed, had anything to do with the quantity of nitrogen and phosphoric acid found in the soil. The facts given by Dr. Voelcker, are exceedingly interesting. Let us look at them:

"A field of 11 acres was sown to winter-wheat, and seeded down in the spring, with 13 lbs. per acre of clover. The wheat yielded 40 bushels per acre. The next year, on the 25th of June, the clover was mown for hay. We are told that 'the best part of the field yielded three tons (6,720 lbs.) of clover-hay per acre; the whole field averaging 2-1/2 tons (5,600 lbs.) per acre.'

"We are not informed how much land there was of the 'best part,' but assuming that it was half the field, the poorer part must have yielded only 4,480 lbs. of hay per acre, or only two-thirds as much as the other. This shows that there was considerable difference in the quality or condition of the land.

"After the field was mown for hay, it was divided into two parts: one part was mown again for hay, August 21st, and yielded about 30 cwt. (3,360 lbs.) of hay per acre; the other half was allowed to grow six or seven weeks longer, and was then (October 8th), cut for seed. The yield was a little over 5-1/2 bushels of seed per acre. Whether the clover allowed to grow for seed, was on the richer or poorer half of the field, we are not informed.

"Dr. Voelcker then analyzed the soil. That from the part of the field mown twice for hay, contained per acre:

First six Second six Third six Total, 18 inches. inches. inches. inches deep. Phosphoric acid 4,950 2,725 3,575 11,250 Nitrogen 3,350 1,875 1,325 6,550

"The soil from the part mown once for hay, and then for seed, contained per acre:

First six Second six Third six Total, 18 inches. inches. inches. inches deep. Phosphoric acid 3,975 4,150 3,500 11,625 Nitrogen 4,725 3,350 2,225 10,300

"Dr. Voelcker also ascertained the amount and composition of the clover-roots growing in the soil on the two parts of the field. On the part mown twice for hay, the roots contained per acre 24-1/2 lbs. of nitrogen. On the part mown once for hay, and then for seed, the roots contained 51-1/2 lbs. of nitrogen per acre."

"Now," said the Doctor, "these facts are very interesting, but there is no sort of evidence tending to show that the clover has anything to do with increasing or decreasing the quantity of nitrogen or phosphoric acid found in the soil."

"There was more clover-roots per acre, where the clover was allowed to go to seed. But that may be because the soil happened to be richer on this part of the field. There was, in the first six inches of the soil, 3,350 lbs. of nitrogen per acre, on one-half of the field, and 4,725 lbs. on the other half; and it is not at all surprising that on the latter half there should be a greater growth of clover and clover-roots. To suppose that during the six or seven weeks while the clover was maturing its seed, the clover-plants could accumulate 1,375 lbs. of nitrogen, is absurd."

"But Dr. Voelcker," said the Deacon, "states, and states truly, that 'more leaves fall on the ground when clover is grown for seed, than when it is mown for hay; and, consequently, more nitrogen is left after clover-seed than after hay, which accounts for wheat yielding a better crop after clover-seed than after hay.'"

"This is all true," said the Doctor, "but we can not accept Dr. Voelcker's analyses as proving it. To account in this way for the 1,375 lbs. of nitrogen, we should have to suppose that the clover-plants, in going to seed, shed one hundred tons of dry clover-leaves per acre! The truth of the matter seems to be, that the part of the field on which the clover was allowed to go to seed, was naturally much richer than the other part, and consequently produced a greater growth of clover and clover-roots."

We can not find anything in these experiments tending to show that we can make land rich by growing clover and selling the crop. The analyses of the soil show that in the first eighteen inches of the surface-soil, there was 6,550 lbs. of nitrogen per acre, on one part of the field, and 10,300 lbs. on the other part. The clover did not create this nitrogen, or bring it from the atmosphere. The wheat with which the clover was seeded down, yielded 40 bushels per acre. If the field had been sown to wheat again, it probably would not have yielded over 25 bushels per acre—and that for want of available nitrogen. And yet the clover got nitrogen enough for over four tons of clover-hay; or as much nitrogen as a crop of wheat of 125 bushels per acre, and 7-1/2 tons of straw would remove from the land.

