Here again, I want the Deacon to look at plot 0, where 500 lbs. Peruvian guano, sown in October, gives an increase of nearly 14 bushels of dressed wheat and 1,375 lbs. of straw per acre. On plot 2, where 14 tons of barn-yard manure have now been applied four years in succession (56 tons in all), there is a little more straw, but not quite so much grain, as from the 500 lbs. of guano.

“But will the guano,” said the Deacon, “be as lasting as the manure?”

“Not for wheat,” said I. “But if you seed the wheat down with clover, as would be the case in this section, we should get considerable benefit, probably, from the guano. If wheat was sown after the wheat, the guano applied the previous season would do little good on the second crop of wheat. And yet it is a matter of fact that there would be a considerable proportion of the guano left in the soil. The wheat cannot take it up. But the clover can. And we all know that if we can grow good crops of clover, plowing it under, or feeding it out on the land, or making it into hay and saving the manure obtained from it, we shall thus be enabled to raise good crops of wheat, barley, oats, potatoes, and corn, and in this sense guano is a ‘lasting’ manure.”

“Barnyard-manure,” said the Doctor, “is altogether too ‘lasting.’ Here we have had 56 tons of manure on an acre of land in four years, and yet an acre dressed with 500 lbs. of guano produces just as good a crop. The manure contains far more plant-food, of all kinds, than the guano, but it is so ‘lasting’ that it does not do half as much good as its composition would lead us to expect. Its ‘lasting’ properties are a decided objection, rather than an advantage. If we could make it less lasting—in other words, if we could make it act quicker, it would produce a greater effect, and possess a greater value. In proportion to its constituents, the barn-yard manure is far cheaper than the guano, but it has a less beneficial effect, because these constituents are not more completely decomposed and rendered available.”

“That,” said I, “opens up a very important question. We have more real value in manure than most of us are as yet able to bring out and turn to good account. The sandy-land farmer has an advantage over the clay-land farmer in this respect. The latter has a naturally richer soil, but it costs him more to work it, and manure does not act so rapidly. The clay-land farmer should use his best endeavors to decompose his manure.”

“Yes,” said the Doctor, “and, like John Johnston, he will probably find it to his advantage to use it largely as a top-dressing on the surface. Exposing manure to the atmosphere, spread out on the land for several months, and harrowing it occasionally, will do much to render its constituents available. But let us return to Mr. Lawes’ wonderful experiments.”

“On eight plots,” said I, “300 lbs. of ammonia-salts were used without any other manures, and the average yield on these eight plots was nearly 26 bushels per acre, or an average increase of 9 bushels per acre. The same amount of ammonia-salts, with the addition of superphosphate of lime, gave an increase of 13 bushels per acre. 400 lbs. ammonia salts, with superphosphate of lime, gave an increase of nearly 16 bushels per acre, or three bushels per acre more than where 14 tons of barn-yard manure had been used four years in succession.

“I hope, after this, the Deacon will forgive me for dwelling on the value of available nitrogen or ammonia as a manure for wheat.”

“I see,” said the Deacon, “that ground rice was used this year for manure; and in 1845, tapioca was also used as a manure. The Connecticut Tobacco growers a few years since used corn-meal for manure, and you thought it a great waste of good food.”

I think so still. But we will not discuss the matter now. Mr. Lawes wanted to ascertain whether carbonaceous matter was needed by the growing wheat-plants, or whether they could get all they needed from the soil and the atmosphere. The enormous quantities of carbonaceous matter supplied by the barn-yard manure, it is quite evident, are of little value as a manure for wheat. And the rice seems to have done very little more good than we should expect from the 22 lbs. of nitrogen which it contained. The large quantity of carbonaceous matter evidently did little good. Available carbonaceous matter, such as starch, sugar, and oil, was intended as food for man and beast—not as food for wheat or tobacco.

The following table gives the results of the experiments the fifth year, 1847-8.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE V.—MANURES AND PRODUCE; 5TH SEASON, 1847-8. MANURES AND SEED (OLD RED LAMMAS) SOWN AUTUMN, 1847.

This season was considered unfavorable for wheat. The continuously unmanured plot produced 14¾ bushels, and the plot receiving 14 tons of barn yard manure, 25¾ bushels per acre nearly.

