Talks on Manures.

by Joseph Harris.

INTRODUCTION.

Sir John Bennet Lawes kindly consented to write a Chapter for the new edition of this work. The Deacon, the Doctor, the Squire, Charlie and myself all felt flattered and somewhat bashful at finding ourselves in such distinguished company. I need not say that this new Chapter from the pen of the most eminent English agricultural investigator is worthy of a very careful study. I have read it again and again, and each time with great and renewed interest. I could wish there was more of it. But to the intelligent and well-informed reader this Chapter will be valued not merely for what it contains, but for what it omits. A man who knew less would write more. Sir John goes straight to the mark, and we have here his mature views on one of the most important questions in agricultural science and practice.

Sir John describes a tract of poor land, and tells us that the cheapest method of improving and enriching it is, to keep a large breeding flock of sheep, and feed them American cotton-seed cake. We are pleased to find that this is in accordance with the general teaching of our "Talks," as given in this book several years ago.

When this work was first published, some of my friends expressed surprise that I did not recommend the more extended use of artificial manures. One thing is certain, since that time the use of superphosphate has been greatly on the increase. And it seems clear that its use must be profitable. Where I live, in Western New York, it is sown quite generally on winter wheat, and also on barley and oats in the spring.

On corn and potatoes, its use is not so common. Whether this is because its application to these crops is not so easy, or because it does not produce so marked an increase in the yield per acre, I am unable to say.

Our winter wheat is sown here the first, second, or (rarely) the third week in September. We sow from one and a half to two and a quarter bushels per acre. It is almost invariably sown with a drill. The drill has a fertilizer attachment that distributes the superphosphate at the same time the wheat is sown. The superphosphate is not mixed with the wheat, but it drops into the same tubes with the wheat, and is sown with it in the same drill mark. In this way, the superphosphate is deposited where the roots of the young plants can immediately find it. For barley and oats the same method is adopted.

It will be seen that the cost of sowing superphosphate on these crops is merely nominal. But for corn and potatoes, when planted in hills, the superphosphate must be dropped in the hill by hand, and, as we are almost always hurried at that season of the year, we are impatient at anything which will delay planting even for a day. The boys want to go fishing!

This is, undoubtedly, one reason why superphosphate is not used so generally with us for corn as for wheat, barley, and oats. Another reason may be, that one hundred pounds of corn will not sell for anything like as much as one hundred pounds of wheat, barley, and oats.

We are now buying a very good superphosphate, made from Carolina rock phosphate, for about one and a half cents per pound. We usually drill in about two hundred pounds per acre at a cost of three dollars. Now, if this gives us an increase of five bushels of wheat per acre, worth six dollars, we think it pays. It often does far better than this. Last year the wheat crop of Western New York was the best in a third of a century, which is as far back as I have had anything to do with farming here.

From all I can learn, it is doubtful if the wheat crop of Western New York has ever averaged a larger yield per acre since the land was first cultivated after the removal of the original forest. Something of this is due to better methods of cultivation and tillage, and something, doubtless, to the general use of superphosphate, but much more to the favorable season.

The present year our wheat crop turned out exceedingly poor. Hundreds of acres of wheat were plowed up, and the land resown, and hundreds more would have been plowed up had it not been for the fact that the land was seeded with timothy gra.s.s at the time of sowing the wheat, and with clover in the spring. We do not like to lose our gra.s.s and clover.

Dry weather in the autumn was the real cause of the poor yield of wheat this year. True, we had a very trying winter, and a still more trying spring, followed by dry, cold weather. The season was very backward. We were not able to sow anything in the fields before the first of May, and our wheat ought to have been ready to harvest in July. On the first of May, many of our wheat-fields, especially on clay land, looked as bare as a naked fallow.

There was here and there, a good field of wheat. As a rule, it was on naturally moist land, or after a good summer-fallow, sown early. I know of but one exception. A neighboring nursery firm had a very promising field of wheat, which was sown late. But their land is rich and unusually well worked. It is, in fact, in the very highest condition, and, though sown late, the young plants were enabled to make a good strong growth in the autumn.

