MANURING EXPERIMENTS WITH PADDY RICE. 



395 



Now assuming the assimilability of the phosphoric acid of 

 double superphosphate to be lOO, and calculating, on this basis, the 

 relative assimilability of the other forms of phosphoric acid we 

 obtain the following figures ; and we add, for the sake of comparison 

 the relative increase of grains previously mentioned. 



Kind of phofipliatic 

 majiure. 



Rcl.itivL 



■ assiniilaliihty 





in the ist 

 season. j 



in the 1st and 



2nd seasons. 



in the 1st, 2nd, 

 and 3rd 

 seasons. 



i 



■~ CO 



Double superphos- 













phate 



100 



100 



100 



100 



ICQ 



Precipitated phos- 













phate 



104.0 



115.2 



124.2 



1 13.2 



113-2 



Crude bone dust.... 



60.4 



73-0 



76.2 



72.0 



72.0 



Steamed bone dust. 



58.6 



70.6 



76.2 



714 



714 



Thomas phosphate. 



56-9 



72.0 



80.8 



77.8 



79.1 



Peruvian guano.... 



45-3 



50.2 



57-7 



5S-I 



57-2 



Bone ash 



27.4 



33-7 



40.0 



351 



3S-I 



Phosphorite 



7-1 



,3.6 



16.2 



•7-5 



19.1 



Relative increase of Lrrains 



100 



107. 1 



60.2 

 53-5 

 40.5 

 33-5 

 29.1 

 13.0 



108.9 

 734 

 75-7 

 70.6 



54-0 

 324 

 •94 



100 



117.4 



76.4 



79-5 

 7S.1 



58.2 

 37-7 

 -41 



11.65 



77.2 

 78.3 



80.4 



57-5 

 360 

 26.2 



w o 



116.5 

 77.2 

 78.3 

 S4.0 



639 

 36.0 



30-9 



The figures for the relative assimilability of the various forms 

 of phosphoric acid agree very well with those for the relative in- 

 crease of grain. The average of these two series of figures may 

 be taken as basis for the calculation of the quantities of various 

 phosphatic manures to be applied for rice under conditions similar 

 to those tliat obtained in our experiments in regard to soil and 

 climate. 



