Talks on Manures Part 35

No. 6. Gault clay 4 feet below the surface.

It is evident that lime neither a.s.sisted nor interfered with the absorption of ammonia, and hence the beneficial effect of liming on such soils must be accounted for on some other supposition. This negative result, however, does not disprove the truth of Prof. Way's hypothesis, for it may be that the silicate salt in the natural soils was that of lime and not that of soda. Indeed, the extent to which the natural soils absorbed ammonia--equal, in No. 3, to about 7,000 lbs. of ammonia per acre, equivalent to the quant.i.ty contained in 700 tons of barn-yard manure--shows this to have been the case.

_The lime liberated one-half the ammonia contained in the soil._

"This result," says Prof. Way, "is so nearly the same in all cases, that we are justified in believing it to be due to some special cause, and probably it arises from the existence of some compound silicates containing ammonia, of which lime under the circ.u.mstances can replace one-half--forming, for instance, a double silicate of alumina, with half lime and half ammonia--such compounds are not unusual or new to the chemist."

This loss of ammonia from a heavy dressing of lime is very great. A soil five inches deep, weighs, in round numbers, 500 tons, or 1,000,000 lbs.

The soil, No. 1, contained .0293 per cent of ammonia, or in an acre, five inches deep, 293 lbs. After liming, it contained .0169 per cent, or in an acre, five inches deep, 169 lbs. The loss by liming is 124 lbs. of ammonia per acre. This is equal to the quant.i.ty contained in 1200 lbs.

of good Peruvian guano, or 12 tons of barn-yard manure.

In commenting on this great loss of ammonia from liming, Prof. Way observes:

"Is it not possible, that for the profitable agricultural use, the ammonia of the soil is too tightly locked up in it? Can we suppose that the very powers of the soil to unite with and preserve the elements of manure are, however excellent a provision of nature, yet in some degree opposed to the growth of the abnormal crops which it is the business of the farmer to cultivate? There is no absolute reason why such should not be the case. A provision of nature must relate to natural circ.u.mstances; for instance, compounds of ammonia may be found in the soil, capable of giving out to the agencies of water and air quite enough of ammonia for the growth of ordinary plants and the preservation of their species; but this supply may be totally inadequate to the necessities of man.

* * * Now it is not impossible that the laws which preserve the supply of vegetable nutrition in the soil, are too stringent for the requirements of an unusual and excessive vegetation, such as the cultivator must promote.

"In the case of ammonia locked up in the soil, lime may be the remedy at the command of the farmer--his means of rendering immediately available stores of wealth, which can otherwise only slowly be brought into use.

"In this view, lime would well deserve the somewhat vague name that has been given it, namely, that of a 'stimulant'; for its application would be in some sort an application of ammonia, while its excessive application, by driving off ammonia, would lead to all the disastrous effects which are so justly attributed to it.

"I do not wish to push this a.s.sumption too far," says Prof. Way, in conclusion, "but if there be any truth in it, it points out the importance of employing lime in small quant.i.ties at short intervals, rather than in large doses once in many years."

"The Squire, last year," said the Deacon, "drew several hundred bushels of refuse lime from the kiln, and mixed it with his manure. It made a powerful smell, and not an agreeable one, to the pa.s.sers by. He put the mixture on a twenty-acre field of wheat, and he said he was going to beat you."

"Yes," said I, "so I understood--but he did not do it. If he had applied the lime and the manure separately, he would have stood a better chance; still, there are two sides to the question. I should not think of mixing lime with good, rich farm-yard manure; but with long, coa.r.s.e, strawy manure, there would be less injury, and possibly some advantage."

"The Squire," said the Deacon, "got one advantage. He had not much trouble in drawing the manure about the land. There was not much of it left."

Lime does not always decompose organic matter. In certain conditions, it will _preserve_ vegetable substances. We do not want to mix lime with manure in order to preserve it; and if our object is to increase fermentation, we must be careful to mix sufficient soil with the manure to keep it moist enough to retain the liberated ammonia.

Many farmers who use lime for the first time on wheat, are apt to feel a little discouraged in the spring. I have frequently seen limed wheat in the spring look worse than where no lime was used. But wait a little, and you will see a change for the better, and at harvest, the lime will generally give a good account of itself.

There is one thing about lime which, if generally true, is an important matter to our wheat-growers. Lime is believed to hasten the maturity of the crop. "It is true of nearly all our cultivated crops," says the late Professor Johnston, "but especially of those of wheat, that their full growth is attained more speedily when the land is limed, and that they are ready for the harvest from ten to fourteen days earlier. This is the case even with buckwheat, which becomes sooner ripe, though it yields no larger a return when lime is applied to the land on which it is grown."

In districts where the midge affects the wheat, it is exceedingly important to get a variety of wheat that ripens early; and if lime will favor early maturity, without checking the growth, it will be of great value.