Now what does this prove? There was, in 18 inches of the soil on the poorest part of the field, 6,550 lbs. of nitrogen per acre. A crop of wheat of 50 bushels per acre, and twice that weight of straw, would require about 92 lbs. of nitrogen. But the wheat can not get this amount from the soil, while the clover can get double the quantity. And the only explanation I can give, is, that the clover-roots can take up nitrogen from a weaker solution in the soil than wheat-roots can.

"These experiments of Dr. Voelcker," said I, "give me great encouragement. Here is a soil, 'originally rather unproductive, but much improved by deep culture; by being smashed up into rough clods early in autumn, and by being exposed in this state to the crumbling effects of the air.' It now produces 40 bushels of wheat per acre, and part of the field yielded three tons of clover-hay, per acre, the first cutting, and 5-1/2 bushels of clover-seed afterwards—and that in a very unfavorable season for clover-seed."

You will find that the farmers in England do not expect to make their land rich, by growing clover and selling the produce. After they have got their land rich, by good cultivation, and the liberal use of animal and artificial manures, they may expect a good crop of wheat from the roots of the clover. But they take good care to feed out the clover itself on the farm, in connection with turnips and oil-cake, and thus make rich manure.

And so it is in this country. Much as we hear about the value of clover for manure, even those who extol it the highest do not depend upon it alone for bringing up and maintaining the fertility of their farms. The men who raise the largest crops and make the most money by farming, do not sell clover-hay. They do not look to the roots of the clover for making a poor soil rich. They are, to a man, good cultivators. They work their land thoroughly and kill the weeds. They keep good stock, and feed liberally, and make good manure. They use lime, ashes, and plaster, and are glad to draw manure from the cities and villages, and muck from the swamps, and not a few of them buy artificial manures. In the hands of such farmers, clover is a grand renovating crop. It gathers up the fertility of the soil, and the roots alone of a large crop, often furnish food enough for a good crop of corn, potatoes, or wheat. But if your land was not in good heart to start with, you would not get the large crop of clover; and if you depend on the clover-roots alone, the time is not far distant when your large crops of clover will be things of the past.


"We have seen that Dr. Voelcker made four separate determinations of the amount of clover-roots left in the soil to the depth of six inches. It may be well to tabulate the figures obtained:

Clover-Roots, in Six Inches of Soil, Per Acre.

- - Air-dry Nitrogen Phosphoric roots, in roots, acid in per acre. per acre. roots, per acre. - - 1st Year. No. 1. Good Clover from brow 7705 100 of the hill " 2. Bad " " " 3920 31 " " " 2d Year. " 3. Good Clover from bottom 7569 61 27 of the field " 4. Thin " " brow 8064 66 " " hill " 5. Heavy crop of first-year clover mown twice for hay 24-1/2 " 6. Heavy crop of first-year clover mown once for hay, 51-1/2 and then for seed " 7. German experiment, 10-1/4 inches deep 8921 191-1/2 74-3/4 - -

I have not much confidence in experiments of this kind. It is so easy to make a little mistake; and when you take only a square foot of land, as was the case with Nos. 5 and 6, the mistake is multiplied by 43,560. Still, I give the table for what it is worth.

Nos. 1 and 2 are from a one-year-old crop of clover. The field was a calcareous clay soil. It was somewhat hilly; or, perhaps, what we here, in Western New York, should call "rolling land." The soil on the brow of the hill, "was very stony at a depth of four inches, so that it could only with difficulty be excavated to six inches, when the bare limestone-rock made its appearance."

A square yard was selected on this shallow soil, where the clover was good; and the roots, air-dried, weighed at the rate of 7,705 lbs. per acre, and contained 100 lbs. of nitrogen. A few yards distance, on the same soil, where the clover was bad, the acre of roots contained only 31 lbs. of nitrogen per acre.

