INSTITUTE, PUSA, FOR 1916-17 25 



obtained confirm the view expressed by the Indigo Re- 

 search Chemist in a recent paper (Agricultural Journal of 

 India, Indian Science Congress Number, 1917, p. 77) that 

 the soils of Bihar are extraordinarily deficient in available 

 phosphate, and that their practical depletion of such an 

 essential constituent necessitates systematic manuring 

 with superphosphate if the } r ield of crops is to be main- 

 tained. The effect of this deficiency on the quality and yield 

 of other crops is discussed in the paper referred to and its 

 risk of causing malnutrition and endemic disease in cattle 

 and man. It is also suggested that this deficienc}^ is re- 

 lated to the poor quality of native cattle, the low milk 

 yield from buffaloes in Bihar, and nervous diseases such as 

 kumri and defective bone formation in horses in Bengal 

 and Bihar. 



The analyses of rices grown in Bihar published by Mr. 

 Sen in Pusa Bulletin No. 62, show that they are actually 

 seriously deficient in phosphoric acid as compared with 

 rices grown on soils richer in this constituent. 



In connection with the determination of the available 

 phosphate in soils Mr. Sen has carried out a series of ex- 

 periments which show that the addition of calcium car- 

 bonate to a soil giving high values for available phosphate 

 by Dyer's method has a great effect in diminishing the 

 values determined by this method. This is doubtless due 

 to the partial neutralization of the 1 per cent, citric acid 

 used in Dver's method. The low values obtained for avail- 

 able phosphate in Bihar soils is no doubt also due in part 

 to this cause, as these soils contain abnormally large 

 amounts of calcium carbonate, frequently amounting to 30 

 or 40 per cent. It must not be concluded, however, that 

 the citric acid method does not remain an extremely useful 

 diagnostic indication of the needs of such soils. In fact 

 it is well known that manurial recommendations based on 

 Dyer's method give the best results in practice in the case 

 of calcareous soils such as those of Rothamsted, where the 

 relative productivity of the soils agrees closely with the 

 determinations of the available constituents by Dyer's 



