50 MISC. PUBLICATION 3 69, U. S. DEPT. OF AGRICULTURE 



plainly that orchard welfare is not directly affected by soil spray 

 residue accumulations, however long the period of accumulation." 

 Their conclusions, of course, relate only to the fruit of trees and not 

 to any crop such as a legume or cereal that might he planted in the soil. 

 Hurd-Karrer (283) has observed that arsenic injury is inhibited by 

 phosphorus applications to certain soils that do not fix the phosphorus 

 in an unavailable state. 



Stewart and Smith (540) in 1922, using a gravelly bench loam for 

 pot tests, reported enormous increases in the arsenic content of pea, 

 radish, wheat, potato, and bean plants. Disodium arsenate was added 

 to the pots after the plant was fairly well developed. 



McHargue and Shedd (382) studied the effect of manganese, copper, 

 zinc, boron, and arsenic on the growth of oats. Their data, reported 

 in 1930, show the effect of manganese only, for in only one experiment 

 did they use a single element. In the remainder of the tests, manganese 

 was used with copper or with copper and zinc, etc. The manganese 

 content of oat straw was increased from 0.004 to 0.0644 percent, but 

 no other significant change in the composition of the plant was found 

 with manganese fertilization. Coleman and Ruprecht (119) in 1932 

 reported that increases in the manganese content of vegetables grown 

 in Florida soils was obtained when manganese was applied as a fertilizer 

 element. 



Olsen (441 ) found that the absorption of manganese was related to 

 the degree of acidity of the soil, and that increased quantities of 

 manganese were assimilated by plants when the manganese content 

 of the nutrient solution was increased. This observation is in harmony 

 with those of Svanberg (544, 54$, 546) and of Leeper (340). 



Haselhoff (249) found traces of strontium in barley and bean plants 

 grown in pots with soils to which had been added strontium carbonate. 

 Calcium was found by Hurd-Karrer (284) to inhibit injury to plants 

 by strontium. 



Geilmann and Brunger (205) found germanium in plants grown in 

 soils in pots to which germanium had been added. 



Nemec and Kas (434) in 1923 obtained very slight increases in the 

 titanium content of plants as a result of using Na 2 Ti0 3 in pot tests. 



The influence of lead compoimds on the growth of barley was inves- 

 tigated by Keaton (311) by adding lead nitrate or carbonate to soils 

 in pots. His experiments show that while nearly all of the lead was 

 fixed in an insoluble state in the soil within a few days, some lead was 

 absorbed by the plant (2.53 to 5.40 p. p. m.) and a very large amount 

 was absorbed by the roots (94.2 to 1475.0 p. p. m.). 



Lepape and Trannoy (345) claimed to have found an increase in the 

 radium content of plants grown in soils to which radium ores had been 

 added. 



Hart, Phillips and Bohstedt .(244) studied the relation of soil 

 fertilization with superphosphate and rock phosphate to the fluorine 

 content of plants. They concluded that 



Plant materials from plots receiving fluorine-carrying phosphates, such as rock 

 phosphate and acid phosphates, for periods of sixteen to thrity-six years, did not 

 show consistent or greatly increased fluorine content over plant materials grown 

 in plots receiving a low fluorine-carrying phosphate such as bone meal. 



A rather interesting survey was conducted in 1932 by Hartwell 

 (247). He submitted three questions to several thousand agricul- 



