CHAPTER XXIV.

THE CHEAPEST MANURE A FARMER CAN USE.

I do not know who first said, “The cheapest manure a farmer can use is--clover-seed,” but the saying has become part of our agricultural literature, and deserves a passing remark.

I have heard good farmers in Western New York say, that if they had a field sown with wheat that they were going to plow the spring after the crop was harvested, they would sow 10 lbs. of clover-seed on the wheat in the spring. They thought that the growth of the clover in the fall, after the wheat was cut, and the growth the next spring, before the land was plowed, would afford manure worth much more than the cost of the clover-seed.

“I do not doubt it,” said the Deacon; “but would it not be better to let the crop grow a few months longer, and then plow it under?”

“But that is not the point,” I remarked; “we sometimes adopt a rotation when Indian-corn follows a crop of wheat. In such a case, good farmers sometimes plow the land in the fall, and again the next spring, and then plant corn. This is one method. But I have known, as I said before, good farmers to seed down the wheat with clover; and the following spring, say the third week in May, plow under the young clover, and plant immediately on the furrow. If the land is warm, and in good condition, you will frequently get clover, by this time, a foot high, and will have two or three tons of succulent vegetation to turn under; and the farmer who first recommended the practice to me, said that the cut-worms were so fond of this green-clover that they did not molest the young corn-plants. I once tried the plan myself, and found it to work well; but since then, I have kept so many pigs and sheep, that clover has been too useful to plow under. But we will not discuss this point at present.

“What I wanted to say is this: Here we have a field in wheat. Half of it (A) we seed down with 12 lbs. of clover-seed per acre; the other half (B) not. The clover-seed and sowing on A, cost, say, $2 per acre. We plow B in the fall; this will cost us about as much as the clover seed sown on A. In the spring, A and B are both plowed and planted to corn. Now, which half of the field will be in the cleanest and best condition, and which will produce the best corn, and the best barley, or oats, afterwards?”

“I vote for A,” said the Deacon.

“I vote for A,” said the Doctor.

“I vote for A,” said the Squire.

“I should think,” modestly suggested Charley, “that it would depend somewhat on the soil,” and Charley is right. On a clean, moderately rich piece of light, sandy soil, I should certainly expect much better corn, and better barley or oats, on A, where the clover was grown, than on B. But if the field was a strong loam, that needed thorough cultivation to get it mellow enough for corn, I am inclined to think that B would come out ahead. At any rate, I am sure that on my own farm, moderately stiff land, if I was going to plant corn after wheat, I should _not_ seed it down with clover. I would plow the wheat stubble immediately after harvest, and harrow and cultivate it to kill the weeds, and then, six weeks or two months later, I would plow it again. I would draw out manure in the winter, pile it up in the field to ferment, and the next spring spread it, and plow it under, and then--

“And then what?” asked the Deacon. --“Why the truth is,” said I, “then I would not plant corn at all. I should either sow the field to barley, or drill in mangel-wurzel or Swede-turnips. But if I _did_ plant corn, I should expect better corn than if I had sown clover with the wheat; and the land, if the corn was well cultivated, would be remarkably clean, and in fine condition; and the next time the land was seeded down with clover, we could reasonably expect a great crop.”

The truth is, that clover-seed is sometimes a very cheap manure, and farmers are in no danger of sowing too much of it. I do not mean sowing too much seed per acre, but they are in no danger of sowing too many acres with clover. On this point, there is no difference of opinion. It is only when we come to explain the action of clover--when we draw deductions from the facts of the case--that we enter a field bristling all over with controversy.

“You have just finished threshing,” said the Deacon, “and for my part, I would rather hear how your wheat turned out, than to listen to any of your chemical talk about nitrogen, phosphoric acid, and potash.”

“The wheat,” said I, “turned out full as well as I expected. Fourteen acres of it was after wheat, and eight acres of it after oats. Both these fields were seeded down with clover last year, but the clover failed, and there was nothing to be done but to risk them again with wheat. The remainder was after barley. In all, there was not quite 40 acres, and we had 954 bushels of Diehl wheat. This is not bad in the circumstances; but I shall not be content until I can average, taking one year with another, 35 to 40 bushels per acre. If the land had been rich enough, there would unquestionably have been 40 bushels per acre this year. That is to say, the _season_ was quite capable of producing this amount; and I think the mechanical condition of the land was also equal to it; all that was needed was sufficient available plant-food in the soil.”

