EXPERIMENTS UPON SWEDES, 



IN 1855 I published in this Journal some experiments upon 

 Swedish turnips, grown on a calcareous soil with guano, super- 

 phosphate, bone-dust, night-soil manure, dissolved coprolites, nut- 

 refuse-cake, and several other fertilizers. The object 1 had then 

 in view was to ascertain practically the comparative economic 

 merits of some artificial manures, which at that time were much 

 recommended as turnip manures. The result of these trials proved 

 that whilst one of the fertilizers, namely, the British economical 

 manure, which I regret to say is still sold in many parts of Eng- 

 land, turned out to be a complete failure, and others produced no 

 remunerative crops, superphosphate of lime greatly excelled all 

 other manures employed in the experiments, not even Peruvian 

 guano excepted. The superphosphate used in these experiments 

 was made on our farm by dissolving bone-dust in one-third of oil 

 of vitriol, and consequently contained a considerable quantity of 

 animal nitrogenized matter, which, on decomposition, readily 

 yielded ammonia. On land yielding, when unmanured, 5 tons 

 4 cwt. of roots, topped and tailed, 2/.-worth of home-made super- 

 phosphate gave an increase of 8 tons 8 cwt. 16 Ibs., whilst the 

 same amount of money expended in bone-dust yielded only an 

 increase of 3 tons 12 cwt 



Guano produced 2 tons less of swedes per acre than home- 

 made superphosphate a difference, considering the small crop 

 furnished by the unmanured land, which is considerable. On the 

 other hand, dissolved coprolites gave an increase of 6 tons 8 cwt., 

 or very nearly the same increase as guano alone ; and a mixture of 

 guano and dissolved coprolites an increase of 7 tons 12 cwt. 16 Ibs. 

 The purely mineral superphosphate, made by dissolving copro- 

 lites in acid, thus produced a less favourable effect than the bone- 

 superphosphate, but, when added to guano, dissolved coprolites 



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