So far, so good. We can well understand this result. Chemistry has little to do with it. There was a good stand of clover on the one plot, and a poor one on the other. And the conclusion to be drawn from it is, that it is well worth our while to try to secure a good catch of clover.

"But, suppose," said the Doctor, "No. 2 had happened to have been pastured by sheep, and No. 1 allowed to go to seed, what magic there would have been in the above figures!"

Nos. 3 and 4 are from the same field, the second year. No. 4 is from a square yard of thin clover on the brow of the hill, and No. 3, from the richer, deeper land towards the bottom of the hill.

There is very little difference between them. The roots of thin clover from the brow of the hill, contain five lbs. more nitrogen per acre, than the roots on the deeper soil.

If we can depend on the figures, we may conclude that on our poor stony "knolls," the clover has larger and longer roots than on the richer parts of the field. We know that roots will run long distances and great depths in search of food and water.

Nos. 5 and 6 are from a heavy crop of one-year-old clover. No. 5 was mown twice for hay, producing, in the two cuttings, over four tons of hay per acre. No. 6 was in the same field, the only difference being that the clover, instead of being cut the second time for hay, was allowed to stand a few weeks longer to ripen its seed. You will see that the latter has more roots than the former.

There are 24-1/2 lbs. of nitrogen per acre in the one case, and 51-1/2 lbs. in the other. How far this is due to difference in the condition of the land, or to the difficulties in the way of getting out all the roots from the square yard, is a matter of conjecture.

Truth to tell, I have very little confidence in any of these figures. It will be observed that I have put at the bottom of the table, the result of an examination made in Germany. In this case, the nitrogen in the roots of an acre of clover, amounted to 191-1/2 lbs. per acre. If we can depend on the figures, we must conclude that there were nearly eight times as much clover-roots per acre in the German field, as in the remarkably heavy crop of clover in the English field No. 5.

"Yes," said the Deacon, "but the one was 10-1/4 inches deep, and the other only six inches deep; and besides, the German experiment includes the 'stubble' with the roots."

The Deacon is right; and it will be well to give the complete table, as published in the American Agriculturist:

Table Showing the Amount of Roots and Stubble Left Per Acre by Different Crops, and the Amount of Ingredients Which They Contain Per Acre.

-+ -+ + - No. of lbs. of stubble & roots No. of lbs. (dry) per acre No. of lbs. of ash, free to a depth of of Nitrogen from carbonic 10-1/4 inches. per acre. acid, per acre. -+ -+ + - Lucern (4 years old) 9,678.1 136.4 1,201.6 Red-Clover (1 year old,) 8,921.6 191.6 1,919.9 Esparsette (3 years old) 5,930.9 123.2 1,023.4 Rye 5,264.6 65.3 1,747.8 Swedish Clover 5,004.3 102.3 974.6 Rape 4,477. 56.5 622.3 Oats 3,331.9 26.6 1,444.7 Lupine 3,520.9 62.2 550. Wheat 3,476. 23.5 1,089.8 Peas 3,222.5 55.6 670.7 Serradella 3,120.1 64.8 545.6 Buckwheat 2,195.6 47.9 465.5 Barley 1,991.4 22.8 391.1 -+ -+ + -

Contents of the Ashes, in Pounds, Per Acre.

- - - - - - Lime. Magnesia. Potash. Soda. Sulphuric Phosphoric Acid. Acid. - - - - - - Lucern 197.7 24.2 36.7 26.4 18.7 38.5 Red-Clover 262.9 48.4 58.3 20.0 26.1 74.8 Esparsette 132.8 28.7 42.6 13.8 20.6 29.7 Rye 73.2 14.3 31.2 43.3 11.8 24.4 Swedish Clover 136.1 17.6 25.9 5.7 13.2 24.2 Rape 163.9 12.9 34.7 20.9 30.8 31.9 Oats 85.5 11.2 24.8 18. 8.8 29. Lupine 80.5 11.2 16.5 3.5 7. 13.8 Wheat 76.7 10.1 28.4 11. 7.4 11.8 Peas 71.7 11. 11.2 7. 9.4 14.3 Serradella 79.8 13.4 8.8 4.8 9. 18.4 Buckwheat 80. 7.2 8.8 4.2 6.6 11. Barley 42.2 5.5 9.5 3.5 5.5 11.2 - - - - - -

