ROOT-CROPS. 



25 





Table 5 shows the average amounts of produce — roots, 

 leaves, and total — under the different conditions of manuring 

 over the four years, two with and two without nitrogenous 

 manures. 



TABLE 5.— Swedish Turnips. Results showing the effects of ex- 

 haustion and manures, four seasons, 1849-1852. Manures and 

 produce per acre per annum. 



WITHOUT MINERAL MANURE. 



1 Average of three years only, 1850-52, leaves in 1849 not weighed. 



Compared with the produce of the white turnip, that of 

 the Swedish turnip shows upon the whole rather less root 

 without nitrogenous manure — that is, with the mineral 

 manure alone — owing to the gradual exhaustion of the 

 nitrogen of the soil where none had been applied by manure 

 for a number of years. But, on the other hand, there is, 

 with nitrogenous manures, in two cases out of three, more of 

 the Swedish than of the white turnip root. 



A very important point to notice is that there was, even 

 when there was more root, very much less leaf in the case of 

 the Swedish turnip. Thus, whilst with the highest nitro- 

 genous manure there was, with an average of 10£ tons of the 

 white turnip roots, nearly 6£ tons of leaves, there was with 

 the Swedish turnip, with more than 12 tons of roots, not quite 

 1 ton of leaf. Here, then, the result of growth is that almost 

 the whole of the accumulation is in the food-product, the 

 root, and a very insignificant amount remains in the leaf, 

 most of it simply to become manure again. 



This point will be more clearly illustrated by the results 

 given in Table 6, which gives the leaf to 1000 root, and the 



Swedes 

 and white 

 turnips 

 compared. 



Produce of 

 roots and 

 leaves. 



Accumula- 

 tion in the 

 root. 



Table 6 ex- 

 plained. 



