328 Journal of Agriculture. [8 June, 1907. 



XEW SOURCES OF AVAILABLE NITROGEN. 



ir. /. Colcbatch, B.Sc. {Agr.), M.R.C.Y.S. 



Recent European and American researches into the question of im- 

 mediately available nitrate nitrogen have opened up a very extensive field 

 of possibilities in regard to the economic manufacture of nitrogenous 

 fertilisers. The, Australian farmer has happily little experience of soils 

 that respond readily to nitrogenous applications ; in fact, under certain 

 ciicumstances, such practice has resulted in depletion rather than en- 

 hancement of yield. Nevertheless it is unreasonable to argue that the 

 original store of soil nitrogen, even though supplemented by bacterial 

 nitrification of soil constituents and crop residues, will always suffice to 

 promote the maximum growth of vegetation that it is desirable to produce. 



A day must arrive before long when the measure of fertilfty of some of 

 our southern and western soils will be determined by the percentage of 

 available nitrogen as well as of phosphoric acid. The experiments con- 

 ducted by Dr. Howell, late Chemist for Agriculture, have demonstrated 

 the advantages of supplementing the phosphatic dressing with a nitrogenous 

 fertiliser in certain hay-growing districts of the coastal plain and naturallv 

 where potatoes, root, and fodder crops are a feature of the farm practice, 

 still more importance wall attach to this subject. In the northern areas, 

 except where irrigation is carried out, nitrates or indeed any of the nitro'- 

 genous manures are legitimately discounted ; but, viewing Victoria as a 

 whole, and bearing in mind the effects of the Closer Settlement polic\ on 

 the methods of soil culture and farm practice generally, the necessity of 

 keeping ourselves closely in touch with the investigational work and pro- 

 gressive pronouncements of Continental and other authorities becomes 

 dailv more apparent. It is with this purpose in view that the question of 

 available nitrogen, which has been absorbing the energies and interests of 

 many eminent scientists in Europe of recent years, has been revised and 

 amplified in the light of the latest announcements in current literature. 



Nitrogen occurs on the manure-market in at least four distinct forms — 



1. Organic nitrogen — In dried blood, bone dust, &c. 



2. Ammoniacal nitrogen — In sulphate of ammonia. 



3. Cvanamide nitrogen — In lime nitrogen. 



4. Nitrate nitrogen — In nitrate of soda, lime nitrate, &c. 



Of these the last mentioned has the highest commercial and agricul- 

 tural value owing to it being immediately available to plant rootlets. 



The presence of nitrate nitrogen in the soil is due either to bac- 

 terial action or to the application of artificially prepared materials ; in 

 some cases to a combination of these determining factors. The importance 

 of bacterial action on organic, ammoniacal, and nitrate forms of nitrogen 

 . is fullv appreciated, yet the manifold advantages accruing from the 

 utilisation of an immediately soluble form of nitrogenous fertiliser, under 

 favoring conditions, have established beyond argument the wisdom of 

 aiding and supporting the root nodule and nitrifying micro-organisms by 

 the judicious emplovment of a suitable form of a\ailable nitrogen. 



It is remarkable that for over three-quarters of a century the world's 

 supply of nitrate nitrogen has been drawn solely from the South American 

 nitrate of soda fields. During the last few vears, however, the artificial 