It may be presumed, that, while these figures are not absolutely, they are relatively, 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 3-1/4 tons of dry roots 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 3-1/4 tons of dry clover-roots contain 191-1/2 lbs. of nitrogen, which is as much as is contained in 19 tons of ordinary stable-manure. The clover-roots also contain 74-3/4 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 and spread 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 to manure 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 the manure that 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 the crops, 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 to drill in the manure with the seed than to sow it broadcast.

My own opinion is, that these superphosphates are not the most economical 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.

Experiments at Rothamsted on the Growth of Wheat, Year After Year, on the Same Land.

Table 1.—Manures And Produce; 1st Season, 1843-4. Manures and Seed (Old Red Lammas) Sown Autumn 1843.

Manures: FM Farmyard Manure. FMA Farmyard Manure Ashes.[1] SiP Silicate of Potass.[2] PhP Phosphate of Potass.[3] PhS Phosphate of Soda.[3] PhM Phosphate of Magnesia.[3] SPL Superphosphate of Lime.[3] SAm Sulphate of Ammonia. RC Rape Cake.

- - P Manures per Acre. l - - - - - - - - - o t s FM FMA SiP PhP PhS PhM SPL SA RC - - - - - - - - - - Tons. Cwts. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0 Mixture of the residue of most of the other manures. 1 .. .. .. .. .. .. 700 .. 154 2 14 .. .. .. .. .. .. .. .. 3 Unmanured. .. .. .. .. .. .. .. 4 .. 32[1] .. .. .. .. .. .. .. 5 .. .. .. .. .. .. 700 .. .. 6 .. .. .. .. .. 420 350 .. .. 7 .. .. .. .. 325 .. 350 .. .. 8 .. .. .. 375 .. .. 350 .. .. 9 .. .. .. .. .. .. 630 65 .. 10 .. .. 220 .. .. .. 560 .. .. 11 .. .. .. .. .. .. 350 .. 308 12 .. .. .. .. 162-1/2 210 350 .. .. 13 .. .. .. 187-1/2 .. 210 350 .. .. 14 .. .. 275 .. .. 210 350 .. .. 15 .. .. 110 150 .. 168 350 .. .. 16 .. .. 110 75 65 84 350 65 .. 17 .. .. 110 75 65 84 350[4] 65 .. 18 .. .. 110 75 65 84 350 65 154 19 .. .. 110 .. 81 105 350 81 .. 20 Unmanured. .. .. .. .. .. .. .. 21 Mixture of the residue of most of the .. .. .. 22 other manures. .. .. .. .. .. .. - - - - - - - - - -

Produce: Wt/Bu Weight per Bushel. OC Offal Corn.[5] C Corn. TC Total Corn. S&C Straw and Chaff. TP Total Produce. TP Total Produce (Corn and Straw). C100 Corn to 100 Straw.

