FERTILIZERS. 129 



observed, however, that in all tliese experiments, other than those 

 made at this Station, the quantities of manure used were the mini- 

 mum or below the minimum of those found in practice; the result can 

 hardly, therefore, be regarded with certainty as fully representing the 

 average." 



On the question of the conservation of nitrogen in barnyard 

 manure, H. Immendorf {Jour. Lan(lw.,43 {1S94), No. l,pp. 69-124). — 

 This is an account of a contiu nation of experiments already noted 

 (E. S. E., 4, p. 9GJ:), undertaken in view of the controversy which the 

 former paper evoked. The literature of the subject is critically 

 reviewed, special attention being- given to reports of Miintz and Girard^ 

 and Holdetieiss, and original investigations are reported under the fol- 

 lowing heads: By what means are the most important losses of nitro- 

 gen occasioned? Where and Avhen in the more common methods of 

 treating manure are the greatest losses of combined nitrogen to be 

 feared? and, How can we reduce as much as possible the loss in the 

 stall and in the dung heap! A report by J. H. Vogel on the action of 

 the gaseous decomposition products of decaying organic substances on 

 phosphoric acid and j)hosphates of lime (p. 125) is also discussed at 

 some length. 



The author concludes that — 



(1) The principal cause of loss of combined nitrogen in the ordinary 

 method of handling manure is to be found in the volatilization of 

 ammonia. The evolution of free nitrogen plays a comparatively insig- 

 nificant role, 



(2) The evolution of ammonia begins as soon as the manure is voided, 

 and is especially rapid in the liquid excrement. A considerable loss 

 of ammonia, as well as of gaseous nitrogen, may also occur after the 

 manure is thrown in the heap. 



(3) Peaty or humus earth may replace with advantage a part at least 

 of the straw generally used as an absorbent. The use of burnt lime or 

 Thomas slag for the purpose of conserving manure should be entirely 

 discarded. Sulj)bate of iron api)ears to possess little value for pre- 

 venting loss of ammonia. It moreover renders the phosphoric acid 

 of the manure insoluble. Gypsum is by no means a perfect ijreserva- 

 tive, large amounts being necessary to prevent loss of ammonia during 

 energetic ammoniacal fermentation. The reason of this is that it is 

 without effect on the process of fermentation, and it goes into solution 

 too slowly to act with the necessary promptness. It is a matter of 

 indifference whether gypsum is used alone or in combination with 

 dicalcium phosphate; but when mixed with water-soluble phosphoric 

 acid, either as free acid or asjnonocalcium phosphate, the volatilization 

 of ammonia is reduced to a marked extent, and the acid reaction of the 

 mixture which results has a decided effect in retarding ammoniacal 

 fermentation. 



'E. S. R., 4, p. 686. 



