MINERAL COMPOSITION OF CROPS 



35 



According to the author, 



The wide variations in climate in different parts of Illinois have made it very 

 difficult to study the effect of soil types, throughout the area of their occurrence, on 

 the composition of corn stover. Widely different soil types ordinarily do not occur 

 on the same experimental field; therefore, seldom under the same seasonal con- 

 ditions of rainfall, temperature, and other climatic factors. Because of these and 

 other limitations (particularly variety of plant), comparisons that will show the 

 effect of soil type on the composition of stover are indeed rare. 



Grizzard {229) determined the variations in composition of the 

 leaves and the stems of alfalfa plants grown in different soils in dif- 

 ferent localities of Michigan. Differences of 105 percent of phos- 

 phorus and 73 percent of calcium in the leaves of the plants were found. 

 The author states: 



The heavy soil types, such as Brookston clay loam, tend to give a higher nitrogen 

 content in the alfalfa plants than the lighter soil types, such as Isabella sandy 

 loam, both when fertilized and unfertilized. On the other hand, the lighter soil 

 types tend to give a decidedly higher phosphorus content in the alfalfa plants than 

 the heavy soil types, this being true both in the fertilized and the unfertilized 

 condition. In the case of calcium, there is a tendency for this element to be 

 decidedly higher in the intermediate soil types, such as the Gilford and Brookston 

 loams, than in either the heavy or light soil types. Apparently, these data indi- 

 cate that soil type predominates over fertilizer treatments in the composition of 

 alfalfa; although fertilization tends to influence the composition of alfalfa, especi- 

 ally in certain soils. 



Some of the factors responsible for the variation in the calcium and 

 phosphorus contents of peas were studied by Peterson and coworkers 

 (4'x). A summary of their unpublished data is given in table 16. The 

 date indicate that peas grown in the Knox soil contain less calcium 

 than those grown in the other two, and that variety of peas may 

 influence the absorption of calcium. 



Table 16. — Calcium and phosphorus contents of Wisconsin peas 1 

 [Peterson and others (4x)] 



Variety of pea and soil type 



Ca 



P 



Variety of pea and soil type 



Ca 



P 



Smooth Alaska: 



Miami silt loam . . 



Percent 



0.263 



.203 



.179 



Percent 



0.649 



.578 



.582 



Perfection: 



Miami silt loam . 



Percent 



0.226 



.174 



Percent 

 0.611 



Carrington silt loam 



Knox silt loam.. 



Carrington silt loam 



.640 







i Moisture-free basis. 



Holtz (275) in 1930 studied the variations in calcium and phosphorus 

 contents of oats and red and white clover grown in different western 

 Washington soils in different localities. He concludes that "the cal- 

 cium content of oat hay is influenced by the calcium content of the 

 soil in any particular group," that is, residual, glacial or alluvial soils. 

 The composition of oat hay and red clover both follow the available 

 phosphorus in the residual soil, but in the upper glacial soils the com- 

 position of oat hay responds to the total phosphorus content of the 

 soil, whereas clover follows the available phosphorus. The results of 

 the experiments were influenced, of course, by climate and other 

 factors as well as by the soil itself. Other investigations of Washing- 

 ton soils include those of Baker and Vandecaveye (44) m 1935 and 

 Vandecaveye and Bond (572) reported in 1936. 



