Effects of guano upon the crop to which it is applied.—Edward Stabler, in the American Farmer, thus speaks of an experiment he made in 1845, soon after the introduction of guano to any extent into this country.

"In a field of some 10 acres, one acre was selected near the middle, and extending through the field, so as to embrace any difference of soil, should there be any. On this acre 200 lbs. of Peruvian guano, at a cost of about $5 was sown with the wheat. Adjoining the guano on one side, was manure from the barn yard, at the rate of 25 cart loads to the acre; and on the opposite side (separated by an open drain the whole distance;) ground bones were applied on the balance of the field, at a cost of $6 to the acre; the field equally limed two years preceding. There was no material difference in the time or manner of seeding; except that the manure was lightly cross-ploughed in, and the guano and bones harrowed in with the wheat.

"The yield on the guanoed acre was 35 bushels; the adjoining acre with bone, as near as could be estimated by dozens, and compared with the guano, was about 27 bushels; and the manured, about 24 bushels. The season was unusually dry; and the manured portion suffered more from this cause than either of the others; the land being considerably more elevated, and a south exposure."

In our opinion Mr. S. is in error in regard to the manured land suffering most from drouth. In our experience we have always found the best effects from Guano, in wet seasons, or upon irrigated land. He says also, "This is one of the most active of all manures; and although he thinks the effect evanescent, it might aid materially in renovating worn out lands." Since that time a great many other Maryland farmers have, undoubtedly come to the same conclusion, for notwithstanding the price, which he thinks too high to justify its extensive use, has not been materially reduced, there is more guano sold in Baltimore than any, or perhaps all the ports in the United States; and the benefits derived from its use upon the worn out lands of Maryland, have been of the most satisfactory character.

In speaking of the after crop of grass upon the land above mentioned, he says:

"The field has since been mowed three times; the first crop of grass was evidently in favor of the boned part; the second, and third, were fully two to one over the guano, and also yielding much heavier crops of clover seed. On a part of one land, 18 bushels to the acre of the finest of the bone were used; on this, the wheat was as heavy as on the guanoed, and the grass generally lodges before harvest, as it also does on much of the adjoining land with 12 bushels of bone."

This is all right; it should never be mixed with lime, and it should be plowed in. In his experiments, the lime in the soil had the effect to disengage the ammonia, and not being sufficiently buried or mixed up with the earth to prevent its escape during a very dry season, much of its value went afloat in the atmosphere. If he had given a bushel of plaster as a top dressing, there is no doubt the effect upon the grass crop would have been entirely different. The action of guano is very variable upon different soils, as well as upon the same kinds of soil in different seasons, or from the different manner of applying it; but there is one thing in its favor, it seldom fails to pay for itself, as Mr. Newton remarks, in the first crop; and if properly applied, that is, plowed in with wheat, upon poor, sandy, "worn out land," and followed by clover, and that dressed with plaster, it will pay far better in the succeeding years than the first. This has been fully proved in a hundred cases, since Mr. Stabler tried his experiments; for two years after, in writing upon the same subject, he says "Harrowing in the guano with the wheat will generally produce a better crop; but its fertilizing properties are more evanescent. I prefer plowing it in for all field crops; and when attainable, would always use it in conjunction with ground bones, for the benefit of succeeding grass crops. This is pre-supposing that you determine to improve more land than the resources of the farm will accomplish, and are willing to do it by the aid of foreign manures; and being 'far removed from lime.' If the object is to realize the most in a single crop, and to obtain the quickest return for the outlay, use the guano alone, and harrow it in with the wheat; but the land, according to my experience, will derive but little benefit from the application, unless the amount is large. By plowing it in, particularly if mixed with one third its bulk of plaster, the effect is decidedly more durable; nor is it then necessary that the seeding should so immediately follow its application. If, however, the object is to improve the land at the same time; and surely it should be a primary object with every tiller of the soil—and lime, from your location, or the price, is unattainable, I would advise about half the amount determined on, to be expended for ground bones. This may be harrowed in with the wheat."

It is surprising what an effect a few bushels of ground bones to the acre will produce; reference is made to a single experiment, and not an isolated one either. Some six years since, we applied ten to twelve bushels of coarsely ground bones to the acre, on about half of a twelve acre field; on two lands adjoining, was guano, at the rate of 200 pounds to the acre, (the cost of each about the same,) and extending nearly through the field; both were applied in the spring, on the oat crop—and which was decidedly better, by the eye, on the two lands with guano. In the fall, the field was sown with wheat, manuring heavily from the barn yard, adjoining the guano, but not spread on the two lands, or on the boned portion of the field.

