Trees, Fruits and Flowers of Minnesota Part 47

PROF. F. J. ALWAY, DIVISION OF SOILS, UNIVERSITY FARM, ST. PAUL.

I have been asked to speak on "Increasing the Fertility of the Land." To speak on such a subject is sometimes a rather delicate matter because some people consider they have a soil so good that you can't increase its fertility. With some of the prairie soils, when they were first plowed up that wouldn't have been so very far amiss. Take those black prairie soils with the grayish yellow clay subsoil, with an abundance of lime in it, which you find in a large part of the state, including a large part of Hennepin County, and you have as good a soil as you may expect to find anywhere on the earth's surface. But you can't keep a soil up to its full limit of fertility, no matter how good it is, unless you frequently treat it with something.

[Ill.u.s.tration: Prof. F. J. Alway.]

When a soil is well supplied with lime there are three things that are liable to be deficient. If it is not well supplied with lime there may be four, but the bulk of your soils are good enough so far as lime is concerned. Those three are potash, which is abundant and will be abundant 100 years from now, phosphoric acid, or phosphorus, with which our soils are fairly well supplied, and nitrogen, which comes from the vegetable matter. In nitrogen our prairie soils are remarkably rich when first plowed up. The phosphoric acid and the potash you can not lose unless they are taken away in the form of crops, but the nitrogen may be lost without even taking off crops. All you have to do is to cultivate your soil, when part of the nitrogen becomes soluble in water and is carried down by the rain into the water-table unless you have plants growing with roots to take it up; a large part escapes into the air. So when your black prairie soil has been under cultivation for twenty years, as an orchard, usually from one-half to one-third of the original nitrogen has escaped, most of it into the air, only the smaller part being carried off in the crops. That is the one thing that orchardists and horticulturists have to concern themselves about first of all, so far as soil fertility is concerned.

I see that the first of the questions for me to answer deals with that.

"What crop do you consider the best green manure?" There are two kinds of green manures. One is represented by rye. Rye takes up the nitrogen that is in the soil, and when it dies leaves behind what it took out of the soil; the next crop can get this. By plowing under the rye crop you do not increase the amount of nitrogen, the most important element of fertility in the soil.

We have a better green manure than that, better than rye or oats or barley or any of those plants that properly belong to the gra.s.s family; namely, the members of the clover, bean or pea family--all of these plants which are called legumes, which have pods and which have flowers shaped like b.u.t.terflies.

As these grow they take up nitrogen from the air; the bacteria which make their home on the roots of those plants take the nitrogen from the air and give it to their host plants. The plants receive this nitrogen, store it in themselves, and when the crop is plowed under you have a great amount of nitrogen added to the soil. Now, a clover crop of an acre growing from spring until the freeze-up in the fall may take out of the air as much as 120 pounds of nitrogen. One hundred and twenty pounds of nitrogen, bought in the form of commercial fertilizer from Swift & Company, or Northrup, King & Company, would cost you $24.00. The clover has taken that much out of the air. If the crop were pastured off, the greater part of this nitrogen would be returned to the soil; when you plow the clover under still more nitrogen is taken from the air by bacteria that live upon the decaying plant material, and you may have $48.00 worth of nitrogen per acre added to the soil by simply growing clover for one year.

Any kind of green manure crop that bears pods is good. Vetches are good, and soy beans are among the best for orchards. Clover, if you give it time to make a good growth, is as good as anything.

The next question is--"Should apple raisers use commercial fertilizers?"

Now, the apple tree, when it is growing on good soil, makes such a vigorous root development that it is hard to get any commercial fertilizer to help it. On poor soils it, like any other kind of plant, will respond to fertilizers. Some of the eastern experimental stations have been carrying on investigations with commercial fertilizers for a great many years to see whether in apple orchards these will cause an increase in the yield or an improvement in the quality of the fruit. On good soils, even after ten or twelve years' fertilization they have been found to have no effect except in the case of nitrogen, and this can be better supplied in the form of a green manure plowed under than in any other way. That is to say, keep your orchard clean until the last of July or first of August, sow your green manure crop, let it grow until freeze-up and stay there during the winter time. It holds the snow and so affords some winter protection. In the spring plow it under, and you plow under all the nitrogen that the plants had collected the previous year. Then keep your orchard clean during the summer time, until in July or August you again sow the green manure crop.

