MINERAL COMPOSITION OF CROPS 



29 



was found to be 0.020 percent, as compared with 0.043 percent for 

 the Sagemoor soil, and this difference seems to correlate very well 

 with the sulfur content of the vegetation. 



Table 10. — Mineral composition of alfalfa 1 (average of duplicate experiments 

 grown in pots without fertilizer treatments) 





[Neller (482)] 













Soil 



Yield 



Ash 



N 



K 



Ca 



P 



S 





Gm. 

 31.8 

 25.1 



Percent 

 8.30 



Percent 

 1.64 



2.57 



Percent 

 3.13 

 2.32 



Percent 

 1.38 

 1.92 



Percent 



0.230 



.139 



Percent 

 0.120 





.242 





i 





1 Moisture-free basis. 

















Meinck (406), in studying the relationships between the iodine 

 content of the soil, water, and foods in goitrous regions in Germany, 

 reported in 1927 little correlation between the iodine content of pota- 

 toes and either the total or hydrochloric acid soluble iodine in the 

 soil. Potatoes grown at Schwalbach in a soil having 168 p. p. b. of 

 iodine soluble in acid contained more than three times as much 

 iodine as did potatoes grown at Mammolsheim in a soil having 502 

 p. p. b. of soluble iodine. The total iodine in the soil in both cases 

 was nearly the same. 



The variations in the composition of soybean forage grown in six 

 Michigan soils were determined by Austin (37) in 1928. The plots, 

 located in different parts of the State, were all planted and harvested 

 at the same time, so that the age factor was eliminated. In deter- 

 mining the composition of the plants the entire above-ground portion 

 of the plant was used for analysis. The data obtained on samples 

 from the unfertilized plots are presented in table 11. A study of the 

 data indicates that some of the constituents vary to a marked extent, 

 and that certain trends during the whole season are observable. The 

 calcium content of the plants grown in the Hillsdale soil is without 

 exception higher than the average throughout the season, while that 

 of the plants grown in the Kewanee is below average throughout the 

 season. The average seasonal value for calcium in the plants grown 

 in the Hillsdale is 2.206 percent, as compared with 1.729 percent for 

 that grown in the Kewanee. The magnesium content of the plants 

 grown in the Brookston soil is in some cases nearly double that of 

 plants grown in other soils, and it remains high throughout the 

 season. It is apparent that the plants grown in the Kewanee soil 

 are consistently high in potassium throughout the season as com- 

 pared with those grown in other soils. The plants grown in the 

 Miami are likewise low in phosphorus, while those grown in the 

 Brookston and Coloma soils are consistently above the average in 

 this respect. The differences (0.278 compared with 0.411 and 0.425 

 percent respectively) are important. 