“I can see no reason,” said the Doctor, “why you may not average 40 bushels of wheat per acre in a good season.”

“The field of 14 acres,” said I, “where wheat followed wheat, yielded 23 bushels per acre. Last year it yielded 22 bushels per acre; and so we got in the two years 45 bushels per acre.”

This field has had no manure of any kind for years. In fact, since the land was cleared, 40 or 50 years ago, I presume that all the manure that has been applied would not, in the aggregate, be equal to more than a good crop of clover-hay. The available plant-food required to produce these two crops of wheat came from the soil itself, and from the rain, dews, and atmosphere. The land is now seeded down with clover, and with the aid of a bushel or two of plaster per acre, next spring, it is not improbable that, if mown twice for hay next year, it will yield in the two crops three tons of hay per acre.

Now, three tons of clover-hay contain about 33 lbs. of phosphoric acid, 90 lbs. of potash, and 150 lbs. of nitrogen.

The last crop of wheat, of 22 bushels per acre, and say 1,500 lbs. of straw, would contain:

In the grain. In the straw. In total crop. Phosphoric acid 11½ lbs. 3¾ lbs. 15¼ lbs. Potash 6¾ ” 9¾ ” 16½ ” Nitrogen 23 ” 9½ ” 32½ ”

It seems very unkind in the wheat-plants not to give me more than 22 bushels per acre, when the clover-plants coming after will find phosphoric acid enough for 40 bushels of wheat, and potash and nitrogen enough for nearly 100 bushels of wheat per acre. And these are the three important constituents of plant-food.

Why, then, did I get only 22 bushels of wheat per acre? I got 23 bushels on the same land the year previous, and it is not improbable that if I had sown the same land to wheat again this fall, I should get 12 or 15 bushels per acre again next year. But the clover will find plant-food enough for 40 bushels of wheat.

“There is not much doubt,” said the Deacon, “that you will get a good crop of clover, if you will keep the sheep off of the land this fall. But I do not see what you mean by the clover-plants finding food enough for 40 bushels of wheat, while in point of fact, if you had sown the field again to wheat this fall, you would not, as you say, probably get more than 12 or 15 bushels of wheat.”

“He means this,” said the Doctor. “If he had sown the land to wheat this fall, without manure, he would probably not get over 15 bushels of wheat per acre, and yet you both agree that the land will, in all probability, produce next year, if mown twice, three tons of clover-hay per acre, without any manure.

“Now, if we admit that the clover gets no more nitrogen from the rain and dews, and from the atmosphere, than the wheat will get, then it follows that this soil, which will only produce 15 bushels of wheat per acre, does, in point of fact, contain plant-food enough for 40 bushels of wheat, and the usual proportion of straw.

“The two crops take up from the soil as follows:

Phosphoric acid. Potash. Nitrogen. 15 bushels wheat and straw 10¼ lbs. 11¼ lbs. 22 lbs. 3 tons clover-hay 33 ” 90 ” 150 ”

“These facts and figures,” continued the Doctor, “are worth looking at and thinking about. Why can not the wheat get as much phosphoric acid out of the soil as the clover?”

“Because,” said the Deacon, “the roots of the clover go down deeper into the subsoil than the roots of wheat.”

“That is a very good reason, so far as it goes,” said I, “but does not include all the facts. I have no sort of doubt, that if I had sown this land to wheat, and put on 75 lbs. of nitrogen per acre, I should have got a wheat-crop containing, in grain and straw, 30 lbs. of phosphoric acid. And so the reason I got 15 bushels of wheat per acre, instead of 40 bushels, is not because the roots of wheat do not go deep enough to find sufficient soluble phosphoric acid.”

“Possibly,” said the Doctor, “the nitrogen you apply may render the phosphoric acid in the soil more soluble.”

“That is true,” said I; “and this was the answer Liebig gave to Mr. Lawes. Of which more at some future time. But this answer, like the Deacon’s, does not cover all the facts of the case; for a supply of soluble phosphoric acid would not, in all probability, give me a large crop of wheat. I will give you some facts presently bearing on this point.

“What we want to find out is, why the clover can get so much more phosphoric acid, potash, and nitrogen, than the wheat, from the same soil?”

MORE ABOUT CLOVER.

The Deacon seemed to think the Doctor was going to give a scientific answer to the question. “If the clover _can_ get more nitrogen, phosphoric acid, and potash, from the same soil than wheat,” said he, “why not accept the fact, and act accordingly? You scientific gentlemen want to explain everything, and sometimes make confusion worse confounded. We know that a sheep will grow fat in a pasture where a cow would starve.”