[Ill.u.s.tration: Applying ground limestone to an acid soil to determine whether liming will be profitable. Half of the field is left unlimed.]

The fertilizers that I get more inquiries about than any others are the phosphates--bone meal, acid phosphate and rock phosphate.

Horticulturists have read that striking results are being obtained with these on certain crops in the eastern and central states, and they want to know whether the same fertilizers will pay here. Some inquire about potash fertilizers. With the latter there is no doubt but that the results we would obtain would, even under ordinary circ.u.mstances, not pay. At the present time potash costs about ten times what it does in times of peace. Sulphate of potash, which ordinarily brings $45.00 per ton, is now quoted at $450. This puts its use out of the question.

The phosphoric acid fertilizers are no higher now than usual. They cost, according to the kind, from $9.50 to $25.00 per ton. Some of them are produced near here--in South St. Paul. With tree crops, apple, plum and pear, we need expect no increased yield from the use of phosphates, unless it be on our very poorest soils. On certain crops, like the bush fruits--the currants and the raspberries, we might get a distinct benefit. I cannot give a definite answer to that. I can tell you what results they have obtained in New York state, what they have obtained in Pennsylvania or Illinois or Maine, but what results we would get in Minnesota we do not know. We can't apply their results to our conditions. The only thing we can do is to carry on such experiments here, and they have not yet been started. That brings me to a third question I have here.

"What experiments are being conducted by the University of Minnesota with orchard and other horticultural crops?" We realized the importance of this matter and plans were prepared. Then, as you know the last legislature was economical. It decided that one of the best places to make a cut would be in the funds for experimental work; when these funds were reduced we not only could start no new experiments but even had to cut off some of the old ones. For that reason these fertilizer experiments have to wait until the next legislature or the one after. I hope the next legislature will make such an appropriation that they may be begun.

Now, for the next question. A man states that he can secure at a very low rate limestone from one of the Minneapolis companies producing crushed limestone for road-making purposes and wants to know whether it will pay him to haul it to his farm. Well, if you do not have any other work for your teams it may pay you. However, if your time is valuable, you had better take some samples of the soil and send them in to the experiment station. Just address them to the Soils Department or Soils Division. Then we can decide whether it is worth while trying some of the limestone. We cannot tell you whether it will pay; we can tell you whether it is likely to pay, or whether it is likely to be a waste of energy, or whether it is so doubtful that you ought to give it a fair trial. On perhaps two-thirds of the fields in Hennepin County it would be a waste of money and energy; on about half of the others, we may say, it is almost certain to be a good investment at a dollar a ton. On the remaining portion we simply can't say. On these, chances are even whether it would pay. No crops are injured by limestone, so you are safe in putting it on. Practically all crops are benefited by it on sour soils and especially the vegetable crops.

The next question is--"Are the black peat or muck soils first cla.s.s? Do they need anything besides drainage?" Some of them, a very few, produce really good crops when they are drained, plowed and brought under ordinary cultivation without fertilization, but only a few. Nearly all of them need commercial fertilizer, and until a bog covered with peat soil has been carefully examined to ascertain the depth of the peat, the difficulty of drainage, and the character of the peat (because peats differ greatly within a few miles of each other) it is unwise to attempt to reclaim it. Within three miles of the experiment station we have three bogs very different in character. One, about half a mile from the buildings, is heavily charged with lime. Another has an exceedingly small quant.i.ty of lime so that profitable crop production of any kind would be out of the question without a heavy application of ground limestone or quicklime. Still another one stands between these two. One of them can be reclaimed without any great expense, but with the one it would be a very expensive matter to fertilize and treat with lime after it had been drained.

Those are the questions that have been given me. Are there any other questions?

Mr. McCall: What is peat lacking in?

Mr. Alway: Practically all peats are lacking in potash. If the peat layer be very shallow, six inches, twelve inches, sometimes even twenty-four inches, the plants are able to get their roots down through the peat and get their potash from the underlying clay or loam. In that case no fertilizer is needed. Some of the peats lack lime, some of them lack lime, potash and phosphoric acid, and some these three and nitrogen also, so that you either have to apply some commercial form of nitrogen or grow legumes as green manures.

