866 



SCIENCE 



[N. S. Vol. XXVIII. No. 729 



dening you with one illustration of the 

 hundreds that might be given. 



The soil of the famous Rothamsted Ex- 

 . periment Station is underlain with a bed 

 of calcium carbonate, in the form of chalk, 

 at a depth of eight feet or more. Here, 

 then, is certainly the ideal condition with 

 an immense supply of lime in the lower 

 subsoil, "far below where the roots go," 

 from which there should be an abundance 

 carried up to the surface by capillary mois- 

 ture, in accordance with the theory that 

 "there is a steady tendency toward an 

 accumulation of dissolved mineral matter 

 at the surface.'" 



Now what do we find the truth to be? 

 Is there a steady tendency toward the 

 accumulation of lime in the surface soil at 

 Rothamsted ? 



The existing information is very com- 

 plete on this point. During a period of 

 40 years, from 1865 to 1905, large numbers 

 of analyses have been made of the Rotham- 

 sted soils. During that time, according to 

 Director HalP° and Dr. Miller, from nine 

 different plots on Broadbalk Field there 

 have been the following losses of calcium 

 carbonate per acre per annum from the 

 surface 9 inches: 



Pounds 



From Plot 26 590 



From Plot 3 800 



From Plot 5 878 



From Plot 6 1,174 



From Plot 7 1,010 



From Plot 8 1,174 



From Plot 9 564 



From Plot 10 1,045 



From Plot 11 1,429 



The truth is that instead of an accumu- 

 lation at the surface, there has been a large 

 loss of calcium carbonate from every plot, 

 the total loss in 40 years ranging from 



' Cameron, in " Cyclopedia of American Agricul- 

 ture" (1907), Vol. I., p. 370. 



^"Proceedings of the Royal Society (1905), Vol. 

 77. 



11 tons to 28 tons per acre, and varying 

 with the manures applied and the crops 

 produced. 



Furthermore, from eight different plots 

 on Hoos Field there have been the follow- 

 ing average yearly losses: 



Founds 



From Plot 10 1,185 



From Plot 40 723 



From Plot lA 793 



From Plot 4A 750 



From Plot IN 772 



From Plot iN 554 



From Plot 10 750 



From Plot 7-2 848 



Here, again, every plot reported has sus- 

 tained a large loss, the average being about 

 the same as for Broadbalk Field. The 

 investigations reported also include Agdell 

 Field and Little Hoos Field, both of which 

 have likewise suffered loss in about the 

 same amount as Broadbalk and Hoos. 



Surely with this common knowledge of 

 uncompensated loss by leaching in all nor- 

 mal humid sections, we dare not base our 

 definite plans for systems of permanent 

 agriculture upon a theory that by the rise 

 of capillary water plant food is brought 

 from the lower subsoils sufficient to meet 

 the needs of large crops and to maintain 

 the fertility of the surface soil in all places 

 and for all time; and yet this is the one 

 foundation upon which the teaching of the 

 Bureau of Soils rests concerning permanent 

 supplies of plant food, and is, according to 

 Dr. Cameron, "the most important dis- 

 covery of the Bureau of Soils in recent 

 years. ' ' 



In 1839 the following statement was 

 made in Sir Humphry Davy's "Agricul- 

 tural Chemistry" (p. 343) : 



Some effects attributed to exhaustion of soil 

 may be owing to excretions from roots, injurious 

 to the plants which have yielded them, and yet 

 beneficial to other kinds of plants; in one in- 

 stance acting the part of a poison, in the other 

 of a manure. 



