214 



The Rothamsted Grass Experiments. 



growth were strikingly unfavourable for the herbage, and 

 the period of active growth was itself strikingly adverse, 

 both in its extreme dry ness, and in its coincident high day 

 and low night temperatures. In the case of the excessive, 

 but succulent and immature, growth of 1869, the climatic 

 conditions previous to the period of most active vegetation 

 were obviously very favourable ; but those of the period of 

 active above-ground growth itself were such as would only 

 conduce to great luxuriance provided there were an already 

 forward condition of the herbage. 



The years 1868 and 1874 are also noticed, the former 

 being perhaps the second in order of productiveness 

 and the latter the second in unproductiveness. Table LV. 

 summarises the results in these two years, and may be 

 usefully compared with Table LIV., page 211. 



TABLF. LV.- -PRODUCE OF HAT PER ACRE ON SELECTED PLOTS. 

 AVERAGE OF THE 20 YEARS ; PRODUCE OF 1868, THE TEAR SECOND IN 

 ORDER OF PRODUCTIVENESS ; PRODUCE OF 1874, THE TEAR SECOND IN 

 ORDER OF UNPRODUCTIVENESS ; DIFFERENCE OF EACH FROM THE 

 AVERAGE; AND DIFFERENCE OF THE ONE FROM THE OTHER. 



Another table gives a very full abstract of the meteoro- 

 logical conditions of the two years under notice, and, as 

 before, the relation of the season to the yield of crop is 

 discussed, but the briefest summary must suffice here. 



The season second in order of productiveness was charac- 

 terised by unusually high temperatures throughout the whole 

 period of growth, with a sufficiency of rain up to the end of 

 April, conditions which brought the herbage very early 



