Experiments upon Swedes. 9 



that we shall ever understand the action of complicated manures 

 if we do not carefully study the separate effect of their component 

 parts on vegetation. For this reason one plot was manured 

 with sulphate of ammonia, another with sulphate of lime 

 (gypsum), a third with sulphate of potash, a fourth with chloride 

 of sodium, and, finally, one with nitrate of soda. 



In the next place we have in Plot 17 phosphates chiefly in 

 a soluble condition, and free from organic matter or anything 

 else but sulphate of lime, which is necessarily produced when 

 bone-ash is treated with sulphuric acid. In another plot (No. 18) 

 we have the same materials in conjunction with sulphate of am- 

 monia ; and in No. 20 we have them united with nitrate of soda. 



Then with respect to the form in which the nitrogen is applied in 

 these experiments, I would observe that we find it in farmyard- 

 manure, partly as ready-formed ammonia, partly in the shape of 

 semi-decomposed nitrogenized organic matter. In sulphate of 

 ammonia it exists, of course, as a salt of ammonia. In nitrate of 

 soda we apply nitrogen in the shape of nitric acid. In guano 

 nitrogen exists, partly only in the form of ammoniacal salts, the 

 greater portion of nitrogen being present as uric acid and other 

 organic compounds which readily yield ammonia on decomposi- 

 tion. And, lastly, we have in the turnip-manure all these dif- 

 ferent forms in which nitrogen can be applied to the land 

 combined together with phosphates. 



The results of these experiments, though unsatisfactory in 

 some respects, are nevertheless interesting and suggestive in 

 others, and worthy of some comments : 



Plot 1. Manured with 15 tons of Farmyard-manure per Acre. 



tons. cwts. qrs. Ibs. 



Produce 18 10 2 24 



Increase 3 16 1 20 



Plot 2. Manured with 1 5 tons of Farmyard-manure and 2 cwts. of 

 Superphosphate per Acre. 



tons. cwts. qrs. Ibs. 



Produce 17 63 4 



Increase 2 12 2 



In comparing the weight of roots from these two plots, it 

 would appear that the additional quantity of superphosphate has 

 had rather an injurious than a beneficial effect. This, however, 

 would be against common experience. It is probable that there 

 were more plants on No. 1 than on No. 2. Let us suppose that 

 there were 100 plants more on Plot No. 1, and that each root on 

 an average weighed 2 Ibs. ; on calculating the increase per acre 

 we should obtain nearly 1 ton more on the first plot than on 

 the second. I regret not having counted the number of roots. 



