100 EXPERIMENTS AVITH SOLUBLE AND INSOLUBLE PHOSPHATES 



of turnip grown on plot 6. Section IV., wliicli received nothing 

 but farmyard manure alone, thus gi\^ng- the excess weight of 

 roots and shaws separately over the weight of that plot. 



The excess of the plot weighed from the general crop, wliich 

 received potash, nitrogen, and phosphates in addition to the 

 farmyard manure was — roots, 10 tons 17 cwt. 16 lbs.; shaws, 

 3 tons 1 cwt. 8 lbs., being nearly double the surplus of any of 

 the plots in either section, and grown at a cost of £2, 4s. lOd. 

 per acre. The source of the nitrogen in the general crop would 

 be principally from Peruvian guano and azote guano. The 

 nitrate of soda and sulphate of ammonia give very even results ; 

 the half and whole quantity of each applied give corresponding 

 results in the increase of crop. This time the azote guano 

 divides the honours with the fish guano, both being again better 

 than the salts of ammonia and nitrate of soda. Coprolites or 

 ground phosphate alone produces barely 13 cwt. of roots more 

 per acre than the farmyard manure ; wliile superphosphate 

 shows a surplus of 38^ cwts., thus again beating its opponent, 

 the insoluble, by a short way. 



Fish guano by itself, added to the farmyard manure, gives 

 the best results for the money in Section IV. ; dissolved bones 

 giving barely half the surplus weight of the fish guano plot. 

 Bone meal has turned out no better than the coprolites, as 

 apphed above farmyard manure, in regard to weight of turnip 

 crop. In glancing at the results of the experiments with these 

 variovis artificial manures, and mixtures of them, as applied 

 above farmyard manure, it is at once apparent that the addition 

 of nitrogen increases the crop to a considerable extent ; while 

 insoluble phosphates do increase it, but only to a very hmited 

 extent, — soluble phosphates increasing the crop still further than 

 insoluljle, but neither of them doing so to an extent that would 

 warrant their economical use above the quantity of dung I have 



