CHAPTER XXXI
THEORIES VERSUS FACTS
PERCY planned to walk to Blue Mound to take the three-thirty train that Saturday afternoon; but Adelaide's parents both insisted that she would willingly drive to the station, and the grandmother discovered that she needed a certain kind of thread which Adelaide could then also get at the store.
"Certainly," said Adelaide, with some merriment, "I always enjoy our departing guests to the train."
"Very well," replied Percy. "If you must go to get the thread and will permit me to be the coachman, I shall be satisfied, for you will be home early."
"Then we will take the colts and buckboard, and I shall be home in less than twenty minutes after your train leaves the station."
"I think I have missed several days of your beautiful 'Indian
Summer,' because of my trip to the North," Percy remarked to Mr.
West as they sat on the broad veranda waiting for the hour of two
thirty when the colts were to be ready for the drive.
"I wish you might have been with us while Professor Barstow was here," replied Mr. West, "not only because of the mild autumn weather we have had, but also because Professor Barstow has some ideas about questions of soil fertility that are very different from those you hold. He says a young man from Washington gave a lecture at his college down in North Carolina, in which he informed them that the cause of infertility of soils is a poisonous substance excreted by the plant itself, and that this can be overcome by changing from one crop to another because the excrete of one plant, while poisonous to that plant, will not be poisonous to other plants of a different kind. Thus, by rotation of crops, good crops could be grown indefinitely on the same land without the addition of plant food. He said that the soil water alone dissolved plenty of plant food from all soils for the production of good crops, and that the supply of plant food will be permanently maintained, because the plant food contained in the subsoil far below where the roots go is being brought to the surface by the rise of the capillary moisture, and that there is in fact a steady tendency toward an accumulation of plant food in the surface soil. He said that it is never necessary to apply fertilizing material to any soil for the purpose of increasing the supply of plant food in that soil. He admitted that applications of fertilizers sometimes produce increased crop yields, but that the effect was due to the power of the fertilizer to destroy the toxic substances excreted by the plants, and this is really the principal effect of potash, phosphates, and nitrates, and also of farm manure and green manures. Humus, he said, is one of the very best substances for destroying these toxic excrete although they had some other things which were as good or better than any sore of fertilizing materials. He mentioned especially a substance called pyrogallol, which cost $2.00 a pound, and of course it could not be applied on a large scale; but it was as good a fertilizer as anything, although it contains nothing but carbon, oxygen, and hydrogen, which, as you explained to me when you were here before, the plants secure in abundance from air and water. This information had been secured in the laboratories at Washington by growing wheat seedlings in water culture for twenty-day periods."
"I have already heard something of those theories," said Percy, "but I shall be glad to have you tell me more about them. As I understand them, we need only to rotate and cultivate and our lands should always continue to produce bountiful crops. Is that correct?"
"I understand that is the theory," replied Mr. West, "but I know it is not correct for my grandfather used to grow two or three times as much wheat per acre as I can grow, and I rotate much more than he did. In fact I can grow only ten to fifteen bushels of wheat per acre once in ten years, whereas he grew from twenty-five to forty bushels per acre in a five-year rotation; and I don't see that there is any particular connection between the growing of wheat seedlings in small pots or bottles for a few twenty-day periods and the growing of crops in soils during successive seasons. No, I don't take any stock in their theories. I think they are _watered, _or perhaps I should say _hydrated, _in deference to science. But I would like to know about this question of plant food coming up from below. That would be a happy solution of the fertilizer problem."
"It is true," said Percy, "that soluble salts are brought to the surface in the rise of moisture by capillarity in times of partial drouth; and in the arid regions where the small amount of water that falls in rain or snow leaves the soil only by evaporation, because there is never enough to produce underdrainage, the salts tend to accumulate at the surface. The alkali conditions in the arid or semiarid regions of the West are thus produced. But in humid sections where more or less of the rainfall leaves the soil as underdrainage the regular loss by leaching is so much in excess of the rise by capillarity that soils which are not affected by erosion or overflow steadily decrease in fertility even under natural conditions, with no cultivation and no removal of crops. Of course this applies at first only to the mineral plant foods, as phosphorus potassium, magnesium, and calcium. While mineral supplies are abundant in the surface soil, there may be a large acumulation of organic matter and nitrogen, especially because of the growth of wild legumes, which are very numerous and in places very abundant, especially on some of the virgin prairies of the West. However, as the process of leaching proceeds there comes a time when the growth of the native vegetation is limited because of a deficiency in some essential mineral plant food, such as phosphorus, or the limestone completely disappears and soil acidity develops which greatly lessens the growth of the legumes.
"Decomposition of organic matter begins almost as soon as any part of the plant ceases to live, and there is certain to come a time when the rate of decomposition and loss exceeds the rate of fixation and accumulation; and from that time on the organic matter and nitrogen as well as the mineral plant foods continue to decrease in the surface, until finally the natural barrens are developed, such as are found in different sections of the World and in some places even where the rainfall is sufficient for abundant crops."
"Yes, Sir," said Mr. West. "I know that is true. I have visited Tennessee and I know there are some extensive areas there of practically level upland which have always been considered too poor to justify putting under cultivation, and they are called the 'Barrens'."
"I know about those barren lands, too," said Percy. "Our teacher of soil fertility in college told us that a farm is more than a piece of the earth's surface. He said if we only wanted to get a large level tract of upland where the climate is mild and the rainfall abundant and where all sorts of crops do well on good soil, including the wonderful cotton crop which brings a hundred dollars for a thousand pounds, while corn brings forty dollars for a hundred bushels,—well, he said we could go to the Highland Rim of Tennessee where, according to analyses reported in 1897 by the Tennessee Experiment Station, the surface soil of the 'Barrens' contains eighty-seven pounds of phosphorus and the subsoil sixty-one pounds of phosphorus per acre, counting two million pounds of soil in each case. He said, if we didn't like that we might go into the Great Central Basin of Tennessee or the famous Blue Grass Region of Kentucky and find land that is still extremely productive and more valuable than ever, even after a hundred years of cultivation, and buy land containing from three thousand to fifteen thousand pounds of phosphorus per acre."
"I know both of those sections very well," said Mr. West. "But doesn't it seem strange that the scientists at Washington would teach as they do? Why doesn't the plant food accumulate in the surface soil of those barrens? Surely they have been lying there long enough, with no crops whatever removed, so that they ought to have become very rich. I wish I had known about their phosphorus content so I could have told Professor Barstow. He was quite carried away with the Washington theory."
"You ought not for a moment call it the 'Washington' theory," said Percy; "and neither is it promulgated by scientists, but rather by two or three theorists who are upheld by our greatest living optimist. Science, Sir, is a word to be spoken of always with the greatest respect. Of course you know its meaning?"
"Yes, I know it comes from the Latin _scire, _to know."
"Then _science _means _knowledge; _it does not mean theory or hypothesis, but absolute and positive knowledge. Is there any uncertainty as to the instant when the next eclipse will appear? No, none whatever. Science means knowledge, and men are scientists only so far as they have absolute knowledge, and to that extent every farmer is a scientist.
"Nevertheless the erroneous teaching so widely promulgated by the federal Bureau of Soils is undoubtedly a most potent influence against the adoption of systems of positive soil improvement in the United States, because it is disseminated from the position of highest authority. Other peoples have ruined other lands, but in no other country has the powerful factor of government influence ever been used to encourage the farmers to ruin their lands."