ROTATION OF CROPS. 207 



roots, during the root-crop period itself, and during the 

 succeeding winter, before the sowing of the barley. There 

 was, therefore, very good preparation for the barley. It will 

 be seen further on that, when grown continuously without 

 manure, both wheat and barley yield more in proportion to 

 their respective averages under ordinary cultivation than 

 does either of the fallow crops — the roots or the leguminous 

 crops. Yet, the produce of barley in rotation without manure Barley in 

 was much in excess of that when it is grown continuously; ^^ 

 the explanation doubtless being, as above referred to, that continu- 

 the crop had been grown after well-cultivated bare fallow 7 . ousiy. 



Next, it is to be observed that, there having been practically 

 no crop of roots without manure, there was no material 

 difference between the yield of the succeeding barley where 

 the roots were carted off or where they were fed on the land. 



Turning now to the produce on the four plots with super- With 

 phosphate alone, it is seen that whilst the average yield of su ^I phos ' 

 barley on the two portions from which the roots had been 

 carted off was under 28 bushels, that on the portions where 

 they had been fed on the land was, in one case more than 

 35|, and in the other 38 bushels. The effect on the one 

 hand of the removal of the larger crop of roots, and on the 

 other of the retention on the land of the greater part of its 

 constituents, is thus very evident. It is further to be re- 

 marked, that the produce of barley where the roots grown by 

 superphosphate had been removed from the land was even 

 less than on the two corresponding portions of the un- 

 manured plot. Thus, there is confirmation of the supposi- 

 tion that the higher crop of barley without manure was due 

 to the previous preparation, and conservation of constituents, 

 by fallow ; and that the lower produce on the superphosphate 

 plot where the roots had been removed was largely due to so 

 much greater exhaustion, especially of the available nitrogen, 

 of the surface soil. 



Next it is seen that, on the plots where the mixed manure Mixed 

 containing nitrogen had been applied for the preceding manure ' 

 turnips, the produce of barley was on a much higher level ; 

 and it was much higher on the portions where the turnips 

 had been fed on the land than on those from which they 

 had been removed. 



It may be observed that the produce, even on the plots Effects of 

 with superphosphate alone, was, where the roots had been fed f^^f 9 ' 

 on the land, about the average of the country at large under roots on 

 ordinary rotation — namely, from 36 to 38 bushels; whilst, land " 

 on the full manured plot, the produce was much more than 

 this — namely, in one case 40f , and in the other 42| bushels, 

 where the roots had been removed; and where they had 