300 lbs. of ammonia-salts alone on plot 10a, gave 19¼ bushels per acre, while the same quantity of ammonia, with superphosphate in addition, gave, on plot 9b, 25 bushels per acre.

The addition to the above manures of 300 lbs. of potash, 200 lbs. soda, and 100 lbs. sulphate of magnesia, on plot 10b, gave precisely the same yield per acre as the ammonia and the superphosphate alone. The potash, soda, and magnesia, therefore, did no good.

400 lbs. of ammonia-salts, with superphosphate, potash, etc., gave, on plot 17b, nearly 29 bushels per acre, or 3½ bushels more than the plot which has now received 70 tons of barn-yard manure in five successive years.

“I see that, on plot 0,” said the Deacon, “one ton of superphosphate was used per acre, and it gave only half a bushel per acre more than 350 lbs. on 9a.”

“This proves,” said I, “that an excessive dose of superphosphate will do no harm. I am not sure that 100 lbs. of a good superphosphate drilled in with the seed, would not have done as much good as a ton per acre.”

“You say,” remarked the Deacon, “that the season was unfavorable for wheat. And yet the no-manure plot produced nearly 15 bushels of wheat per acre.”

“That is all true,” said I, “and yet the season was undoubtedly an unfavorable one. This is shown not only in the less yield, but in the inferior quality of the grain. The ‘dressed corn’ on the no-manure plot this year only weighed 57⅓ lbs. per bushel, while last year it weighed 61 lbs. per bushel.”

“By the way,” said the Doctor, “what do Messrs. Lawes and Gilbert mean by ‘dressed corn’?”

“By ‘corn,’” said I, “they mean wheat; and by ‘dressed corn’ they mean wheat that has been run through a fanning-mill until all the light and shrunken grain is blown or sieved out. In other words, ‘dressed corn’ is wheat carefully cleaned for market. The English farmers take more pains in cleaning their grain than we do. And this ‘dressed corn’ was as clean as a good fanning-mill could make it. You will observe that there was more ‘offal corn’ this year than last. This also indicates an unfavorable season.”

“It would have been very interesting,” said the Doctor, “if Messrs. Lawes and Gilbert had analyzed the wheat produced by the different manures, so that we might have known something in regard to the quality of the flour as influenced by the use of different fertilizers.”

“They did that very thing,” said I, “and not only that, but they made the wheat grown on different plots, into flour, and ascertained the yield of flour from a given weight of wheat, and the amount of bran, middlings, etc., etc. They obtained some very interesting and important results. I was there at the time. But this is not the place to discuss the question. I am often amused, however, at the remarks we often hear in regard to the inferior quality of our wheat as compared to what it was when the country was new. Many seem to think that ‘there is something lacking in the soil’—some say potash, and some phosphates, and some this, and some that. I believe nothing of the kind. Depend upon it, the variety of the wheat and the soil and season have much more to do with the quality or strength of the flour, than the chemical composition of the manures applied to the land.”

“At any rate,” said the Doctor, “we may be satisfied that anything that will produce a vigorous, healthy growth of wheat is favorable to quality. We may use manures in excess, and thus produce over-luxuriance and an unhealthy growth, and have poor, shrunken grain. In this case, it is not the use, but the abuse of the manure that does the mischief. We must not manure higher than the season will bear. As yet, this question rarely troubles us. Hitherto, as a rule, our seasons are better than our farming. It may not always be so. We may find the liberal use of manure so profitable that we shall occasionally use it in excess. At present, however, the tendency is all the other way. We have more grain of inferior quality from lack of fertility than from an excess of plant-food.”

“That may be true,” said I, “but we have more poor, inferior wheat from lack of draining and good culture, than from lack of plant-food. Red-root, thistles, cockle, and chess, have done more to injure the reputation of ‘Genesee Flour,’ than any other one thing, and I should like to hear more said about thorough cultivation, and the destruction of weeds, and less about soil exhaustion.”

The following table shows the results of the experiments the sixth year, 1848-9.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VI.—MANURES AND PRODUCE; 6TH SEASON, 1848-9. MANURES AND SEED (RED CLUSTER), SOWN AUTUMN, 1848.

