312 



EXPEPJMEXTS OX TURXIPS. 



soluble nitrogen, the additional roots grown by its use in a small 

 crop such as that of 1882 are dear. This result is confirmed by 

 Table VIII., ^Yhich shows the result of | cwt. of nitrate of soda 

 with dung. 



(B) Potash.' — Table IX. is arranged on the same principle, to 

 show whether the soil experimented on will repay the addition 

 of potash. The plots put against each other difier only in the 

 presence of 1-J cwt. potash salts, containing approximately 50 lbs. 

 potash, in the manure given to the one and its absence in the 

 manure given to the other. The application pays well on the 

 experimental soil of 1882, and would probably hav^e shown a 

 greater increase with a more favourable season and heavier crop. 



The ground experimented on in 1883, on the other hand, is 

 practically not benefited by potash, and shows the necessity of 

 determining the need of this manure before investing in it 

 largely. Table X. shows that 16 loads of good dung supply 

 enough potash for the growth of the turnip plant. The 

 decrease in 1882 amounts on the average to 6 cwt. per acre ; 

 but in this case it is probably better to consider this as merely 

 an experimental difference, that might have occurred in the 

 averages of two lots of five plots similarly manured, and not as 

 a depression due to the potash salts. It is not probable that 

 the amount of mineral acids set free according to Meyer's 

 hypothesis from J cwt. of potash salts per acre could injure the 

 crop in the presence of a large excess of lime in the surface soil, 



Table IX. 

 Potash without Dung. 