“True,” said the Doctor, “and that is because the cow gathers food with her tongue, and must have the grass long enough for her to get hold of it; while a sheep picks up the grass with her teeth and gums, and, consequently, the sheep can eat the grass down into the very ground.”

“Very well,” said the Deacon; “and how do you know but that the roots of the clover gather up their food sheep-fashion, while the wheat-roots eat like a cow?”

“That is not a very scientific way of putting it,” said the Doctor; “but I am inclined to think the Deacon has the right idea.”

“Perhaps, then,” said I, “we had better let it go at that until we get more light on the subject. We must conclude that the wheat can not get food enough from the soil to yield a maximum crop, not because there is not food enough in the field, but the roots of the wheat are so constituted that they can not gather it up; while clover-roots, foraging in the same soil, can find all they want.”

“Clover,” said the Deacon, “is the scavenger of the farm; like a pig, it gathers up what would otherwise be wasted.”

“Of course, these illustrations,” said the Doctor, “do not give us any clear idea of _how_ the clover-plants take up food. We must recollect that the roots of plants take up their food in solution; and it has just occurred to me that, possibly, Mr. Lawes’ experiments on the amount of water given off by plants during their growth, may throw some light on the subject we are discussing.”

“Mr. Lawes found,” continued the Doctor, “that a wheat-plant, from March 19 to June 28, or 101 days, evaporated through its leaves, etc., 45,713 grains of water; while a clover-plant, standing alongside, and in precisely similar condition, evaporated 55,093 grains. The clover was cut June 28, when in full bloom. The wheat-plant was allowed to grow until ripe, Sept. 7. From June 28 to Sept. 7, or 72 days, the wheat-plant evaporated 67,814 grains.”

“One moment,” said the Deacon; “as I understand, the clover-plant evaporated more water than the wheat-plant, until the 28th of June, but that during the next 71 days, the wheat-plant evaporated more water than it had during the previous 101 days.”

“Yes,” said I, “and if these facts prove nothing else, they at least show that there is a great difference between wheat and clover. I was at Rothamsted when these experiments were made. During the first nine days of the experiment, the clover-plant evaporated 399.6 grains of water; while the wheat-plant, standing alongside, evaporated only 128.7 grains. In other words, the clover-plant evaporated three times as much water as the wheat-plant. During the next 31 days, the wheat-plant evaporated 1,267.8 grains, and the clover-plant 1,643.0 grains; but during the next 27 days, from April 28 to May 25, the wheat-plant evaporated 162.4 grains of water per day, while the clover-plant only evaporated 109.2 grains per day. During the next 34 days, from May 25 to June 28, the wheat-plant evaporated 1,177.4 grains per day, and the clover-plant 1,473.5 grains per day.”

“In June,” said the Deacon, “the clover evaporates ten times as much water per day as it did in May. How much water would an acre of clover evaporate?”

“Let Charley figure it out,” said the Doctor. “Suppose each plant occupies 10 square inches of land; there are 6,272,640 square inches in an acre, and, consequently, there would be 627,264 clover-plants on an acre. Each plant evaporated 1,473.5 grains per day, and there are 7,000 grains in a pound.”

Charley made the calculation, and found that an acre of clover, from May 25 to June 28, evaporated 528,598 lbs. of water, or 15,547 lbs. per day.

A much more accurate way of ascertaining how much water an acre of clover evaporates is afforded us by these experiments. After the plants were cut, they were weighed and analyzed; and it being known exactly how much water each plant had given off during its growth, we have all the facts necessary to tell us just how much a crop of a given weight would evaporate. In brief, it was found that for each pound of dry substance in the wheat-plant, 247.4 lbs. of water had been evaporated; and for each pound in the clover-plant, 269.1 lbs.

An acre of wheat of 15 bushels per acre of grain, and an equal weight of straw, would exhale during the spring and summer 177¾ tons of water, or calculated on 172 days, the duration of the experiment, 2,055 lbs. per day.

An acre of clover that would make two tons of hay, would pass off through its leaves, in 101 days, 430 tons of water, or 8,600 lbs. per day--more than four times as much as the wheat.

