V. KOZAI, M. TOVONAGA AND M. XAGAOKA. 



Thus if we supply to the soil i.o kilogrnis. of nitrogen as am- 

 monium salt and 1.3 kilogrms. of phosphoric acid as superphosphate 

 we can get 500 kilogrms. of unhulled rice grain without any 

 waste of the nutriments. This method of calculation may of course 

 be applied to any kind of crops. 



II. SERIES. 



After Effect of unrecovered Phospkoric Acid as SoJium Phosphate. 

 {^Fourth and Fifth Years ^ 



These experiments was performed on those plots to which phos- 

 phoric acid was applied in 1889^^ in various proportions as sodium 

 phosphate, besides much nitrogen as ammonium sulphate and much 

 potash as carbonate. On these plots rice was cultivated in the 

 following years with the supply of nitrogen and potash in the form 

 of the same salts as before in the proportion of 10 kilogrms. of each 

 nutriment per tan. The quantities of phosphoric acid applied in 

 1889 and those left unabsorbed as well as the phosphoric in the 

 fourth year (1892) will be seen from the following table, in which, 

 however, for the sake of comparison, the yields obtained from the 

 plot without phosphoric acid and with a complete manure are also 

 recorded : 



(I) This BuUetin, Vil. I, Xo. 10. 



