The Rothamsted Wheat Experiments. 



demonstrate, however, that those seasons which were the 

 most favourable for the unmanured, or for the merely 

 mineral-manured plots, were not at all the most favourable 

 for those manured highly with nitrogenous fertilisers that 

 is, for those conditions under which alone large crops could 

 be obtained. Hence, the best season for land in low condi- 

 tion is not the best for land in high condition. 



But, by comparing the increasing or diminishing amounts 

 of produce from year to year, under very different conditions 

 of manuring, a very fair judgment of the relative character of 



TABLE IL AVERAGE ANNUAL PRODUCE (GRAIN AND STRAW) 

 PER ACRE. 



the earlier and later seasons can be formed. From a table 

 indicating the average produce during the first half of the 

 period, during the second half, and during the entire period, 

 it appears that without manure a slightly, though very 

 slightly, increased annual produce of grain and total pro- 

 duce (though not of straw) is marked over the last half 

 as compared with the first half of the twenty years ; with 

 ammonia- salts alone there was a decreased, and with farm- 

 yard manure a very much increased, rate of produce in the 

 later years. Table II. is a portion of the table referred to. 

 Thus, where the crop (plot 3) was simply dependent on 



