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III. Composition of Rotten Leaves 



With the object of determining the difference in the composition of 

 fresh fallen leaves and well rotten ones, samples were taken from beds 

 of well rotten leaves in the spots where fallen leaves were collected. 



Composition of Rotten Leaves 



According to the above table, well rotten leaves are richer in 

 nitrogenous content than fresh fallen leaves. Since well rotten leaves 

 of Akamatsu and Kunugi contain 1.5% of nitrogen in round numbers, 

 they both have a certain manurial value owing to their nitrogenous 

 content. Rotten leaves contain a larger quantities of ash which is 

 due to the fact that organic matter suffers decomposition and decreases 

 in quantity while the loss of mineral matter through rain is relatively 

 small and the composition of leaves thus approaches the surface soil. 

 Compared with freshly collected leaves, the silica, magnesia and oxide of 

 iron contained in the ash of well rotten leaves are remarkebly large in 

 quantity. Phosphoric acid, potash and lime are, however, gradually washed 

 away and decrease with the lapse of years. Still, rotten leaves, of course, 

 always show a far richer content of these last mentioned ingredients than 

 ordinary surface soil. 



The fallen leaves of broad-leaved trees decompose readily while 

 those of conifers are hard to rot owing to the rich content of resin and 

 their strong fibres. Large heaps of coniferous leaves often give rise to 

 humic acid and other objectionable organic compounds doing thereby 

 great harm to growing plants. 