In such a dry season, the great point is, to get the seed to germinate, and to furnish sufficient moisture and food to enable the young plants to make a strong, vigorous growth of roots in the autumn. I do not say that two hundred pounds of superphosphate per acre, drilled in with the seed, will always accomplish this object. But it is undoubtedly a great help. It does not furnish the nitrogen which the wheat requires, but if it will stimulate the production of roots in the early autumn, the plants will be much more likely to find a sufficient supply of nitrogen in the soil than plants with fewer and smaller roots.

In a season like the past, therefore, an application of two hundred pounds of superphosphate per acre, costing three dollars, instead of giving an increase of five or six bushels per acre, may give us an increase of fifteen or twenty bushels per acre. That is to say, owing to the dry weather in the autumn, followed by severe weather in the winter, the weak plants on the unmanured land may either be killed out altogether, or injured to such an extent that the crop is hardly worth harvesting, while the wheat where the phosphate was sown may give us almost an average crop.

Sir John B. Lawes has somewhere compared the owner of land to the owner of a coal mine. The owner of the coal digs it and gets it to market in the best way he can. The farmer's coal mine consists of plant food, and the object of the farmer is to get this food into such plants, or such parts of plants, as his customers require. It is hardly worth while for the owner of the coal mine to trouble his head about the exhaustion of the supply of coal. His true plan is to dig it as economically as he can, and get it into market. There is a good deal of coal in the world, and there is a good deal of plant food in the earth. As long as the plant food lies dormant in the soil, it is of no value to man. The object of the farmer is to convert it into products which man and animals require.

Mining for coal is a very simple matter, but how best to get the greatest quant.i.ty of plant food out of the soil, with the least waste and the greatest profit, is a much more complex and difficult task.

Plant food consists of a dozen or more different substances. We have talked about them in the pages of this book, and all I wish to say here is that some of them are much more abundant, and more readily obtained, than others. The three substances most difficult to get at are: nitric acid, phosphoric acid and potash. All these substances are in the soil, but some soils contain much more than others, and their relative proportion varies considerably. The substance which is of the greatest importance, is nitric acid. As a rule, the fertility of a soil is in proportion to the amount of nitric acid which becomes available for the use of plants during the growing season. Many of our soils contain large quant.i.ties of nitrogen, united with carbon, but the plants do not take it up in this form. It has to be converted into nitric acid. Nitric acid consists of seven pounds of nitrogen and twenty pounds of oxygen. It is produced by the combustion of nitrogen. Since these "Talks" were published, several important facts have been discovered in regard to how plants take up nitrogen, and especially in regard to how organic nitrogen is converted into nitric acid. It is brought about through the action of a minute fungoid plant. There are several things necessary for the growth of this plant. We must have some nitrogenous substance, a moderate degree of heat, say from seventy to one hundred and twenty degrees, a moderate amount of moisture, and plenty of oxygen. Shade is also favorable. If too hot or too cold, or too wet or too dry, the growth of the plant is checked, and the formation of nitric acid suspended. The presence of lime, or of some alkali, is also necessary for the growth of this fungus and the production of nitric acid. The nitric acid unites with the lime, and forms nitrate of lime, or with soda to form nitrate of soda, or with potash to form nitrate of potash, or salt-petre. A water-logged soil, by excluding the oxygen, destroys this plant, hence one of the advantages of underdraining. I have said that shade is favorable to the growth of this fungus, and this fact explains and confirms the common idea that shade is manure.

The great object of agriculture is to convert the nitrogen of our soils, or of green crops plowed under, or of manure, into nitric acid, and then to convert this nitric acid into profitable products with as little loss as possible. Nitrogen, or rather nitric acid, is the most costly ingredient in plant food, and unfortunately it is very easily washed out of the soil and lost. Perhaps it is absolutely impossible to entirely prevent all loss from leaching; but it is certainly well worth our while to understand the subject, and to know exactly what we are doing. In a new country, where land is cheap, it may be more profitable to raise as large crops as possible without any regard to the loss of nitric acid.

