1906.] How LONG DOES LiME LAST IN THE SOIL ? 329 



the cycle of wet seasons culminating in 1879 it was repeatedly 

 found impossible to sow either crop. Eventually the experiments 

 were abandoned and the field laid down to grass, as being unfitted 

 for arable cultivation except in favourable seasons. There was 

 nothing in the situation of this field to account for its wetness, 

 and subsequent examination and analysis of soil and subsoil show 

 that the only difference between this and the other Rothamsted 

 fields lies in its lack of chalk or lime. While the other fields 

 have from 2 to 5 per cent, of chalk in their surface soil, this field 

 must have escaped the chalking process, for it contains prac- 

 tically none. Otherwise, when compared with the Hoos field, 

 where barley is grown every year, its situation is similar, its 

 soil is no heavier, and its subsoil is even a little lighter. 



(2) The insoluble reserves of nitrogenous and potassic 

 material in the soil are brought into action and rendered 

 available for the plant by the presence of lime. The foUov/ing 

 table shows the result of applying in January, 1903, 2,000 lb. 

 per acre of ground quick lime to some of the grass plots at 

 Rothamsted, where there was a good deal of residue from past 

 manuring locked up in the soil : — 





Plot 



7- 



Plot 9. 







Yield with mineral 



manures only. 



Yield with complete artificial 

 manures. 





Unlimed. j 



Limed. 



Unlimed. 



Limed. 



1903 

 1904 

 1905 



1906 



cwt. 



49-5 

 61 -g 



44" 3 

 34"4 



cwt. 



51-9 

 6i-8 

 47-2 

 41 '4 



cwt. 



637 

 36-9 



39-0 



cwt. 

 60 5 

 69-8 

 52*2 

 50 'O 



(3) All the leguminous crops usually cultivated on a farm 

 flourish much better when there is a good supply of lime in the 

 soil. Clover, in particular, is very intolerant of acid soil con- 

 ditions, and is much more subject to clover sickness when lime 

 is deficient. In 1906 alsike clover at Rothamsted was almost a 

 complete failure on a plot where the carbonate of lime had 

 been reduced to about 0*3 per cent., though it was good on an 

 adjoining plot with about 0'5 per cent. 