Mr. Kellogg: What was the trouble where I couldn't raise strawberries on new wood soil?

Mr. Alway: I couldn't answer that.

Mr. Kellogg: The leaf mold was six or eight inches deep.

Mr. Alway: Was it any deeper than that?

Mr. Kellogg: I don't know, it may have been down a foot, and the leaf mold had been acc.u.mulating there for ages.

Mr. Alway: In some cases the peat is so thoroughly decayed that it looks like leaf mold and it may be a foot or two feet deep.

Mr. Kellogg: This was no peat, it was just wood soil. I could not raise anything--

Mr. Alway: Did the plants grow?

Mr. Kellogg: Yes, the plants grew and wintered well but didn't bear worth a cent.

Mr. Alway: Did they make lots of runners?

Mr. Kellogg: Oh, fairly good, but right over the fence in the next field that had been worked for twenty-five years I got 260 bushels of strawberries to the acre; never had any manure on it.

Mr. Alway: The more leaf mold the more nitrogen; if you have too much nitrogen it may develop the vine and fail to form fruit or seed.

Mr. Ludlow: On heavy black prairie soil, three feet deep, where I am growing eighty bushels of corn to the acre, I want to put in strawberries, and I have a lot of wood ashes, dry wood ashes, not leached ashes, but dry wood ashes. Would it be worth while to put that on or would that overdo the thing? Would it be policy to put that on?

Mr. Alway: It is not likely to do any harm, and it is likely to do some good. Wood ashes contain chiefly lime and potash. The potash will be a distinct benefit. The lime isn't of any particular benefit to this crop on most soils. For strawberries it is slightly harmful on our ordinary soils that are originally well supplied with lime.

Mr. Ludlow: On another piece a ways from that I put out a young orchard, and in order to start the trees well I had covered the ground half an inch deep with wood ashes around those trees. I noticed that the weeds grew there twice as quick as they did when I got away from the wood ashes.

Mr. Alway: There you have the benefit of the potash and the lime. If you put lime in the orchards it will make the clover and most of the other green manure crops grow better, and thus you gain in nitrogen from the lime; you gain in potash as it comes from the wood ashes.

Mr. Brackett: Have you ever found any ground with too much leaf mold on it to grow good strawberries?

Mr. Alway: I have not.

Mr. Brackett: I remember when I broke out my place where I am living now I had a place where the leaves had collected and rotted until I would say there was eight or ten inches of leaf mold. When you went across it you would sink in almost to your shoe tops. On that piece of ground I grew 11,000 quarts of strawberries to the acre in a year, the largest yield I had ever grown on that leaf mold. You can never get too much leaf mold. There must have been something else besides the leaf mold.

Mr. Alway: In case a crop does not give a satisfactory yield it may be due to other things than the soil, and until we eliminate the other possible causes we can't safely blame it to the soil.

Mr. Moyer: What do those black soils in the western part of the state need? They have a whitish deposit on top.

Mr. Alway: Drainage. That is alkali.

Mr. Kochendorfer: I have a ten-year apple orchard that I disked last year and kept it tolerably clean this spring. There were a lot of dandelions sprung up that I mowed down the middle of July, and since then they have grown up again. Will they take nitrogen the same as clover?

Mr. Alway: They won't take any from the air. They will act like so much rye, but when they die and decay nitrogen will be gathered from the air and added to the soil by bacteria that live upon the decaying vegetable matter.

Mr. Kellogg: Did you ever hear of them dying?

Mr. Alway: Dandelions? If they are plowed under.

A Member: Is it practicable to grow soy beans in this soil? Can they be gotten at a reasonable price, and can we mature them here?

Mr. Alway: They mature here without any serious difficulty. There are a great many different varieties. If you order them from a distant seed house you may get a variety that will mature in Louisiana but not in Minnesota.

A Member: How about cowpeas?

Mr. Alway: Cowpeas are disappointing thus far north. In Minnesota they are not nearly as satisfactory as the soy bean. In an unusually warm summer they are satisfactory.