ROTATION OF CEOPS. 217 



mencing the next course, and to the barley succeeding the 

 roots. 



So far as the roots are concerned, the average results over 

 the eight courses show, both without manure and with super- 

 phosphate alone, that is on the most exhausted plots, that the 

 advantage, if any, is more with the fallow than with the legu- 

 minous plots ; whilst, with the full manure, there is scarcely 

 any difference of result clearly traceable to the treatment of 

 the land in the third year of the preceding courses. Over 

 the last two courses, again, without manure no benefit accrued 

 to the root-crop by the growth of the leguminous crop as 

 compared with fallow. On the superphosphate plots, how- 

 ever, now with potash, soda, and magnesia, as well, and 

 doubtless more leguminous produce accordingly, there were 

 more roots on the leguminous than on the fallow plots ; but, 

 with the full manure, there was practically no difference in 

 the produce of roots on the fallow compared with the legu- 

 minous crop plots. Obviously, the fact that there was not 

 materially less produce of roots where the leguminous crops 

 had been grown and removed, as compared with where the 

 land had been fallow, is of itself evidence of the beneficial 

 rather than exhausting effect of their growth and removal, so 

 far as the requirements of the succeeding crops are concerned. 



Nor is the effect of the growth and removal of a leguminous 

 crop, compared with fallow, very definite on the barley suc- 

 ceeding the manured roots. It is, however, over the eight 

 courses, in favour of the growth of the leguminous crops ; 

 and, though with very small crops, it is, excepting without 

 manure, much more so over the last two courses. 



From the results as a whole it may be concluded that, 

 where the land was the most exhausted, the growth of the 

 leguminous crop was correspondingly limited, and, being at 

 the expense of the little accumulation that there was, its 

 removal further exhausted the immediately available sup- 

 plies ; whilst, where the accumulations were greater, the 

 growth was dependent on a more extended root-development, 

 and therefore greater range of collection ; the luxuriance was 

 much greater, and the surface-soil at any rate gained by an 

 increased amount of highly nitrogenous leguminous crop- 

 residue. It has further been seen, that the effects of the 

 manuring and treatment of the first crop of the course — the 

 turnips — were manifest in the produce of the fourth crop — 

 the wheat ; and also that the effects of fallowing, or of grow- 

 ing and removing a highly nitrogenous crop, in the third year, 

 were clearly traceable on the crop of the fourth year, and 

 to some extent, though in a much less degree, on the subse- 

 quent crops commencing the next course. 



