SIR,—I promised to communicate to you the results of my attempt to grow wheat on the same land year after year, this being the fourth crop of wheat (the fifth white crop) grown in successive years on the same soil, and though I consider the crop an indifferent one, I don't think the failure ought in any degree to be attributed to the over-cropping, but to the wetness and coldness of the season, as well as other untoward circumstances hereafter to be mentioned.
In a former letter of mine of the 12th October, 1844—which was published in the "Guardian" a few days after—I gave an account of the crop of 1844, which was a very good one, being fifty bushels to the acre throughout the field, and as much as fifty-two bushels in the best part of it. This I considered so satisfactory that I had the field again ploughed up and sowed with wheat on the 9th October, 1844, and it is to the results of this crop that I wish to call your attention. As remarked in my former letter, the field was subsoil ploughed in the autumn of 1843, and this subsoiling was carried to such a depth that most of the drains in the field were more or less injured by it; and although this did no injury to the crop of 1844, owing to the very dry season, yet when the rain came in the winter of 1844, the want of drainage was found to be very prejudicial, and in the wet places large patches of the young wheat went off altogether, and there was a great deficiency of roots in many parts of the field; the long continuance of frost and after that the ungenial weather which continued so long in the spring (of 1845) were also unfavourable, yet with all these drawbacks the appearance of the plant after the growing weather did come, was very promising, and many of my friends predicted that I should have as good a crop as in 1844. On the 24th March I applied chemical manure of the same kind as I had done in 1844, at the rate of about 3 1/4 cwt. to the acre (costing 23s. 6d.), and a fortnight after I had it sowed with 2 cwt. of guano to the acre. When the warm weather came, these manurings seemed to help it wonderfully, and it was, as I have before stated, a very promising crop; but the cold, ungenial weather we had through a great part of the summer, and the continued rain we had whilst the wheat was in flower, destroyed all the former promise: and the manuring with guano, so far from being beneficial, was very injurious—so much so, that I believe every shilling's-worth of it applied to my wheat this year, made the crop a shilling worse than if nothing had been applied; and all ammoniacal manures had the same effect. It may be asked how I know it was the guano, and not the chemical manure. In answer to this inquiry, if made, I may observe, that I supplied two of my neighbours with the chemical manure, and they applied it without guano on very poor land, and they both assert they had never such good crops of wheat before; but everywhere in this neighbourhood, the only good samples of wheat that I saw or heard of were grown on exhausted soil. This appears to me to be a strong proof that chemistry has a great deal to learn before it can adapt its measures to all varieties of seasons, particularly as it cannot know beforehand how the season may turn out. If further proof be required of the injurious effect upon grain crops of ammoniacal manures in general, and of guano in particular, I may mention that in another field of wheat, sowed on the 21st December, and which did not come up until the frost broke, in March (the previous crop having been Swedes), the blade was so yellow and the plant altogether so small and sickly in appearance, that I had it manured with a water-cart from a cesspool in April. This appeared to produce a wonderful improvement immediately, as the plant assumed a deep green and grew very fast, but when it ought to have shot, the heads seemed to stick in the sockets, the blade and straw became mildewed and made no progress in ripening. It was not fit to cut for three weeks after the experimental field, although it was an early white wheat, and the result was a miserable crop—far worse than the experimental field. The instance of injury from the use of guano, I had from a neighbour, who told me he had sowed a patch of oats with it, and that they never ripened at all, and that he was compelled to cut them green as fodder for his cattle. I had a striking proof this season of the much lower temperature required by oats than wheat, when strongly stimulated by manuring. I had gathered an ear of wheat and a panicle of oats the previous season, which seemed to me to be superior varieties; and that they might have every chance, I dibbled them alongside each other in my garden, and determined to manure them with every kind of manure I could procure, as I had an idea that it was not easy to over-manure grain crops, if all the elements entering into the composition of the plant were applied in due proportion to each other, and I also wished to ascertain whether wheat and oats would thrive equally well with the same sort of manuring. I accordingly limed the land soon after the wheat came up, and in March I applied silicate of soda, sulphate of magnesia, gypsum, common salt, and nitrate of soda. A fortnight after this I applied guano, then bones dissolved in sulphuric acid, then woollen rags dissolved in potash (the two latter in weak solution); and the consequence was, that I don't think there was a single grain in the whole parcel—at least I could not find one—the straw was no great length, and the blade much discolored with mildew, whilst the oats were seven feet high, and with straws through which I could blow a pea, and large panicles, although the oat was not particularly well-fed. The inference I have drawn from these experiments is, that as far as is practicable the manuring should be adapted to the temperature, but as this is obviously impossible in a climate like ours, the only way is to rather under than over manure, and to apply no ammoniacal manure to the wheat crop, or at all events very little; for although guano was beneficial to wheat when used in conjunction with silicates, &c. &c. in 1844, yet the injury it did in 1845 may very fairly be set against that benefit. I should feel obliged if any of your readers who may have tried the experiment of manuring grain crops with guano, the last season (1845) would publish the result as compared with a similar crop without such manuring. I feel convinced that such result would be against the use of guano for wheat in 1845. I am the more confirmed in the opinion that ammoniacal manures are unfavourable for wheat, by a series of articles in the "Gardener's Chronicle" on the "Geo-Agriculture of Middlesex," in which the writer states that land in that county which in Queen Elizabeth's time produced such good wheat that it was reserved for her especial use, will now scarcely grow wheat at all, and when that grain is sowed upon it, the straw is always mildewed, and the sample very poor; and this is attributed—and no doubt justly so—to the extensive use of London manure. My crop was only 32 bushels to the acre of 60 lbs. to the bushel; last year the crop, as I have said before, was 50 bushels of the same weight.
