The Science of the Soil 



in many cases is that the grower spends his money uselessly and thought- 

 lessly, and his crops are a failure instead of a success. Here and there, 

 where the special manure happens by accident to suit the soil, good 

 results are secured. The grower is delighted. He pins his faith to that 

 particular brand, and uses it exclusively, until at length he finds that he 

 has ruined his soil and lost his money. This system of cultivation is on 

 a par with the methods of a man who seeks to keep himself in good 

 health by the aid of somebody's much-advertised pills, without taking 

 sufficient natural food or exercise. Sooner or later he becomes a physical 

 wreck (like the soil), and the pills (like the chemical manures) no longer 

 perform the miracles in his system they did when first used. 



This view is borne out in a striking manner from the experiments on 

 Wheat at Rothamsted, an account of which has been published by Mr. A. 

 D. Hall in The Book of the Rothamsted Experiments, from which the 

 following figures are taken: 



TABLE SHOWING THE AVERAGE PRODUCE OF GRAIN PER ACRE THE FIRST EIGHT YEARS 

 (1844-51), AND OVER THE SUCCESSIVE TEN-YEAR PERIODS 



From these figures it will be seen that, while the yield per acre from 

 farmyard manure steadily increased, except in one decade (1872-81), from 

 28 bus. of grain per acre to 39'2 bus., in every case of chemical manures 

 except the " treble ammonium salts and minerals " there was a conspicuous 

 and remarkable decline in the yield. All plots show a big drop for the 

 decade 1872-81, "a period of notoriously bad seasons", as Mr. Hall states. 

 A recovery then took place, but it was as marked in the "unmanured" 

 plot, No. 3, as in some of the others. Indeed the unmanured plot re- 

 covered more effectually than did Plots 5, 10, and 11. Comparing the aver- 

 age yields over the period specified, it will be noticed that while farmyard 



manure shows an increase from 28 bus. in 1844 to 39 bus. in 1901, all the 

 VOL. I. 8 