- - - - Increase per Produce per Acre, etc. Acre by Manure. P - - - - - - - l Dressed corn. o - t Qty.[5] Wt/Bu OC TC S&C TP C S&C TP C100 s - - - - - - - - - Bu. Pks. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 19 3-3/4 58.5 61 1228 1436 2664 305 316 621 85.5 0 16 3 59.0 52 1040 1203 2243 117 83 200 86.4 1 20 1-3/4 59.3 64 1276 1476 2752 353 356 709 86.4 2 15 0 58.5 46 923 1120 2043 .. .. .. 82.4 3 14 2-1/4 58.0 44 888 1104 1992 -35 -16 -51 80.4 4 15 2-1/4 58.3 48 956 1116 2072 33 -4 29 85.6 5 15 1 60.0 48 964 1100 2064 41 -20 21 87.6 6 15 2 60.3 49 984 1172 2156 61 52 113 84.0 7 15 0-3/4 61.3 49 980 1160 2140 57 40 97 84.5 8 19 2-1/4 62.3 54 1280 1368 2048 357 248 605 93.5 9 15 1-3/4 62.0 50 1008 1112 2120 85 -8 77 90.6 10 17 0-3/4 61.8 56 1116 1200 2316 193 80 273 93.0 11 15 2 61.5 50 1004 1116 2120 81 -4 77 90.0 12 16 1-1/4 62.5 54 1072 1204 2276 149 84 233 89.0 13 15 3 61.3 51 1016 1176 2192 93 56 149 86.4 14 16 3-1/4 62.0 58 1096 1240 2336 173 120 293 88.4 15 19 3-1/4 62.5 65 1304 1480 2784 381 360 741 88.1 16 18 3-3/4 62.3 62 1240 1422 2662 317 302 619 87.2 17 20 3-3/4 62.0 63 1368 1768 3136 415 618 1093 77.4 18 24 1-1/4 61.8 79 1580 1772 3352 657 652 1309 89.2 19 .. .. .. .. .. .. .. .. .. .. .. 20 .. .. .. .. .. .. .. .. .. .. .. 21 .. .. .. .. .. .. .. .. .. .. .. 22 - - - - - - - - -

[Note 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.]

[Note 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.]

[Note 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.]

[Note 4: Made with unburnt bones.]

[Note 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. less straw 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 19-1/2 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 11-1/2 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 24-1/4 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 and carbonaceous 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 least ten times as 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:

Experiments at Rothamsted on the Growth of Wheat, Year After Year, on The Same Land.

Table II.—Manures and Produce; 2nd Season, 1845. Manures and Seed (Old Red Lammas) Sown March 1845.

Manures: FM Farmyard Manure. SiP Silicate of Potass.[1] PhP Phosphate of Potass.[2] SPL Superphosphate of Lime.[2] B-A Bone-ash. MAc Muriatic Acid. G Guano. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. CAm Carbonate of Ammonia. RC Rape Cake. T Tapioca.

-+ + P Manures per Acre. l + -+ + + + + + + + + + + + o t s FM SiP PhP SPL B-A MAc G SAm MAm CAm RC T -+ -+ + + + + + + + + + + + Tons. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0 Mixture of the residue of most of the other manures. 1 .. 112 .. .. .. .. .. 224 .. .. 560 .. 2 14 .. .. .. .. .. .. .. .. .. .. .. 3 Unmanured. .. .. .. .. .. .. .. .. .. .. 4 .. .. .. .. 112 112 .. 112 .. .. .. .. 5[4]{1 Unmanured. .. .. .. .. .. .. .. .. .. {2 .. .. .. .. .. .. .. .. .. 252[3] .. .. 6 .. .. .. 112 .. .. .. 112 .. .. 560 .. 7 .. .. .. 112 .. .. .. 112 .. .. .. 560 8 .. .. .. .. .. .. .. 112 .. .. 560 .. 9 .. .. .. .. .. .. .. 168[5] 166[5] .. .. .. 10 .. .. .. .. .. .. .. 168[6] 168[6] .. .. .. 11 .. .. .. 280 .. .. .. 224 .. .. 560 .. 12 .. .. 280 .. .. .. .. 224 .. .. .. .. 13 .. .. .. .. .. .. 336[7] .. .. .. .. .. 14 .. .. .. .. .. .. 672[8] .. .. .. .. .. 15 .. .. .. .. 224 224 .. 224 .. .. .. .. 16 .. .. .. 224 .. .. .. 56 56 .. 560 .. 17 .. .. .. 224 .. .. .. 112 112 .. 280 .. 18 .. .. .. 336 .. .. .. 112 112 .. .. .. 19 .. .. .. .. 112 112 .. 112 .. .. 390 .. 20 Unmanured. .. .. .. .. .. .. .. .. .. .. 21} Mixture of the residue of most of the .. .. .. .. .. 22} other manures. .. .. .. .. .. .. .. .. .. -+ -+ + + + + + + + + + + +

