32 



MISC. PUBLICATION 3 6 9, U. S. DEPT. OP AGRICULTURE 



plants grown in two soils of like or nearly the same degree of acidity 

 and of similar texture vary with the calcium content of the soil 

 solution." The data in table 13 illustrate this point. 



Table 13. — Relation between the calcium content of the leaves of the pea plant 1 and 



that of the soil solution 



[Fonder (191)] 



Soil 



pH of 

 soil 



Cain 

 soil solu- 

 tion 



Ca content of leaves after— 



3 weeks 



6 weeks 



8 weeks 



Budding 



Maturity 



Light soils: 



7.40 

 7.35 

 6.25 

 5.10 



5.00 



7.05 



P. p. m. 

 24.55 

 10.60 

 44.70 

 14.62 



30.06 

 19.00 



Percent 



0.259 



.193 



.196 



.185 



.197 

 .193 



Percent 



Percent 



0.260 



.285 



.274 



.255 



.278 

 .336 



Percent 



0.462 



.379 



.292 



.292 



Percent 

 536 



Plainfield 



0.286 

 .359 

 .332 



.384 

 .293 



384 





418 



Hillsdale 



282 



Heavy soils: 



Miami. 



.582 







436 









1 Moisture-free basis. 



Brown (91, 92) analyzed apples grown in different soils in England 

 during two seasons (1926 and 1929). Her results show that the 

 seasonal variations are comparatively small, whereas quite large and 

 significant differences occurred in those fruits grown in different soils. 

 Differences in the calcium and phosphorus contents were particularly 

 noticeable. 



Increasing interest in soil-plant relationships has led to consider- 

 ably more active investigations in this field since 1930 than had been 

 evidenced during any other period. The investigations dming this 

 time will be taken up in their geographical order, so that a clear 

 picture can be had of the work on any group of soils. 



Coleman and Ruprecht {119, 5x) in 1935 analyzed tomatoes, celery, 

 potatoes, oranges, grapefruit, string beans, cabbage, and lettuce grown 

 in different soils in Florida. Their data, included in the compilation 

 in the appendix, show? clearly the influence of soils on the calcium con- 

 tent of the plant. Thus, the calcium content of tomatoes grown in 

 the Bladen soil, a strongly acid soil with a small amount of organic 

 matter, was reported as 0.22 percent, while that of tomatoes grown in 

 the Hernando soil, developed from a phosphatic limestone, was 0.45 

 percent. Similar variations were reported for cabbage and other vege- 

 tables. 



Bryan and Neal (95) in 1936 reported slight variations in the phos- 

 phorus contents of vetch and sorghum grown in three Florida soils in 

 pots. The variations, although consistent in both crops, are not large. 

 Thus, the vetch grown in Norfolk sand contained 0.114 percent of 

 phosphorus, in Norfolk fine sand 0.092 percent, and in Orangeburg 

 fine sand 0.087 percent. 



Bishop (71) grew a number of vegetables in some Alabama soils in 

 the greenhouse, and her analyses, published in 1934, show enormous 

 variations in the calcium and phosphorus contents of the edible por- 

 tions of these crops. Thus, cabbage grown in a Eutaw soil contained 

 0.208 percent of phosphorus, while that grown in a Hartsell soil con- 

 tained only 0.086 percent. In general, the calcium contents of the 

 vegetables were found to be the lowest in those grown in the Norfolk 