But this condition of things does not last long, and it very soon becomes desirable to adopt less wasteful processes.

In Lawes and Gilbert's experiments, there is a great loss of nitric acid from drainage. In no case has as much nitrogen been obtained in the increased crop as was applied in the manure. There is always a loss and probably always will be. But we should do all we can to make this loss as small as possible, consistent with the production of profitable crops.

There are many ways of lessening this loss of nitric acid. Our farmers sow superphosphate with their wheat in the autumn, and this stimulates, we think, the growth of roots, which ramify in all directions through the soil. This increased growth of root brings the plant in contact with a larger feeding surface, and enables it to take up more nitric acid from its solution in the soil. Such is also the case during the winter and early spring, when a good deal of water permeates through the soil. The application of superphosphate, unquestionably in many cases, prevents much loss of nitric acid. It does this by giving us a much greater growth of wheat.

I was at Rothamsted in 1879, and witnessed the injurious effect of an excessive rainfall, in washing out of the soil nitrate of soda and salts of ammonia, which were sown with the wheat in the autumn. It was an exceedingly wet season, and the loss of nitrates on all the different plots was very great. But where the nitrates or salts of ammonia were sown in the spring, while the crops were growing, the loss was not nearly so great as when sown in the autumn.

The sight of that wheat field impressed me, as nothing else could, with the importance of guarding against the loss of available nitrogen from leaching, and it has changed my practice in two or three important respects. I realize, as never before, the importance of applying manure to crops, rather than to the land. I mean by this, that the object of applying manure is, not simply to make land rich, but to make crops grow. Manure is a costly and valuable article, and we want to convert it into plants, with as little delay as possible, which will, directly or indirectly, bring in some money.

Our climate is very different from that of England. As a rule, we seldom have enough rain, from the time corn is planted until it is harvested, to more than saturate the ground on our upland soils. This year is an exception. On Sunday night, May 20, 1883, we had a northeast storm which continued three days. During these three days, from three to five inches of rain fell, and for the first time in many years, at this season, my underdrains discharged water to their full capacity. Had nitrate of soda been sown on bare land previous to this rain, much of it would, doubtless, have been lost by leaching. This, however, is an exceptional case. My underdrains usually do not commence to discharge water before the first of December, or continue later than the first of May. To guard against loss of nitrogen by leaching, therefore, we should aim to keep rich land occupied by some crop, during the winter and early spring, and the earlier the crop is sown in the autumn or late summer, the better, so that the roots will the more completely fill the ground and take up all the available nitrogen within their reach. I have said that this idea had modified my own practice. I grow a considerable quant.i.ty of garden vegetables, princ.i.p.ally for seed. It is necessary to make the land very rich. The plan I have adopted to guard against the loss of nitrogen is this: As soon as the land is cleared of any crop, after it is too late to sow turnips, I sow it with rye at the rate of one and a half to two bushels per acre. On this rich land, especially on the moist low land, the rye makes a great growth during our warm autumn weather.

The rye checks the growth of weeds, and furnishes a considerable amount of succulent food for sheep, during the autumn or in the spring. If not needed for food, it can be turned under in the spring for manure. It unquestionably prevents the loss of considerable nitric acid from leaching during the winter and early spring.

Buckwheat, or millet, is sometimes sown on such land for plowing under as manure, but as these crops are killed out by the winter, they cannot prevent the loss of nitric acid during the winter and spring months. It is only on unusually rich land that such precautions are particularly necessary. It has been thought that these experiments of Lawes and Gilbert afford a strong argument against the use of summer-fallows. I do not think so. A summer-fallow, in this country, is usually a piece of land which has been seeded down one, two, and sometimes three years, with red clover. The land is plowed in May or June, and occasionally in July, and is afterwards sown to winter wheat in September. The treatment of the summer-fallow varies in different localities and on different farms.

