816 EXPERIMENT FTATIO'N' RECORD. [Vol.41 



Cropping experiments were conducted witli three nitrogenous fertilizers called 

 lime nitrogen and cyananiid, but consisting of mixtures of cyanamid, dicyan- 

 diamid, and urea, and with pure dicyandiamid. 



The results obtained corresponded to the content of the fertilizers in urea 

 and dicyandiamid and, allowing for the inhibitory influence of the dicyandiamid, 

 followed the Mitscherlich law of minimum. A small percentage of dicyandiamid 

 did not retard straw and grain yield and, with an increase of nitrogen in the 

 fertilizer, there was a greater relative yield in grain than in straw. This 

 was true for mixtures in which the dicyandiamid represented 35 per cent of 

 the total nitrogen. Pure dicyandiamid did not increase crop growth and is con- 

 sidered possibly as injurious. It is thought that favorable influences attrib- 

 uted to dicyandiamid in previous work may have been due entirely to asso- 

 ciated urea. 



The biological determination of the relative availability of different ni- 

 trogenous organic manures in black cotton soil, F. J. Plymen and D. V. Bal 

 {Agr. Jour. India, IJ, {1919), No. 3, pp. .^i^-^^i).— Studies on the bacterial 

 transformation of six common oil cakes and of au oil-free cake in black cotton 

 soil of the Deccan are reported. 



With the exception of the oil-free cake, karanja {Pongamia glabra) and 

 cotton cakes appeared to be by far the most quickly available, and castor cake 

 was not much inferior to them. Til cake {Sesaumm indicum) was not quite 

 so active, although the nitrogen ultimately nitrified compared favorably with 

 that of other cakes. With the exception of mahua cake {Bassia latifolia), 

 .sarson cake {Brassica. napits) was the slowest so far as uitriflability in black 

 cotton soil is concerned. The nitrogen in mahua cake was neither ammonified 

 nor nitrified to any appreciable extent during a period of eight weeks. 



The value of phosphate manures in India and the possibility of their 

 manufacture on a larger scale, W. A. Davis (Agr. Research Inst. Pusa Bui. 

 81 (1918), pp. 7T-I-2S).— This is a report of a committee made up of a number 

 of reports by individual members and others. Conclusions drawn by the com- 

 mittee from these reports are that not sufficient evidence is aM^ilable to indi- 

 cate definitely 'that any deterioration of the soil arising from depletion of 

 phosphates has occurred generally throughout India, except in the case of the 

 indigo soils of Bihar. 



With reference to the effects of phosphatic fertilization in the different 

 I'roviuces, the reports indicate that " in the indigo districts of Bihar such 

 manuring is plainly beneficial. 



*' In Bengal and Assam, on the old alluvium, there is ample evidence that 

 phosphatic manuring is of value and has given considerable increase with 

 paddy (40 per cent), mustard, and other crops. On the old alluvium, lime is 

 also deficient and is pi'obably necessary to enable phosphates to produce their 

 maximum efilect. On the silt alluvium, evidence is variable and no general 

 conclusion can be drawn. Pending further investigations on the tea garden 

 soils evidence shows that phosphatic manures are of great value. Basic slag 

 and basic superphosphates give the best results. Bone manures and mineral 

 phosphate when applied to the soil have not given noticeable results, except 

 indirectly, through green crops. 



" In the Unitetl Provinces, in the eastern districts on opium soils, it is 

 possible that phosphate manuring may be useful. There is no evidence of 

 phosphate deficiency in other areas. In the Punjab, results appear to indicate 

 that very little benefit is at present found in the use of phosphatic manures 

 in most of the ordinary systems of agriculture adopted in that Province. 



" In Burma, soils of the delta shf>w great variations. In some areas the 

 phosphate supply is ample, in others deficient, lu general, however, it up- 