These figures show that, from an agricultural point of view, there is a great difference between, wheat and clover; and yet I think the figures do not show the whole of the difference. The clover was cut just at the time when the wheat-plant was entering on its period of most rapid growth and exhalation, and, consequently, the figures given above probably exaggerate the amount of water given off by the wheat during the early part of the season. It is, at any rate, quite clear, and this is all I want to show, that an acre of good clover exhales a much larger amount of water from spring to hay-harvest than an acre of wheat.

“And what,” said the Deacon, who was evidently getting tired of the figures, “does all this prove?”

The figures prove that clover can drink a much greater quantity of water during March, April, May, and June, than wheat; and, consequently, to get the same amount of food, it is not necessary that the clover should have as much nitrogen, phosphoric acid, potash, etc., in the water as the wheat-plant requires. I do not know that I make myself understood.

“You want to show,” said the Deacon, “that the wheat-plant requires richer food than clover.”

Yes, I want to show that, though clover requires _more_ food per day than wheat, yet the clover can drink such a large amount of water, that it is not necessary to make the “sap of the soil” so rich in nitrogen, phosphoric acid, and potash, for clover, as it is for wheat. I think this tells the whole story.

Clover is, or may be, the grandest renovating and enriching crop commonly grown on our farms. It owes its great value, not to any power it may or may not possess of getting nitrogen from the atmosphere, or phosphoric acid and potash from the subsoil, but principally, if not entirely, to the fact that the roots can drink up such a large amount of water, and live and thrive on very weak food.

HOW TO MAKE A FARM RICH BY GROWING CLOVER.

Not by growing the clover, and selling it. Nothing would exhaust the land so rapidly as such a practice. We must either plow under the clover, let it rot on the surface, or pasture it, or use it for soiling, or make it into hay, feed it out to stock, and return the manure to the land. If clover got its nitrogen from the atmosphere, we might sell the clover, and depend on the roots left in the ground, to enrich the soil for the next crop. But if, as I have endeavored to show, clover gets its nitrogen from a weak solution in the soil, it is clear, that though for a year or two we might raise good crops from the plant-food left in the clover-roots, yet we should soon find that growing a crop of clover, and leaving only the roots in the soil, is no way to permanently enrich land.

I do not say that such a practice will “exhaust” the land. Fortunately, while it is an easy matter to impoverish land, we should have to call in the aid of the most advanced agricultural science, before we could “exhaust” land of its plant-food. The free use of Nitrate of Soda, or Sulphate of Ammonia, might enable us to do something in the way of exhausting our farms, but it would reduce our balance at a bank, or send us to the poor-house, before we had fully robbed the land of its plant-food.

To exhaust land, by growing and selling clover, is an agricultural impossibility, for the simple reason that, long before the soil is exhausted, the clover would produce such a poverty-stricken crop, that we should give up the attempt.

We can make our land poor, by growing clover, and selling it; or, we can make our land rich, by growing clover, and feeding it out on the farm. Or, rather, we can make our land rich, by draining it where needed, cultivating it thoroughly, so as to develope the latent plant-food existing in the soil, and then by growing clover to take up and organize this plant-food. This is how to make land rich by growing clover. It is not, in one sense, the clover that makes the land rich; it is the draining and cultivation, that furnishes the food for the clover. The clover takes up this food and concentrates it. The clover does not create the plant-food; it merely saves it. It is the thorough cultivation that enriches the land, not the clover.

“I wish,” writes a distinguished New York gentleman, who has a farm of barren sand, “you would tell us whether it is best to let clover ripen and rot on the surface, or plow it under when in blossom? I have heard that it gave more nitrogen to the land to let it ripen and rot on it, but as I am no chemist, I do not know.”

If, instead of plowing under the clover--say the last of June, it was left to grow a month longer, it is quite possible that the clover-roots and seed would contain more nitrogen than they did a month earlier. It was formerly thought that there was a loss of nitrogen during the ripening process, but the evidence is not altogether conclusive on the point. Still, if I had a piece of sandy land that I wished to enrich by clover, I do not think I should plow it under in June, on the one hand, or let it grow until maturity, and rot down, on the other. I should rather prefer to mow the crop just as it commenced to blossom, and let the clover lie, spread out on the land, as left by the machine. There would, I think, be no loss of fertilizing elements by evaporation, while the clover-hay would act as a mulch, and the second growth of clover would be encouraged by it. Mow this second crop again, about the first week in August. Then, unless it was desirable to continue the process another year, the land might be plowed up in two or three weeks, turning under the two previous crops of clover that are on the surface, together with the green-clover still growing. I believe this would be better than to let the clover exhaust itself by running to seed.