Sometimes the land is only plowed once. The clover, or sod, is plowed under deep and well, and the after-treatment consists in keeping the surface soil free from weeds, by the frequent use of the harrow, roller, cultivator or gang-plow. In other cases, especially on heavy clay land, the first plowing is done early in the spring, and when the sod is sufficiently rotted, the land is cross-plowed, and afterwards made fine and mellow by the use of the roller, harrow, and cultivator. Just before sowing the wheat, many good, old-fashioned farmers, plow the land again.

But in this section, a summer-fallow, plowed two or three times during the summer, is becoming more and more rare every year.

Those farmers who summer-fallow at all, as a rule, plow their land but once, and content themselves with mere surface cultivation afterwards.

It is undoubtedly true, also, that summer fallows of all kinds are by no means as common as formerly. This fact may be considered an argument against the use of summer-fallowing; but it is not conclusive in my mind. Patient waiting is not a characteristic of the age. We are inclined to take risks. We prefer to sow our land to oats, or barley, and run the chance of getting a good wheat crop after it, rather than to spend several months in cleaning and mellowing the land, simply to grow one crop of wheat.

It has always seemed to me entirely unnecessary to urge farmers not to summer-fallow. We all naturally prefer to see the land occupied by a good paying crop, rather than to spend time, money, and labor, in preparing it to produce a crop twelve or fifteen months afterwards. Yet some of the agricultural editors and many of the agricultural writers, seem to take delight in deriding the old-fashioned summer-fallow. The fact that Lawes and Gilbert in England find that, when land contains considerable nitric acid, the water which percolates through the soil to the underdrains beneath, contains more nitrate of lime when the land is not occupied by a crop, than when the roots of growing plants fill the soil, is deemed positive proof that summer-fallowing is a wasteful practice.

If we summer-fallowed for a spring crop, as I have sometimes done, it is quite probable that there would be a loss of nitrogen. But, as I have said before, it is very seldom that any water pa.s.ses through the soil from the time we commence the summer-fallow until the wheat is sown in the autumn, or for many weeks afterwards. The nitrogen, which is converted into nitric acid by the agency of a good summer-fallow, is no more liable to be washed out of the soil after the field is sown to wheat in the autumn, than if we applied the nitrogen in the form of some readily available manure.

I still believe in summer fallows. If I had my life to live over again, I would certainly summer-fallow more than I have done. I have been an agricultural writer for one-third of a century, and have persistently advocated the more extended use of the summer-fallow. I have nothing to take back, unless it is what I have said in reference to "fall-fallowing." Possibly this practice may result in loss, though I do not think so.

A good summer-fallow, on rather heavy clay land, if the conditions are otherwise favorable, is pretty sure to give us a good crop of wheat, and a good crop of clover and gra.s.s afterwards. Of course, a farmer who has nice, clean sandy soil, will not think of summer-fallowing it. Such soils are easily worked, and it is not a difficult matter to keep them clean without summer-fallowing. Such soils, however, seldom contain a large store of unavailable plant food, and instead of summer-fallowing, we had better manure. On such soils artificial manures are often very profitable, though barn-yard manure, or the droppings of animals feeding on the land, should be the prime basis of all attempts to maintain, or increase, the productiveness of such soils.

Since this book was first published, I do not know of any new facts in regard to the important question of, how best to manage and apply our barn-yard manure, so as to make it more immediately active and available. It is unquestionably true, that the same amount of nitrogen in barn-yard manure, will not produce so great an effect as its theoretical value would indicate. There can be no doubt, however, that the better we feed our animals, and the more carefully we save the liquids, the more valuable and active will be the manure.

The conversion of the inert nitrogen of manures and soils, into nitric acid, as already stated, is now known to be produced by a minute fungus.

I hope it will be found that we can introduce this _bacterium_ into our manure piles, in such a way as to greatly aid the conversion of inert nitrogen into nitrates.

