ROTATION OF CROPS. 203 



The figures in the middle division of the table show that 

 the produce of leaf as well as that of roots was increased by- 

 superphosphate, and that it was still further increased by the 

 mixed manure containing nitrogen. 



The next point is to consider the effects of the other con- Effects of 

 ditions besides those of different manure supply ; that is, the c °^ r Z ny 

 removal of the root-crop, or the ieedmg or the spreading ol it land. 

 upon the land ; also whether, in the third year of each course, 

 a leguminous crop was grown, or the land was fallowed. 



It is seen that, without manure, whether clover or beans 

 were grown, or the land were fallowed, there was even rather 

 less average produce of roots over the eight years where they 

 had been fed on the land, than where they had been carted 

 off; but with such very small crops the differences are im- 

 material, if not accidental. 



On the superphosphate plots, where the produce was much 

 higher, and where there would, therefore, be more loss to the 

 land by removal, the crops were materially better on the fed 

 portions of the plots. 



On the mixed manure plots, on the other hand, with nearly 

 twice as much produce as with superphosphate alone, there 

 would be still greater difference between the condition of the 

 land where the roots were carted off and where they were fed 

 on ; but there was very little difference in the average pro- 

 duce of the root- crop. 



It will be seen further on, that the higher condition of the 

 land where the more highly manured roots were fed upon it 

 had a very marked effect on the succeeding cereal crops, and 

 especially on the immediately succeeding barley. This was 

 the case on both the superphosphate and the mixed manure 

 plots. 



The difference of effect on the average produce of the root- Effects of 

 crop, by fallowing, or by growing beans or clover, in the Mowing 



. r , J „ ,°' J P . . i i t and grow- 



third year of each course is, in the comparable cases, prac- i ng beans 

 tically immaterial under each of the three different conditions a ^ clover - 

 as to manuring. 



Before passing from Table 56 it is to be observed that 

 there was higher average produce over the tenth and eleventh 

 courses with superphosphate and potash, soda, and magnesia, 

 than over the preceding eight courses with superphosphate 

 alone. But, as there was also increase in a greater degree influence 

 with the mixed mineral and nitrogenous manure over the °f season - 

 two than over the eight years, it is obvious that the character 

 of the seasons had a good deal to do with the result. It is 

 noticeable, however, that on the plots with potash, soda, and 

 magnesia, as well as superphosphate, in the two courses, there 

 was a higher produce of roots on the plots where beans or 