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To the same.
CLITHEROE, 7th March, 1848.
On continuing my attempts to grow wheat on the same land year after year, I observed that the crop of 1845 was very seriously injured by the deficient drainage—the old drains having been destroyed by the subsoil plough. It was therefore necessary to replace them: they were accordingly put in four feet deep. This occupied so much time that the season for sowing wheat had gone by, and the ground was cropped with potatoes, which were got up in September, and the wheat might have been got in early in October. But seeing in your paper that sowing too early was not advisable, and also being carried away by the arguments of the thin-seeders, I deferred sowing until the middle of November, and then put in little seed; and the winter proving very unfavourable, when the wheat was coming up, there was not half plant enough in the spring, and I hesitated whether to plough up the ground or drill in barley. I determined to do the latter, which was done on the 18th April, and wheat and barley grew up together, and when cut and threshed, proved to be equal to 48 bushels to the acre.
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LOW MOOR, 31st December, 1844.
HENRY BRIGGS, ESQ.
I duly received your obliging letter in reply to my pamphlet on the growth of wheat year after year on the same land, and now offer my rejoinder to your remarks. You seem to consider the expense is too great under the system pursued by me; and that it was more than was required by the crop, is proved in my opinion by the fact that the fertility of the land is very much augmented since the commencement of the experiment in 1841: as my first crop with guano alone produced only 27 bushels per acre, whilst this year from guano alone the produce was 42 bushels. But still I think that your allowance of manure is far too little, and not exactly what I should apply, and I shall frankly state my objections and opinions, in the hope that they may elicit a reply from you, as it will be from discussion and the experiments instituted to test the various theories propounded, that agriculture will be most materially benefited. You state that Liebig's present theory is, that plants obtain the necessary oxygen, hydrogen, carbon, and nitrogen from the rain and atmosphere, and that the plants merely require the supply of inorganic constituents, and that you are inclined to agree with him. My copy of his work on the Chemistry of Agriculture is his first edition; and I don't know how far he has since modified or altered the opinions therein expressed, which are in some degree at variance with each other. He states that it may be received as an axiom in agricultural chemistry that the nitrogen of the atmosphere is never assimilated by plants, except in the form of ammonia or nitric acid. He certainly states that plants and animals derive their nitrogen from the atmosphere; but why, if this be true, does he attach so much importance to the excrements (particularly urine), of men and animals being husbanded with so much care? and he states that for every pound of urine wasted, a pound of wheat is thrown away. But even if he said it was utterly worthless, every practical farmer who has tried it knows how exceedingly valuable it is. It may be said there are other ingredients in urine besides ammonia, and these are what make it valuable; and in reply to this I would ask what is it that makes the ammoniacal liquor from gasworks so valuable? There are no phosphates or alkalies there, and yet what a powerful stimulant it is. Again, Liebig states that the carbon is derived from the atmosphere; but to say nothing of the argument which might be deduced from the advantage which is derived by plants from having their soil loosened about their roots, the experiments of Dumas and Boussingault prove that a tree which was cut off below the branches expired a large quantity of carbonic acid. It may be asked how I know this was not precipitated by the rain. I don't know; but if the plant would assimilate this, why should it not assimilate that which arises from the decomposition of the carbonaceous matter in the soil? My idea is that it does both, and that carbon in the soil does good if it offers an abundant supply of carbonic acid to the plant when it is in a condition to appropriate it. Your allowance of lime appears to me to be far too small, for if any reliance can be placed on my experiments, lime can be profitably used to far greater extent than you seem to imagine. And, again, you seem to think that where there is plenty of silex in the soil, the plant will be able to obtain as much as it requires. I think that it is quite necessary that the silex should be in a soluble state, as I think that it is not only desirable that all the elements necessary to fertility should be in the soil, but that they should be in such a form that they can be assimilated by the plant. Some of our compounds for producing fertility may perhaps be as absurd as it would be to give muriatic acid to a man troubled with indigestion, because free muriatic acid is found in the stomach of a healthy person. Let me recommend you to try both silex and magnesia in a soluble state, and I think you will be satisfied with the benefit derived from their use.