NA TURE 



5ii 



THURSDAY, FEBRUARY 22, 1912. 



THE STORY OF THE SOIL. 

 The Story of the Soil : from the Basis of Absolute 

 Science and Real Life. By C. G. Hopkins. Pp. 

 350. (London : T. Werner Laurie, n.d.) Price 65. 

 net. 



WHEN Dr. Cyril Hopkins sets out to write a 

 book we know that we are in for something 

 unconventional, but this time he has excelled himself 

 in unconventionality, and has essayed a task that 

 no author has attempted for the last sixty years : to 

 tell the story of the soil in the form of a chronicle 

 that almost amounts to a novel. 



When, in 1852, Hoskyns wrote "Talpa, or the 

 Chronicle of a Clay Farm " — to-day one of the 

 treasures of the agricultural bibliophile — he secured 

 the cooperation of George Cruikshank. But Dr. 

 Hopkins does without any extraneous help, and alone 

 and unaided boldly enters into competition, as he tells 

 us, with popular fiction. The result is remarkable; 

 a clear account is given of the soil in relation to the 

 crop, and the interest of the subject is broadened by 

 skilfully weaving in the threads of a mild novel. 

 It will be interesting to learn whether the farmer 

 reads this book any more readily than he does the 

 ordinary science book that is supposed to appeal to 

 him. 



An agricultural student from Illinois, full of facts 

 and figures, travels about the States in search of 

 a farm. He wants to put into practice some of the 

 ideas he has formed during his college course, and 

 so, instead of seeking for improved land, he looks 

 for a worked-out derelict farm. He first goes south- 

 wards and strikes a Vijginian farm where the produce 

 had fallen during one lifetime from five or six thousand 

 bushels of wheat to five or six hundred, in a district 

 where all the land is at least as impoverished, except- 

 ing only a few dairy farms, on which fertility was 

 maintained at the general expense of the locality by 

 the consumption of hay or grain bought in from 

 neighbouring farms. .\nd this in spite of the fact 

 that most of the farms wore managed by their old 

 owners, a superior type of people, whose chief char- 

 acteristics were "culture, refinement, and poverty." 



The system of management which had brought 

 about this deplorable state of afTairs consisted in 

 ploughing up the run-out pasture land and planting 

 maize, wheat, or oats, followed by a mixture of clover 

 and timothy. The latter is cut for hay for two years, 

 then left for pasture for six or eight years, by which 

 time weeds have crowded out the useful plants ; finally 

 a dressing of farmyard manure is applied, and the 

 land is once more ploughed up for maize. Wheat and 

 cattle are the principal i)roducts sold. This system, 

 we are informed, is in regular use, and leads always 

 to a similar deterioration. Our agricultural student 

 decided not to settle there, but gave some advice that 

 turned out very useful ; he tested the soil with litmus 

 paper, and found that it was acid ; hydrochloric acid 

 also showed the absence of carbonates; it was clear 

 therefore that the soil would produce neither clover 

 XO. 2208, VOL. 88] 



nor lucerne until lime was added, although it could 

 still grow wheat, maize, and timothy. The question 

 whether burnt lime or the less expensive limestone 

 would be the better had been investigated at the 

 Pennsylvania Experiment Station for many years in 

 what is perhaps the most complete set of experiments 

 in the world on this particular problem, and 

 the result shows that finely ground limestone 

 is superior in every way. At most railway stations 

 in Illinois it can be obtained for 1.50 dollars a 

 ton, this low rate being quoted because it is realised 

 that the general prosperity of railway companies and 

 everyone else in Illinois is bound up with the main- 

 tenance of the fertility of the soil. In Virginia, how- 

 ever, no such plan is in operation, so that the cost of 

 the improvement would be considerably higher. But 

 the addition of limestone is only the beginning; the 

 amount of nitrogen in the soil has also to be in- 

 creased, and this can only be done profitably by 

 growing leguminous crops. Since clover only grows 

 with difiiculty, and lucerne not at all, recourse was 

 had to inoculation, not with a bacterial culture, but 

 with soil that had grown lucerne well. Finally, the 

 addition of rock phosphate and an improved rotation 

 raised the fertility of the soil considerably. 



.■\ very different problem was presented by the 

 swamp soils of Illinois, barren in spite of their high 

 content of humus, nitrogen, and phosphorus com- 

 pounds. The Illinois Experiment Station, knowing 

 how to set about the problem, discovered that the 

 supply of potassium constituted the limiting factor; 

 as soon as potassic fertilisers were added the barren 

 soils produced great crops at the cost of about three 

 dollars per acre. A man who had been farming some 

 of the same soil came to see the result, and brought 

 with him his wife and children. 



"As he stood looking first on the corn on the 

 treated and untreated land, and then at his wife and 

 children, he broke down and cried like a child. Later 

 he explained to the superintendent who was showing 

 him the experiments that he had put the best of his 

 life into that kind of land. ' The land looked rich,* 

 he said, ' as rich as any land I ever saw. I bought 

 it and drained it and built my house on a sandy 

 knoll. The first crops were fairlv good, and we hoped 

 for better crops, but instead they grew worse and 

 worse. We raised what we could on a small patch 

 of sandy land, and kept trying to find out what we 

 could grow on this black bogus land. Sometimes I 

 helped the neighbours and got a little money, but my 

 wife and I and my older children have wasted twenty 

 vears on this land. Povertv. |X)verty. always! How 

 was I to know that this single substance which you 

 call potassium was all we needed to make this land 

 productive and valuable?'" 



Thus experience by itself counts for very little; 

 indeed, "experience is a mighty dear teacher, and if 

 we finally learn the lesson it may be too everlasting 

 late for us to apply it." And so, when finally our 

 student settles down in Heart-of-Egypt, Southern 

 Illinois, he has his soil analysed, draws up a rotation 

 and scheme of fertilisers on the most approved priii. 

 ciples, sets them into operation, and— very nearly fails 

 The situation is saved by some advice given by nn 

 old farmer, who has learnt the secret of proper tillage. 

 Moisture, in fact, had been lacking, and the fertiliser 



