999 



— _ _j 



THE ROTHAMSTED EXPERIMENTS. 



Mixed 

 manures. 



Effects of 

 the con- 

 sumption 

 of roots on 

 the land. 



Dry matter 

 in grain 

 and straw 

 of barley. 



Essentials 

 for barley- 

 growing. 



As already said, the amount of nitrogen annually applied 

 on the mixed manure plot was, for the continuous crops, 

 somewhat more than one-fourth of that applied for the pre- 

 ceding root-crops in the case of the rotation plots. Under 

 these circumstances, the amounts of dry matter in grain, 

 straw, and total produce, were considerably less in the barley 

 grown in rotation where the roots and leaves of the turnips 

 had been removed than in that grown continuously ; but 

 where in the case of the rotation barley the root-crops had 

 been consumed or spread upon the land, the average yield of 

 dry matter per acre was much more nearly identical under 

 rotation and under continuous cropping; though upon the 

 whole it was more under rotation. The effects on the second 

 crop of the course, of the manurial and other treatment of the 

 first crop, are here, then, further illustrated. Lastly, it is to 

 be observed that a larger proportion of the total dry matter' 

 of the crop is, on the average, accumulated in the straw which 

 is generally retained on the farm, than in the grain which is, 

 as a rule, exported from it. 



Thus, both the actual and the comparative results clearly 

 show, that the successful growth of the barley was directly 

 dependent on the supplies within the soil, and that the object 

 may be gained, either in a properly manured rotation, or by 

 the direct application of suitable manures, including a liberal 

 supply of nitrogen for the immediate crop. Having regard to 

 the general economy of the farm, the former plan is as a rule 

 the most advantageous ; though, owing to the success with 

 which the crop can be grown by direct artificial manures, 

 such manures are often used as supplements ; or, sometimes, 

 a barley crop is taken after another cereal, by the aid of arti- 

 ficial manures alone. 



The Dry Matter in the Leguminous Crops. — The third divi- 

 sion of the Table (60) shows the average amounts of dry 

 matter per acre per annum in the corn, straw, and total 

 produce, of the six crops of beans grown in rotation in the 

 eight years ; also the average amounts in the same six years 

 when the crop was grown continuously in another field. Be- 

 low the bean results are given the average amounts per acre 

 per annum in the clover grown in rotation in the remaining 

 two of the eight years ; and there are also given the average 

 amounts over the eight years, in the six crops of beans and 

 two of clover. It will be seen, however, that there is no 

 entry in the line for continuous crops of clover, for the 

 simple reason that, as has been shown in various papers, 

 it was found impossible to grow clover year after year on 

 ordinary arable land. 



The figures show that, meagre as was the average produce 



