CHAPTER X 



EXPERIMENTS UPON CROPS GROWN IN ROTATION, AGDELL 



FIELD 

 I. The Unmanured Plots. 

 II. Effect of the Manures. 



III. The Effect of the Growth of Clover or Beans on the succeeding Crops. 



IV. Effect of Manorial Residues on subsequent Crops. 

 V. Gain or loss of Manurial Constituents to the Land. 



Practical Conclusions. 

 References. 



The Agdell field, which was put under experiment in the year 

 1848, differs from the other Rothamsted fields in that it is 

 farmed on a four-course rotation of Swedes, barley, clover (or 

 beans) or fallow, and wheat, instead of growing one crop con- 

 tinuously. It is divided into three main plots, one of which (O) 

 has received no manm^e, the second (M) mineral manures only 

 (superphosphate alone in the first nine courses), and the third 

 (C) a complete manure, containing the same minerals, but also 

 nitrogen in the form of rape cake and ammonium-salts. The 

 manures are applied to the Swedes only, the other three crops 

 of each course being grown without manure. Each of the 

 three plots is further subdivided into four, so as to obtain the 

 following comparisons : — (1) Half the plots carry clover or 

 beans as the third crop of the course, and half the plots are 

 bare fallow. This shows the effect of introducing the legu- 

 minous crop into the rotation, as compared with the bare 

 fallow. (2) From half the plots the root crops grown in the 

 first course are carted ; on the other half the roots are eaten on 

 the land by sheep ; or rather, since the land is unsuited to winter 

 folding, the roots are chopped up and ploughed in. This shows 

 the effect on the succeeding crops of barley, etc., of the return 

 of a root crop to the land by folding. 



The Table LXIV. shows the mean results for the last five 

 courses, 1884-1903. 