A correspondent in Delaware writes: "I have used lime as a manure in various ways. For low land, the best way is, to sow it broadcast while the vegetation is in a green state, at the rate of 40 or 50 bushels to the acre; but if I can not use it before the frost kills the vegetation, I wait until the land is plowed in the spring, when I spread it on the plowed ground in about the same quant.i.ty as before. Last year, I tried it both ways, and the result was, my crop was increased at least fourfold in each instance, but that used on the vegetation was best. The soil is a low, black sand."

A farmer writes from New Jersey, that he has used over 6,000 bushels of lime on his farm, and also considerable guano and phosphates, but considers that the lime has paid the best. His farm has more than doubled in real value, and he attributes this princ.i.p.ally to the use of lime.

"We lime," he says, "whenever it is convenient, but prefer to put it on at least one year before plowing the land. We spread from 25 to 40 bushels of lime on the sod in the fall; plant with corn the following summer; next spring, sow with oats and clover; and the next summer, plow under the clover, and sow with wheat and timothy. We have a variety of soils, from a sandy loam to a stiff clay, and are certain that lime will pay on all or any of them. Some of the best farmers in our County commenced liming when the lime cost 25 cts. a bushel, and their farms are ahead yet, more in value, I judge, than the lime cost. The man who first commences using lime, will get so far ahead, while his neighbors are looking on, that they will never catch up."

Another correspondent in Hunterdon Co., N.J., writes: "Experience has taught me that the best and most profitable mode of applying lime is on gra.s.s land. If the gra.s.s seed is sown in the fall with the wheat or rye, which is the common practice with us in New Jersey, as soon as the harvest comes off the next year, we apply the lime with the least delay, and while fresh slacked and in a dry and mealy state. It can be spread more evenly on the ground, and is in a state to be more readily taken up by the fine roots of the plants, than if allowed to get wet and clammy.

It is found most beneficial to keep it as near the surface of the ground as practicable, as the specific gravity or weight of this mineral manure is so great, that we soon find it too deep in the ground for the fibrous roots of plants to derive the greatest possible benefit from its use.

With this method of application are connected several advantages. The lime can be hauled in the fall, after the busy season is over, and when spread on the sod in this way, comes in more immediate contact with the gra.s.s and gra.s.s-roots than when the land is first plowed. In fields that have been limed in part in this manner, and then plowed, and lime applied to the remainder at the time of planting with corn, I always observe a great difference in the corn-crop; and in plowing up the stubble the next season, the part limed on the sod is much mellower than that limed after the sod was broken, presenting a rich vegetable mould not observed in the other part of the field."

A farmer in Chester Co., Pa., also prefers to apply lime to newly-seeded gra.s.s or clover. He puts on 100 bushels of slaked lime per acre, either in the fall or in the spring, as most convenient. He limes one field every year, and as the farm is laid off into eleven fields, all the land receives a dressing of lime once in eleven years.

In some sections of the country, where lime has been used for many years, it is possible that part of the money might better be used in the purchase of guano, phosphates, fish-manure, etc.; while in this section, where we seldom use lime, we might find it greatly to our interest to give our land an occasional dressing of lime.

The value of quick-lime as a manure is not merely in supplying an actual const.i.tuent of the plant. If it was, a few pounds per acre would be sufficient. Its value consists in changing the chemical and physical character of the soil--in developing the latent mineral plant-food, and in decomposing and rendering available organic matter, and in forming compounds which attract ammonia from the atmosphere. It may be that we can purchase this ammonia and other plant-food cheaper than we can get it by using lime. It depends a good deal on the nature and composition of the soil. At present, this question can not be definitely settled, except by actual trial on the farm. In England, where lime was formerly used in large quant.i.ties, the tendency for some time has been towards a more liberal and direct use of ammonia and phosphates in manures, rather than to develop them out of the soil by the use of lime. A judicious combination of the two systems will probably be found the most profitable.

Making composts with old sods, lime, and barn-yard manure, is a time-honored practice in Europe. I have seen excellent results from the application of such a compost on meadow-land. The usual plan is, to select an old hedge-row or headland, which has lain waste for many years. Plow it up, and cart the soil, sods, etc., into a long, narrow heap. Mix lime with it, and let it lie six months or a year. Then turn it, and as soon as it is fine and mellow, draw it on to the land. I have a.s.sisted at making many a heap of this kind, but do not recollect the proportion of lime used; in fact, I question if we had any definite rule. If we wanted to use lime on the land, we put more in the heap; if not, less. The manure was usually put in when the heap was turned.

Dr. Vlcker a.n.a.lyzed the dry earth used in the closets at the prison in Wakefield, England. He found that: Phosphoric Nitrogen. Acid.

10 tons of dry earth before using contained 63 lbs. 36 lbs.