Experiments have been made, and are still continued, at Woburn, under the auspices of the Royal Agricultural Society of England, to ascertain, among other things, whether manure from sheep receiving an allowance of cotton-seed cake is any richer than that from sheep, otherwise fed alike, but having, instead of cotton-seed cake, the same amount of corn meal. We know that such manure contains more nitrogen, and other plant food, than that from the corn meal. But the experiments so far, though they have been continued for several years, do not show any striking superiority of the manure from cotton-seed cake over that from corn meal. I saw the wheat on these differently manured plots in 1879. Dr.

Vlcker and Dr. Gilbert, told me that, one of two plots was dressed with the cotton-seed manure, and the other with the corn meal manure, and they wanted me to say which was the most promising crop. I believe the one I said was the better, was the cotton-seed plot. But the difference was very slight. The truth is that such experiments must be continued for many years before they will prove anything. As I said before, we know that the manure from the cotton-seed cake is richer in nitrogen than that from the corn meal; but we also know that this nitrogen will not produce so great an effect, as a much smaller amount of nitrogen in salts of ammonia, or nitrate of soda.

In going over these experiments, I was struck with the healthy and vigorous appearance of one of the plots of wheat, and asked how it was manured. Dr. Vlcker called out, "clover, Mr. Harris, clover." In England, as in America, it requires very little observation and experience to convince any one of the value of clover. After what I have said, and what the Deacon, the Doctor, Charley and the Squire have said, in the pages of this book, I hope no one will think that I do not appreciate the great value of red clover as a means of enriching our land. Dr. Vlcker evidently thought I was skeptical on this point. I am not. I have great faith in the benefits to be derived from the growth of clover. But I do not think it originates fertility; it does not get nitrogen from the atmosphere. Or at any rate, we have no evidence of it.

The facts are all the other way. We have discussed this question at considerable length in the pages of this book, and it is not necessary to say more on the subject. I would, however, particularly urge farmers, especially those who are using phosphates freely, to grow as much clover as possible, and feed it out on the farm, or plow it under for manure.

The question is frequently asked, whether the use of phosphates will ultimately impoverish our farms. It may, or it may not. It depends on our general management. Theoretically, the use of a manure furnishing only one element of plant food, if it increases the growth of crops which are sold from the farm, must have a tendency to impoverish the land of the other elements of plant food. In other words, the use of superphosphate furnishing only, or princ.i.p.ally, phosphoric acid, lime and sulphuric acid, must have a tendency to impoverish the soil of nitrogen and potash. Practically, however, it need do nothing of the kind. If the land is well cultivated, and if our low, rich, alluvial portions of the farm are drained, and if the hay, gra.s.s, clover, straw and fodder crops are retained, the more phosphates we use, the richer and more productive will the farm become. And I think it is a fact, that the farmers who use the most phosphates, are the very men who take the greatest pains to drain their land, cultivate it thoroughly, and make the most manure. It follows, therefore, that the use of phosphates is a national benefit.

Some of our railroad managers take this view of the subject. They carry superphosphate at a low rate, knowing that its use will increase the freight the other way. In other words, they bring a ton of superphosphate from the seaboard, knowing that its use will give them many tons of freight of produce, from the interior to the seaboard. It is not an uncommon thing for two hundred pounds of superphosphate, to give an increase of five tons of turnips per acre. Or, so to speak, the railroad that brings one ton of superphosphate from the seaboard, might, as the result of its use, have fifty tons of freight to carry back again. This is perhaps an exceptionably favorable instance, but it ill.u.s.trates the principle. Years ago, before the abolition of tolls on the English turnpike roads, carriages loaded with lime, and all other substances intended for manure, were allowed to go free. And our railroads will find it to their interest to transport manures of all kinds, at a merely nominal rate.

Many people will be surprised at the recommendation of Sir John B.