“This was my last year at Rothamsted,” said I, “and I feel a peculiar interest in looking over the results after such a lapse of time. When this crop was growing, my father, a good practical farmer, but with little faith in chemical manures, paid me a visit. We went to the experimental wheat-field. The first two plots, 0 and 1, had been dressed, the one with superphosphate, the other with potash, soda, and magnesia. My father did not seem much impressed with this kind of chemical manuring. Stepping to the next plot, where 14 tons of barn-yard manure had been used, he remarked, “this is good, what have you here?”

“Never mind,” said I, “we have better crops farther on.”

The next plot, No. 3, was the one continuously unmanured. “I can beat this myself,” said he, and passed on to the next. “This is better,” said he, “what have you here?”

“Superphosphate and sulphate of ammonia.”

“Well, it is a good crop, and the straw is bright and stiff.”—It turned out 30 bushels per acre, 63 lbs. to the bushel.

The next six plots had received very heavy dressings of ammonia-salts, with superphosphate, potash, soda, and magnesia. He examined them with the greatest interest. “What have you here?” he asked, while he was examining 5a, which afterwards turned out 37¼ bushels per acre. —“Potash, soda, epsom-salts, superphosphate, and ammonia—but it is the ammonia that does the good.”

He passed to the next plot, and was very enthusiastic over it. “What have you here?” —“Rape-cake and ammonia,” said I. —“It is a grand crop,” said he, and after examining it with great interest, he passed to the next, 6a. —“What have you here?” —“Ammonia,” said I; and at 6b he asked the same question, and I replied “ammonia.” At 7a, the same question and the same answer. Standing between 7b and 8a, he was of course struck with the difference in the crop; 8a was left this year without any manure, and though it had received a liberal supply of mineral manures the year before, and minerals and ammonia-salts, and rape-cake, the year previous, it only produced this year, 3½ bushels more than the plot continuously unmanured. The contrast between the wheat on this plot and the next one might well interest a practical farmer. There was over 15 bushels per acre more wheat on the one plot than on the other, and 1,581 lbs. more straw.

Passing to the next plot, he exclaimed “this is better, but not so good as some that we have passed.” —“It has had a heavy dressing of rape-cake,” said I, “equal to about 100 lbs. of ammonia per acre, and the next plot was manured this year in the same way. The only difference being that one had superphosphate and potash, soda, and magnesia, the year before, while the other had superphosphate alone.” It turned out, as you see from the table, that the potash, etc., only gave half a bushel more wheat per acre the year it was used, and this year, with 2,000 lbs. of rape-cake on each plot, there is only a bushel per acre in favor of the potash, soda, and magnesia.

The next plot, 9b, was also unmanured and was passed by my father without comment. “Ah,” said he, on coming to the two next plots, 10a and 10b, “this is better, what have you here?” —“Nothing but ammonia,” said I, “and I wish you would tell me which is the best of the two? Last year 10b had a heavy dressing of minerals and superphosphate with ammonia, and 10a the same quantity of ammonia alone, without superphosphate or other mineral manures. And this year both plots have had a dressing of 400 lbs. each of ammonia-salts. Now, which is the best—the plot that had superphosphate and minerals last year, or the one without?” —“Well,” said he, “I can’t see any difference. Both are good crops.”

You will see from the table, that the plot which had the superphosphate, potash, etc., the year before, gives a peck less wheat this year than the other plot which had none. Practically, the yield is the same. There is an increase of 13 bushels of wheat per acre—and this increase is clearly due to the ammonia-salts alone.

The next plot was also a splendid crop.

“What have you here?”

“Superphosphate and ammonia.”