10 tons of dry earth after being used once contained 74 " 50 "

10 tons of dry earth after being used twice contained 84 " 88 "

10 tons of dry earth after being used thrice contained 102 " 102 "

After looking at the above figures, the Deacon remarked: "You say 10 tons of dry earth before being used in the closet contained 62 lbs. of nitrogen. How much nitrogen does 10 tons of barn-yard manure contain?"

"That depends a good deal on what food the animals eat. Ten tons of average fresh manure would contain about 80 lbs. of nitrogen."

"Great are the mysteries of chemistry!" exclaimed the Deacon. "Ten tons of dry earth contain almost as much nitrogen as 10 tons of barn-yard manure, and yet you think that nitrogen is the most valuable thing in manure. What shall we be told next?"

"You will be told, Deacon, that the nitrogen in the soil is in such a form that the plants can take up only a small portion of it. But if you will plow such land in the fall, and expose it to the disintegrating effects of the frost, and plow it again in the spring, and let the sun and air act upon it, more or less of the organic matter in the soil will be decomposed, and the nitrogen rendered soluble. And then if you sow this land to wheat after a good summer-fallow, you will stand a chance of having a great crop."

This dry earth which Dr. Vlcker a.n.a.lyzed appeared, he says, "to be ordinary garden soil, containing a considerable portion of clay." After it had been pa.s.sed once through the closet, one ton of it was spread on an acre of gra.s.s-land, which produced 2 tons 8 cwt. of hay. In a second experiment, one ton, once pa.s.sed through the closet, produced 2 tons 7 cwt. of hay per acre. We are not told how much hay the land produced without any dressing at all. Still we may infer that this top-dressing did considerable good. Of one thing, however, there can be no doubt.

This one ton of earth manure contained only 1 lb. more nitrogen and 1 lb. more phosphoric acid than a ton of the dry earth itself. Why then did it prove so valuable as a top-dressing for gra.s.s? I will not say that it was due solely to the decomposition of the nitrogenous matter and other plant-food in the earth, caused by the working over and sifting and exposure to the air, and to the action of the night-soil.

Still it would seem that, so far as the beneficial effect was due to the supply of plant-food, we must attribute it to the earth itself rather than to the small amount of night-soil which it contained.

It is a very common thing in England, as I have said before, for farmers to make a compost of the sods and earth from an old hedge-row, ditch, or fence, and mix with it some lime or barn-yard manure. Then, after turning it once or twice, and allowing it to remain in the heap for a few months, to spread it on meadow-land. I have seen great benefit apparently derived from such a top-dressing. The young gra.s.s in the spring a.s.sumed a rich, dark green color. I have observed the same effect where coal-ashes were spread on gra.s.s-land; and I have thought that the apparent benefit was due largely to the material acting as a kind of mulch, rather than to its supplying plant-food to the gra.s.s.

I doubt very much whether we can afford to make such a compost of earth with lime, ashes, or manure in this country. But I feel sure that those of us having rich clay land containing, in an inert form, as much nitrogen and phosphoric acid as Dr. Vlcker found in the soil to be used in the earth-closet at Wakefield, can well afford to stir it freely, and expose it to the disintegrating and decomposing action of the atmosphere.

An acre of dry soil six inches deep weighs about 1,000 tons; and consequently an acre of such soil as we are talking about would contain 6,200 lbs. of nitrogen, and 3,600 lbs. of phosphoric acid. In other words, it contains to the depth of only six inches as much nitrogen as would be furnished by 775 tons of common barn-yard manure, and as much phosphoric acid as 900 tons of manure. With such facts as these before us, am I to blame for urging farmers to cultivate their land more thoroughly? I do not know that my land or the Deacon's is as rich as this English soil; but, at any rate, I see no reason why such should not be the case.

CHAPTER XXIX.

MANURES FOR BARLEY.

Messrs. Lawes and Gilbert have published the results of experiments with different manures on barley grown annually on the same land for twenty years in succession. The experiments commenced in 1852.

The soil is of the same general character as that in the field on the same farm where wheat was grown annually for so many years, and of which we have given such a full account. It is what we should call a calcareous clay loam. On my farm, we have what the men used to call "clay spots." These spots vary in size from two acres down to the tenth of an acre. They rarely produced even a fair crop of corn or potatoes, and the barley was seldom worth harvesting. Since I have drained the land and taken special pains to bestow extra care in plowing and working these hard and intractable portions of the fields, the "clay spots" have disappeared, and are now nothing more than good, rather stiff, clay loam, admirably adapted for wheat, barley, and oats, and capable of producing good crops of corn, potatoes, and mangel-wurzels.

The land on which Mr. Lawes' wheat and barley experiments were made is not dissimilar in general character from these "clay spots." If the land was only half-worked, we should call it clay; but being thoroughly cultivated, it is a good clay loam. Mr. Lawes describes it as "a somewhat heavy loam, with a subsoil of raw, yellowish red clay, but resting in its turn upon chalk, which provides good natural drainage."

The part of the field devoted to the experiments was divided into 24 plots, about the fifth of an acre each.