958 THE COMPLETE GRAZIER. BOOK x. 



carried rabbits or geese." The introduction of turnips into our 

 agricultural rotations is one of the most important improvements of 

 recent times, the growth of the crop constituting an essential link not 

 alone in the four-course, but in various other rotations. 



The swollen root of the turnip or swede, like that of the mangel or 

 beetroot, is really an artificial product, induced by special cultivation, 

 in the absence of which these plants speedily revert to their wild con- 

 dition. They are biennial plants, and the tumid root consists of an 

 abnormal development of the reserve material stored up for the second 

 year's growth of stem, flower, and seed. Though, as grown in 

 rotation, roots are generally regarded as restorative crops, yet they 

 depend for their successful development on the application of large 

 quantities of manure. The value of roots grown in rotation is due, 

 not alone to the opportunities they afford for cleaning the land, but 

 also to the large amount of manure applied, to the considerable residue 

 of this manure left in the soil for future crops, to the large amount of 

 matter at once returned as manure in the leaves, to the large amount of 

 food produced, and to the small amount of the most important mineral 

 constituents of the roots which is retained by the animals consuming 

 them, the rest returning as manure. The idea that root crops by 

 means of their large leaves gained a large amount of nitrogen from the 

 atmosphere was quite fallacious, for no crops are more dependent on a 

 supply of available nitrogen within the soil ; where a good crop of 

 turnips is grown, by superphosphate of lime alone, it is a proof that 

 the soil contained the necessary nitrogen. In a favourable season, 

 indeed, few crops will lower the condition of land so effectually as 

 turnips. 



Experiments made at Eothamsted by Sir John Lawes and Dr. 

 Gilbert have shown that swedes }deld a far larger proportion of root 

 to leaf than is the case with common turnips. Various kinds of 

 manuring were tested, and, whilst with the highest nitrogenous 

 manure there was, with an average crop of 10^ tons per acre of white 

 turnip roots, nearly 6 tons of leaves, there was, in the case of the 

 swedes, with more than 12 tons of roots, not quite one ton of leaf. 

 The result of the growth of the swede, therefore, is that almost the 

 whole of the accumulation is in the food product, the root. 



Other characteristic differences between the common turnip and the 

 swede are worthy of note. Thus the swede gives, under the highest 

 manuring, fully half as much again of dry substance per acre in the root 

 that is, half as much again food produced per acre as the turnip. 

 A quite insignificant amount of matter accumulates and remains, 

 however, in the swede leaf, and the same assertion is true of the 

 nitrogen and total mineral matter. It may, then, be asked why 

 common turnips are ever grown, seeing that swedes possess so many 

 advantages over them. The exigencies of soil, season, and farm 

 economy supply the reasons. On the light soils of Norfolk, for 

 example, which are very favourable to the development of root, and 

 but little for that of leaf, and where the roots can be largely consumed 

 by sheep on the land, without injury to its mechanical condition, the 



