30a HOW CROPS FEED. 



It is seen that the ammonia-salts gave about one-fourth 

 less crop than the nitrate of potash. The potash doubt- 

 less contributed somewhat to this difference. 



The author began some exj^eriraents on this jjoint in 

 1861, which turned out unsatisfactorily on account of the 

 want of liglit in tlie apartment. In a number of these, 

 buckwheat, sown in a weathered feldspatliic sand, was ma- 

 nured with equal quantities of nitrogen, potash, lime, 

 phosjihoric acid, sulphuric acid, and chlorine, the nitrogen 

 being j^resented in one instance in form of nitrate of potash, 

 in the others as an ammonia-salt — sulphate, muriate, phos- 

 phate, or oxalate. 



Although the plants failed to mature, from the cause 

 above mentioned, the experiments plainly indicated the 

 inferiority of ammonia as compared with nitric acid. 



Explanations of this fact are not difficult to suggest. 

 The most reasonable one is, perhaps, to be found in the 

 circumstance that clayey matters (which existed in the 

 soil under consideration) " fix " ammonia, /. e., convert it 

 into a comparatively insoluble compound, so that the 

 plant may not be able to appropriate it all. 



On the other hand, Hellriegel {A)m. d. Landw., VII., 

 53, n. VIII., 119) got a better yield of clover in artificial 

 soil with sulphate of ammonia aiid phosphate of ammonia 

 t*ian with nitrate of ammonia or nitrate of soda, the quan- 

 tity of nitrogen being in all cases the same. 



As Sachs and Knop developed the method of Water- 

 Culture, it was found by the latter that ammonia-saJts did 

 not effectively replace nitrates. The same conclusion was 

 arrived at by Stohmann, in 1861 and 1863 {Henneherg' s 

 Journ., 1862, 1, and 1864, 65), and by Rautenberg and 

 Kuhn, in 1863 (Hermeherg' s Journ., 1864, 107), who ex- 

 perimented with sal-ammoniac, as well as by Birner and 

 Lucanus, in 1864 {Vs. St., VIII., 152), who employed 

 sulphate and phosphate of ammonia. 



The cause of failure lay doubtless in the fiict, first noticed 



