4<5 



grain contains about S3 % of the total amount of phosphoric acid in 

 the plant. 



The percentage of potash, in the entire plant, decreases 

 throughout the plant's life, as in the cases of nitrogen and phosphoric 

 acid. A similar variation takes place in the grain and also in the 

 roots. In the leaves and in the stems the percentages of potash 

 fluctuate in a very different manner to those of the nitrogen and 

 phosphoric acid, which latter decrease at successive stages. The 

 highest percentage of potash in the leaves is found in the period 

 between May io th and May 26 th , when the vegetative portions of the 

 rice plant are in a state of vigorous growth ; afterwards the percent- 

 age of potash gradually decreases to the end of the plant's life. In 

 the stems the greatest percentage of potash occurs at an earlier stage 

 than in the case of the leaves, and decreases until the time of 

 heading out, owing to the actual amount of dry matter in the stems 

 increasing more rapidly than potash is stored. On the contrary, in 

 the later part of the plant's life, the potash in the stems increases 

 in percentage ; this is not due to any great increase in the actual 

 amount of potash, but rather to the fact that the dry matter in the 

 stems decreases in amount. As a rule, the stems contain a higher 

 percentage of potash than the leaves at each stage, while it is just 

 the reverse in the case of the nitrogen. 



The actual amount of potash varies in a somewhat similar 

 manner as the nitrogen in the same parts of the rice plant. The 

 leaves, in which a vigorous formation of protein takes place, contain 

 a rather large amount of potash, and the stems store the greatest 

 quantity of potash at any stages of growth. The amonut of potash 

 in the stems increases till the time of heading out, but it does not 

 decrease at maturity as in the case of nitrogen, which shows a re- 

 markable reduction at this stage'. The actual amount of potash in 

 the roots is very small, not more than 2 % of the total quantity of 

 potash in the plant. The potash in the stems migrates into the 