Lawes, not to waste time and money in cleaning poor land, before seeding it down to gra.s.s. He thinks that if the land is made rich, the superior gra.s.ses overgrow the bad gra.s.ses and weeds. I have no doubt he is right in this, though the principle may be pushed to an extreme. Our climate, in this country, is so favorable for killing weeds, that the plow and the cultivator will probably be a more economical means of making our land clean, than the liberal use of expensive manures. It depends, doubtless, on the land and on circ.u.mstances. It is well to know that manure on gra.s.s land, will so increase the growth of the good gra.s.ses, as to smother the weeds. Near my house was a piece of land that I wanted to make into a lawn. I sowed it with gra.s.s seed, but the weeds smothered it out. I plowed it, and hoed it, and re-seeded it, but still the weeds grew. Mallows came up by the thousand, with other weeds too numerous to mention. It was an eye-sore. We mowed the weeds, but almost despaired of ever making a decent bit of gra.s.s land out of it. It so happened that, one year, we placed the chicken coops on this miserable weedy spot. The hens and chickens were kept there for several weeks. The feed and the droppings made it look more unsightly than ever, but the next spring, as if by magic, the weeds were gone and the land was covered with dark green luxuriant gra.s.s.

In regard to the use of potash as a manure, we have still much to learn.

It would seem that our grain crops will use soda, if they cannot get potash. They much prefer the potash, and will grow much more luxuriantly where, in the soil or manure, in addition to the other elements of plant food, potash is abundant. But the increased growth caused by the potash, is princ.i.p.ally, if not entirely, straw, or leaves and stem. Nature makes a great effort to propagate the species. A plant of wheat or barley, will produce seed if this is possible, even at the expense of the other parts of the plant.

For grain crops, grown for seed, therefore, it would seem to be entirely unprofitable to use potash as a manure. If the soil contains the other elements of plant food, the addition of potash may give us a much more luxuriant growth of leaves and stem, but no more grain or seed. For hay, or gra.s.s or fodder crops, the case is very different, and potash may often be used on these crops to great advantage.

I am inclined to think that considerable nitrate of soda will yet be used in this country for manure. I do not suppose it will pay as a rule, on wheat, corn and other standard grain crops. But the gardener, seed grower, and nurseryman, will find out how to use it with great profit.

Our nurserymen say that they cannot use artificial manures with any advantage. It is undoubtedly true that a dressing of superphosphate, sown on a block of nursery trees, will do little good. It never reaches the roots of the plants. Superphosphate can not be washed down deep into the soil. Nitrate of soda is readily carried down, as deep as the water sinks. For trees, therefore, it would seem desirable to apply the superphosphate before they are planted, and plow it under. And the same is true of potash; but nitrate of soda would be better applied as a top-dressing every year, early in the spring.

The most discouraging fact, in Lawes' and Gilbert's experiments, is the great loss of nitrogen. It would seem that, on an average, during the last forty years, about one-half the nitrogen is washed out of the soil, or otherwise lost. I can not but hope and believe that, at any rate in this country, there is no such loss in practical agriculture. In Lawes'

and Gilbert's experiments on wheat, this grain is grown year after year, on the same land. Forty annual crops have been removed. No clover is sown with the wheat, and great pains are taken to keep the land clean.

The crop is hoed while growing, and the weeds are pulled out by hand.

The best wheat season during the forty years, was the year 1863. The poorest, that of 1879; and it so happened, that after an absence of thirty years, I was at Rothamsted during this poor year of 1879. The first thing that struck me, in looking at the experimental wheat, was the ragged appearance of the crop. My own wheat crop was being cut the day I left home, July 15. Several men and boys were pulling weeds out of the experimental wheat, two weeks later. Had the weeds been suffered to grow, Sir John Bennet Lawes tells us, there would be less loss of nitrogen. The loss of nitrogen in 1863, was about twenty-four pounds per acre, and in 1879 fifty pounds per acre--the amount of available nitrogen, applied in each year, being eighty-seven pounds per acre. As I said before, the wheat in 1879 had to me a ragged look. It was thin on the ground. There were not plants enough to take up and evaporate the large amount of water which fell during the wet season. Such a condition of things rarely occurs in this country. We sow timothy with our winter wheat, in the autumn, and red clover in the spring. After the wheat is harvested, we frequently have a heavy growth of clover in the autumn. In such circ.u.mstances I believe there would be comparatively little loss of nitrogen.