38 



in growth of sugar cane on Plat III can not be correlated watli any 

 cbangcs m ash composition. 



Wliere, however, the growth was very markedly decreased and the 

 plants showed an obvious intolerance for the calcareous soils, as 

 observed with pineapples and rice, the marked decrease in growth 

 was accompanied by marked changes m the ash composition of the 

 plants. The increases in lime in the ash and dry substance of rice 

 and pineapples on the calcareous soils were much greater than the 

 increases in lime induced in the other plants whose growths were not 

 so injuriously affected. The marked decreases in iron in the ash of 

 rice and pineapples were not greater than the decreases in ii-on in 

 some of the other plants whose growths were not depressed. Next 

 to rice and pineapples the largest increase in lime occurred with sweet 

 cassava in Plats III and IV, and on these plats the growth of the 

 plants was markedly depressed. Bush beans, soy beans, sunflowers, 

 radishes, and sugar cane, wliich showed either no decrease in growth 

 or a smaller depression on the calcareous soils than rice, pineapples, 

 and sweet cassava, showed either no increase or a smaller increase 

 in lime in the plant than rice, pineapples, and sweet cassava. 



DISCUSSION OF BESULTS. 



The results reported seem to point to certain general facts. The 

 individuaUty of the various plants with regard to the effect of carbon- 

 ate of lime on theii" growth is very marked, some plants gro%ving 

 equally well on the calcareous and noncalcareous soils and other 

 plants doing veiy poorly on the calcareous soils. There is also an 

 equal individuaUty of the plants in regard to the effect of carbonate 

 of lime on theii' ash composition. This mdividuahty, shown experi- 

 mentally, has an important bearing on the much discussed theories 

 regarding the distribution of plants on calcareous and noncalcareous 

 soils. 



Of the eight plants tested, oidy those plants wliich showed obvious 

 injury and depression in growth from the carbonate of Ume showed 

 a notable increase of Ume in the dry substance of the plant. Some 

 plants, as bush beans, contained no more Ume in the dry substance 

 when grown on the calcareous soil containuig 35 per cent of CaCOj 

 than when grown on the soil that contained no CaCOj, and only 

 1 per cent of CaO present as siUcate. It thus appears that providing 

 there is a certain sufficiency of Ume in the soil it is useless to attempt 

 to increase the Ume content of some plants by Uming.' 



It is also interesting to note that wliile the Ume content of pine- 

 apples increased ^\^th the percentage of CaC'Oj in the sod, the Ume 

 content of sunflowers was greatest on the soil with .5 per cent CaCOg 



1 Consideratile applications of soluble lime salts would probably increase the lime content of the plant 

 oven when there is a sufficiency of lime in (he soil- 