Produce: Wt/Bu Weight per Bushel. OC Offal Corn.[5] C Corn. TC Total Corn. S&C Straw and Chaff. TP Total Produce. TP/C&S Total Produce (Corn and Straw). OCD Offal Corn to 100 Dressed. C100 Corn to 100 Straw.

- - Increase per Produce per Acre, etc. Acre by Manure. P - l Dressed corn. o - TP t Qty.[5] Wt/Bu OC TC S&C TP C S&C C&S OCD C100 s - - - Bu. Pks. lbs. lbs. lbs. lbs. lbs. lbs lbs. lbs. 32 0 56.5 159 1967 3977 5944 526 1265 1791 10.9 49.5 0 26 1-1/4 54.8 248 1689 3699 5388 248 987 1235 17.3 45.7 1 32 0 56.8 151 1967 3915 5882 526 1203 1729 8.9 50.2 2 23 0-3/4 56.5 131 1441 2712 4153 .. .. .. 8.7 53.1 3 29 2-1/2 58.0 161 1879 3663 5542 438 951 1389 9.4 51.3 4 22 2-1/4 57.5 134 1431 2684 4115 -10 -28 -38 10.1 53.3 1}5 26 3-3/4 57.3 190 1732 3599 5331 291 887 1178 14.2 48.1 2} 28 2-3/4 57.8 214 1871 3644 5515 430 932 1362 14.1 57.3 6 26 2-3/4 57.0 161 1682 3243 4925 241 531 772 11.3 51.9 7 27 0-1/2 56.3 164 1716 3663 5379 275 951 1226 14.0 46.9 8 33 1-1/2 58.3 187 2131 4058 6189 690 1346 2036 10.2 52.5 9 31 3-1/4 56.3 191 1980 4266 6216 539 1554 2093 12.3 46.4 10 30 3 56.0 158 1880 4101 5981 439 1392 1831 11.3 45.8 11 28 2-1/4 55.8 264 1842 4134 5976 401 1422 1823 17.8 44.5 12 25 0 56.3 152 1558 3355 4913 117 643 760 12.0 46.4 13 27 1 57.5 176 1743 3696 5439 302 981 1286 16.2 47.1 14 32 3-3/4 57.3 209 2103 4044 6147 662 1332 1994 11.8 52.0 15 32 2-1/4 56.3 182 2028 4191 6219 587 1479 2066 11.1 48.4 16 32 0-3/4 55.8 299 2093 3826 5919 652 1114 1766 15.2 54.7 17 33 1-1/4 56.5 180 2948 3819 3867 607 1107 1714 11.2 53.6 18 34 3 57.0 133 2114 4215 6329 673 1503 2176 9.1 50.2 19 24 2-3/4 56.0 113 1495 3104 4599 54 392 446 9.7 48.2 20 .. .. .. .. .. .. .. .. .. .. .. .. 21 .. .. .. .. .. .. .. .. .. .. .. .. 22 - - -

[Note 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.]

[Note 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 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 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.]

[Note 3: The medicinal carbonate of ammonia; it was dissolved in water and top-dressed.]

[Note 4: Plot 5, was 2 lands wide (in after years, respectively, 5a and 5b); 5.1 consisting of 2 alternate one-fourth lengths across both lands, and 5.2 of the 2 remaining one-fourth lengths.]

[Note 5: Top-dressed at once.]

[Note 6: Top-dressed at 4 intervals.]

[Note 7: Peruvian.]

[Note 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 an increase of only 5-1/4 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 no mineral matter 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 to 4 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 the increase from 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 manure early in 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 manure would in the course of a few years make the land too rich 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."

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