174 



obtained. The three year cropping would give 65 tons of cane which, - 

 together with tops andi fodder (which are burned) would remove from 

 the soil 221 pounds nitrogen. Of this amount, 100 pounds would be 

 furnished by the peas, most of which would go to the plant cane, leav- 

 ing 121 pounds to be supplied by fertilisers in order that the soil may 

 retain the original fertility. It will require over 1,700 pounds of cot- 

 ton seed meal to supply this quantity of nitrogen, or 970 pounds for 

 first year stubble and 730 pounds for the second year stubble. These 

 quantities are usually in excess of practice, because there is a certain 

 amount of nitrogen furnished by the soil every year, and secondly our 

 crops of pease give frequently larger quantities of nitrogen than given 

 above, and, lastly, such tonnage through three years are rarely obtain- 

 ed. However, this will serve as an illustration of the value of nitrogen 

 to the sugar cane crop. 



(2o be continued.) 



SOIL INOCULATION. 



By N. H. J. Miller. 

 Reprinted from Journ. B. Agri. Soc. England^ Vol. VII. 



Whilst the demonstration, some ten years ago, by Hellriegel and 

 Wilfarth of the fixation of elementary nitrogen during the growth of 

 certain plants bearing nodules on their roots, is undoubtedly one of the 

 most interesting and important of recent discoveries — extending our 

 knowledge of the powers exercised by micro-organisms, showing the 

 element nitrogen in an entirely new light, and explaining, to some 

 extent, the exceptional position in agriculture which our leguminous 

 crops have for centuries been known to occupy — it has seemed to some 

 that the amount of labour devoted to the nitrogen question, interesting 

 as are the results which have been obtained, is out of proportion to the 

 practical benefits likely to be derived from it. The question which 

 concerns agriculturists is whether they will be enabled, by growing 

 leguminous crops, to draw upon the practically unlimited store of at- 

 mospheric nitrogen, and thus be less dependent upon the most costly 

 of manures — combined nitrogen, in its different forms. 



To Dr. Salfeld, of Lingen, in Hanover, belongs the credit of being 

 the first to put HellriegeFs discovery to a practical test in the field, 

 his earliest experiments in this direction having been made as far back 

 as 1887. And he has recently collected and published (i) the results of 

 his own and of other experiments made in Germany, Austria and Swe- 

 den, some of which it is proposed in this paper to notice. But, before 

 doing this, a few words on the present position of the nitrogen ques- 

 tion will be useful. 



In the first place, it may be stated that the higher chlorophyllous 

 plants, of whatever order, are totally unable, per se, to assimilate fre© 

 nitrogen. Evidence has, it is true, from time to time been adduced in. 

 support of nitrogen fixation by individual plants, but such results will 



1 A. Salfeld, Die Boden-Impfung zu den Pflanzen rait Schmetterlingsbluten ins* 

 landwirschaf tliehan Bertriebe, Bremen, 1 896. 



