Rotation of Crops. 
587 
1847 ; but, for .reasons which have been explained in various 
papers, they have not been continued up to the present time. 
Those with clover were commenced in 1848, and have been 
succeeded on the same land by others with various leguminous 
plants, which are still continued. Then, of the other more im- 
portant series, those on barley were commenced in 1852, and are 
still in progress, the crop of the present year being, therefore, 
the forty-third in succession. Experiments with oats were com- 
menced in 1869, and continued for ten years; and others, on the 
growth of wheat alternated with fallow, but without manure, 
were commenced in 1851, and are still going on, 1894 being, 
therefore, the forty-fourth year. Of the other field experiments, 
those on the mixed herbage of permanent grass-land were 
commenced in 1856, so that ihis year completes the thirty- 
ninth of their continuance. Lastly, the experiments on an 
actual course of rotation were commenced in 1848, and are still 
continued, so that the present is their forty-seventh year. 
In former papers in this Journal, and elsewhere, the influence 
of exhaustion, manures, and variations of season, on the 
amounts of produce, and on the composition, of certain indi- 
vidual and typical crops, when each is grown separately year 
after year on the same land, have been considered. In this way, 
there have been discussed the characteristic requirements and 
results of growth — of various cereal crops, of various root-crops, 
of potatoes, and lastly, of various leguminous crops. Results of 
the experiments on the mixed herbage of grass-land have also 
been given from time to time. 
Our subject on the present occasion is the Rotation of Crops. 
The mere numerical results of the field experiments made at 
Rothamsted on rotation have been recorded in the annual 
“ Memoranda ” ; but no systematic discussion, either of them or 
of the laboratory investigations undertaken in connection with 
them, has hitherto been published ; and although the present 
communication embodies a good deal of detail, and a somewhat 
comprehensive consideration of it, there still remains much 
which could not be included within the limits of this paper. 
The practice of Rotation is admitted to be the foundation of 
the improvements in our own agriculture which have taken place 
during this and a considerable part of the last century. It is of 
great importance, therefore, carefully to consider, both in what the 
practice itself consists, and how its benefits are to be explained. 
If the rotation of crops as followed in our own country, indeed 
over large portions of Europe, were to be defined in the fewest 
possible words, it might be said that it consists in the alternation 
of root- crops, and of leguminous crops, with cereals. In the 