This plot (11a), turned out 35 bushels per acre. The next plot, with phosphates and ammonia, was nearly as good. The next plot, with potash, phosphates, and ammonia, equally good, but no better than 11a. There was little or no benefit from the potash, except a little more straw. The next plot was good and I did not wait for the question, but simply said, “ammonia,” and the next “ammonia,” and the next “ammonia.”—Standing still and looking at the wheat, my father asked, “Joe, where can I get this ammonia?” He had previously been a little skeptical as to the value of chemistry, and had not a high opinion of “book farmers,” but that wheat-crop compelled him to admit “that perhaps, after all, there might be some good in it.” At any rate, he wanted to know where he could get ammonia. And, now, as then, every good farmer asks the same question: “Where can I get ammonia?” Before we attempt to answer the question, let us look at the next year’s experiments.—The following is the results of the experiments the seventh year, 1849-50.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VII.—MANURES AND PRODUCE; 7TH SEASON, 1849-50. AFTER THE HARVEST OF 1849 THE FIELD WAS TILE-DRAINED IN EVERY ALTERNATE FURROW, 2 TO 3 FEET DEEP. MANURES AND SEED (RED CLUSTER), SOWN IN AUTUMN, 1849.

The summer of 1850 was unusually cool and unfavorable for wheat. It will be seen that on all the plots the yield of grain is considerably lower than last year, with a greater growth of straw.

You will notice that 10b, which last year gave, with ammonia-salts alone, 32¼ bushels, this year, with superphosphate, potash, soda, and sulphate of magnesia, gives less than 18 bushels, while the adjoining plot, dressed with ammonia, gives nearly 27 bushels. In other words, the ammonia alone gives 9 bushels per acre more than this large dressing of superphosphate, potash, etc.

On the three plots, 8a, 8b and 9a, a dressing of ammonia-salts alone gives in each case, a larger yield, both of grain and straw, than the 14 tons of barn-yard manure on plot 2. And recollect that this plot has now received 98 tons of manure in seven years.

“That,” said the Doctor, “is certainly a very remarkable fact.”

“It is so,” said the Deacon.

“But what of it?” asked the Squire, “even the Professor, here, does not advise the use of ammonia-salts for wheat.”

“That is so,” said I, “but perhaps I am mistaken. Such facts as those just given, though I have been acquainted with them for many years, sometimes incline me to doubt the soundness of my conclusions. Still, on the whole, I think I am right.”

“We all know,” said the Deacon, “that you have great respect for your own opinions.”

“Never mind all that,” said the Doctor, “but tell us just what you think on this subject.”

“In brief,” said I, “my opinion is this. We need ammonia for wheat. But though ammonia-salts and nitrate of soda can often be used with decided profit, yet I feel sure that we can get ammonia or nitrogen at a less cost per lb. by buying bran, malt-roots, cotton-seed cake, and other foods, and using them for the double purpose of feeding stock and making manure.”

“I admit that such is the case,” said the Doctor, “but here is a plot of land that has now had 14 tons of manure every year for seven years, and yet there is a plot along side, dressed with ammonia-salts furnishing less than half the ammonia contained in the 14 tons of manure, that produces a better yield of wheat.”

“That,” said I, “is simply because the nitrogen in the manure is not in an available condition. And the practical question is, how to make the nitrogen in our manure more immediately available. It is one of the most important questions which agricultural science is called upon to answer. Until we get more light, I feel sure in saying that one of the best methods is, to feed our animals on richer and more easily digested food.”

The following table gives the results of the eighth season of 1850-51.

Experiments at Rothamsted on the Growth of Wheat, Year after Year, on the same Land.

TABLE VIII.—MANURES AND PRODUCE; 8TH SEASON. 1850-51. MANURES AND SEED (RED CLUSTER), SOWN AUTUMN, 1850.

1. Top-dressed in March, 1851.

The plot continuously unmanured, gives about 16 bushels of wheat per acre.

The plot with barn-yard manure, nearly 30 bushels per acre.

400 lbs. of ammonia-salts alone, on plot 9a, 31¼ bushels; on 9b, 29 bushels; on 10a and 10b, nearly 29 bushels each. This is remarkable uniformity.

400 lbs. ammonia-salts and a large quantity of mineral manures in addition, on twelve different plots, average not quite 32 bushels per acre.

“The superphosphate and minerals,” said the Deacon, “do not seem to do much good, that is a fact.”

You will notice that 336 lbs. of common salt was sown on plot 16a. It does not seem to have done the slightest good. Where the salt was used, there is 2 lbs. less grain and 98 lbs. less straw than on the adjoining plot 16b, where no salt was used, but otherwise manured alike. It would seem, however, that the quality of the grain was slightly improved by the salt. The salt was sown in March as a top-dressing.