"92 The Rothamsted Barley Experiments. 



salts (1 A) alone. Hence, in this, in an agricultural sense, 

 already corn-exhausted soil, the available supply of nitrogen 

 was much more readily exhausted than the available supply 

 of mineral constituents, so far as the requirements for the 

 growth of barley are concerned. 



HAEACTEEISTICS OF THE BEST AND WOEST 

 SEASONS OF THE TWENTY YEAES. 



If space permitted of the presentation here of the tables 

 showing each season's results, it would be necessary to bear 

 in mind that, so far as the influence of season is concerned, 

 the quantity of the produce depends greatly on the amount 

 and the distribution of rain during the growing period ; 

 and the quality (proportion of grain and quality of grain) 

 on a suitable adaptation of temperature. And, so far as the 

 influence of manures is concerned, the quantity (luxuriance) 

 depends greatly on the available supply of nitrogen within 

 the soil, and the quality of the crop (tendency to form seed 

 and to ripen) on the available supply of mineral or ash 

 constituents. 



In no two years during the entire period did one and the 

 same manure yield precisely identical results both as to the 

 quantity and the quality of its produce. Nor have the 

 seasons which have been more or less favourable than the 

 average for one description of manure been equally favour- 

 able or unfavourable for other descriptions. Of the twenty 

 seasons, that of 1854 was upon the whole the most, and that 

 of 1856 was upon the whole the least, productive. The 

 results obtained in each season are stated in Table XXII., 

 in which the same plots are selected as in Table XXI., 

 though, in this case, the uninanured plot has been placed 

 second, and the farmyard-manured first. The description and 

 quantities of manures per acre have already been specified on 

 page 90. 



The remarkable contrasts afforded by this table will 



