258 



MATERIALS OF INDIRECT VALUE [chap. 



Surrey, which had been heavily dressed with organic 

 manures for many years previously : — 



Table LXXIX.— Effect of Lime upon Hop Soils. 



Because of the wide fluctuations due to season the 

 yield each year has been calculated on a basis of the 

 limed plot = 100, showing that, on the average, liming 

 has increased the return by 19 per cent. 



It is on soils with a tendency to sourness that 

 liming is of the greatest value, for in such cases dung 

 or any other organic manure only tends to aggravate 

 the evil. This is very well illustrated by the action of 

 lime upon the grass plots at Rothamsted, where 2000 

 lb. per acre of ground lime was applied to half of the 

 plots in January 1903, with the results shown in Table 

 LXXX. ; the yield of the limed half of the plot in each 

 year has been compared with the yield of the unlimed 

 portion taken as 100. 



It will be seen that the increased yield due to 

 liming is most manifest on plots 4/2, 9, and ii/i, 

 where the soil had become acid through the long- 

 continued use of ammonium salts. It should also be 

 noticed that the action of lime is slow, and is more 

 manifest in the third and fourth year after its applica- 

 tion than in the first and second. 



It has already been stated that moulds and other 