There was but little difference perceived in the wheat, except from the manure, which was the best—the field having been limed for the preceding corn crop, 80 bushels to the acre. The experiment was made to test the comparative durability of the three kinds of manure; the guano, ground bones, and manure from the barn yard; and the ultimate profit to be derived from each, in a full rotation. After the first crop of grass, and perhaps the second, which was in favor of the manured portion, the succeeding crops of hay and clover seed, have been decidedly better on the boned part of the field. At the present time, and also the past season, this being the fourth year in grass, the guanoed lands present about the same appearance, that does a small adjoining space, purposely left without manure of any kind, lime excepted. The manured part affords good pasture, but is quite inferior to the boned, which would give a fair crop of hay, and probably three times as much grass as the two lands with guano. It is believed that the increased crop of clover seed on the boned, over the guanoed portion, paid for the former; and that the two crops of clover since taken from the field, have paid, or nearly so, for the lime or other manures applied.

This evidence corresponds with the opinion of Professor Mapes; that is, that the value of an application of guano is greatly enhanced by the addition of phosphate of lime, in some shape; the guano acting immediately and producing a direct profit, while the slow action, for which some farmers cannot wait, keeps up the fertility for years, or until the owner may find time to profit by another application of guano.

We quote again a few more of the very sensible remarks of friend Stabler. "I am an advocate for the liberal use of all kinds of manure, guano included, if the price will justify it. A farmer had better buy manure than to buy grain, if compelled to do either; for we cannot expect much from nothing, or reasonably calculate upon improving very poor land without manure of some description, unless plaster will act with effect; nor is this generally the case without the land possesses naturally, some particular source of fertility, not wholly exhausted by bad or improvident tillage.

"It is probable those will be disappointed who expect to do everything with guano—make fine crops and improve the land, while they take everything off, and dispense almost, if not entirely, with the more permanent manures, all equally within their reach. True, we may exist for a time, only half fed and half clothed; but it is just as reasonable to expect to improve under such a regimen, as to calculate upon continued, not to say increased fertility of the soil, without an ample supply, of the right kind of manure.

"With all its acknowledged advantages, it may be questioned whether there is not one drawback to the introduction of guano. It is used with less profit in direct connexion with lime, than with most kinds of manure; and its facility of application, and quick return, has induced many to give up the lime entirely, if not also to some extent, to neglect the resources of the farm. Others again, in improving poor land, advise the guano first, and the lime afterwards. This may do very well; but is often better in theory than in practice, for the lime is omitted altogether, and perhaps at some risk of loss, in both time and money, as regards permanent improvement. To use a figure of speech—the prudent architect will first secure a solid foundation to build upon, and with materials of known durability; this accomplished, he need have no fears of the stability of the structure, and may, at pleasure add thereto, either for ornament or utility."

"That thin lands may be brought to a very productive state, by the liberal and repeated applications of guano, there is no doubt; but at what cost and how durable the improvements might be, I am not prepared to say. In two instances, from 700 to 800 lbs. were applied at one time to an acre; but in neither did the results correspond with the expense, or induce a repetition of the experiment. My own experience so far, is in favor of more limited applications, say 100 to 200 lbs. to the acre, (taking in consideration the price of both grain and guano,) and also used in connection with other manures, which is found to be the most profitable, and probably more durable in its effect; in two experiments, with from 50 to 150 lbs. of guano to the acre applied three years since with barnyard manure, for wheat, the effect on the grass crop at this time, is quite marked; applied in this way, it hastens maturity—thus, in a degree, guarding against rust—renders the grain more perfect, and is believed to be one of the most profitable modes of using guano."

Nothing could be more sensible than the advice of this gentleman, not to rely upon guano alone. To waste or neglect stable and home made manures, or throw away bones or other valuable fertilizers, because we could buy guano, would be as insensible as it would for a man to throw away a handful of bank bills, because he happened to have just then a pocket full of gold and silver coin.

We never have, nor shall we recommend guano to the exclusion of everything else; but we do recommend every farmer in America, to whom an additional quantity of manure would be an object, to buy guano; because he will be almost sure to derive a certain and immediate profit from the investment. It will make poor lands rich, and rich lands richer.