378 V. KOZAI, M. TOYONAGA AND M. NAGAOKA. 



Secondly, as to the consumption of phosphoric acid by rice, 

 our researches have given the following results : 





Experi- 

 mental 



Phosphoric acid in the 

 dry matter of the whole 

 crop. 



Phosphoric 



acid in 

 the manure. 



Phosphoric 

 acid extracted 

 from the .^oil 

 resp. from soil 





year. 



0 



. ti • 



Grms. 



Grms. 



and manure. 

 Crrms. 



Unmnnured 



1889 



0.240 



0.64 



0 



0-S5 





1890 



0.165 



0.86 



0 



0.53 





189. 



0.180 



o.So 



0 



0.73 



» 



1802 



0.242 



075 



0 



0.6;; 



J) 



1893 



0 159 



0.23 



0 



0 17 





1804 



0.205 



l.IO 



0 



1.02 



Without pho^. acid 



18S9 



0.232 



0.61 



0 



0.52 





1890 



0. 1 65 



088 



0 



0.55 





1891 



0.171 



0 96 



0 



0.89 





1S92 



0.21 1 



0.78 



0 



0.68 





•893 



0.179 



0.39 



0 



0-33 





1S04 



0.201 



1.25 



0 



i.i7 



Complete manure 



1SS9 



0.320 



4.12 



18.36 



403 





1890 



0.206 



2-73 



18.36 



2.40 



)) 



i8qi 



0.220 



2.62 



833 



2-55 





1892 



0.256 



2.42 



8-33 



2 32 





1S93 



0.262 



2.40 



8.33 



234 





1894 



0.275 



2.88 



8.33 



2.80 



The proportions of the phosphoric acid taken up by the plants 

 from the soil of the unmanured plot and the plot without phosphoric 

 acid did not decrease, but increased with the lapse of years. This 

 shows that the rate of the conversion of the difficultly soluble pho.s- 

 phoric constituents of the soil into an assimilable form also in- 

 creases. As stated in a former number of this bulletin^'^ this is 



(1) This Bulletin Vol. I. No. 1 1. 



