:\IANURING EXPERIMENTS WITH TADDY RICE. 



375 



As to the yields of similarly treated plots, some differences are 

 found in such of the six experimental years, especially with regard 

 to the unmanured plots and those not supplied with phosphoric 

 acid; the produce of 1890 and 1894 being much greater than that of 

 the other years. This difference, though principally due to the con- 

 dition of weather which was exceedingly favourable to the growth 

 of the plants in these two years, may also have been due to the 

 different varieties of the rice used as well as to different degree of 

 development of the young plants in the seed bed at the time of 

 transplantation. In the young plants used for transplantation there 

 were contained for each plot the following quantities of nutriments. 



Dry matter. Nitrogen. Phosphoric acid. Potash. 



Grms. Grms. Grnis. Grms. 



1889 20.55 0.366 0.087 0.192 



1890 62.66 1.774 0.334 0.653 



1891 19.00 0.364 0-073 0.245 



1892 17-47 0.309 0.097 0.15 1 



1893 12.61 0.359 0.061 0.146 



1894 15.53 0.222 0.077 0.175 



The exceedingly large amount of the nutriments in the plants 

 of 1890 also secured a better development, especially on the plots 

 not supplied with these nutriments. 



We have now to consider the degree of exhaustion of soil nutri- 

 ments caused by the continual cultivation of rice. First concerning 

 the consumption of nitrogen we have obtained the following results; 



