586 
Rotation of Crops. 
manure being, as a rule, applied year after year on the same 
plot. But, besides such experiments, what may in a sense be 
called ' complementary series have also been made — on the 
growth of crops in an actual course of rotation, without and 
with different manures. Lastly, others have been conducted on 
the mixed herbage of permanent grass-land, both without and 
with various manures. 
It is obvious that the results of the field experiments with 
individual crops must of themselves throw much light on the 
characteristic requirements of the particular crop under investi- 
gation ; whilst those on the growth of crops in an actual course 
of rotation will serve to confirm and control those obtained with 
the individual crops ; and they will, in their turn, receive elucida- 
tion from the results with the individual crops. Then, again, the 
results of experiments on the application of different manures to 
the mixed herbage of permanent grass-land, which includes, 
among others, members of the botanical families that contribute 
some of the most important of our rotation crops, may, 
independently of their value in reference to the special objects 
for which they were undertaken, be expected to afford interest- 
ing collateral evidence in regard to the requirements of 
individual plants when thus grown in association, instead of 
separately year after year, or in rotation, as in the other series 
of experiments. Obviously, too, the chemical statistics of the 
crops so variously grown, and of the soils of the plots upon 
which they have been grown, must afford very important data 
for further study and elucidation. 
The individual crops which have been grown separately year 
after year on the same land include — wheat, barley, and oats, 
as members of the Order Gramine* ; beans, clover, and other 
plants, of the Order Leguminos* ; turnips of the Crucifer* ; 
sugar-beet and mangel-wurzel of the Chenopodiace* ; and 
potatoes of the Solane*. Then, the experiments on rotation 
include those with members of three different Orders of plants 
— turnips of the Crucifer*, barley and wheat of the Gramme*, 
and clover and beans of the Leguminos*. Lastly, there are the 
experiments on the mixed herbage of permanent grass-land, 
which, besides gramineous and leguminous plants, includes 
numerous species of other natural Orders. 
The first experiments made were those with root-crops, 
which were commenced in June 1843, so that the present year 
(1894) is the fifty-second of their continuance. The second were 
those on wheat, commenced in the autumn of 1843, so that the 
crop just harvested is the fifty-first grown in succession on the 
same land. The experiments with beans were commenced in 
