36 MISC. PUBLICATION 3 6 9, U. S. DEPT. OF AGRICTJI/EUBE 



Greaves and Anderson {220) reported in 1936 that the copper con- 

 tent of wheat, barley, and oats (grains) varied tremendously as grown 

 in different localities. No correlation was found, however, between 

 the content of copper in the wheat and that of the soil. These 

 investigators also determined the copper content of several varieties of 

 wheat grown in the same soil and concluded "that variety is more im- 

 portant than soil, except where the copper content of the soil faUs 

 below a certain minimum." The variations that they found on 

 different soils are in direct contradiction to some unpublished work 

 of Bailey and Hutchinson (lx), who found practically no variation in 

 the copper content of wheats grown over a large part of the northwest- 

 ern wheat country. 



The sulfur contents of two samples of alfalfa grown in two localities 

 in Utah were not significantly different, according to Evans and 

 Greaves (169). No descriptions of the soils were given, but the sulfur 

 contents of the soils were quite different. 



A recent comprehensive survey of New Mexico grasses by Watkins 

 (579) indicated that there were 12 counties in New Mexico in which 

 the average phosphorus content of the range grasses for the year 1932 

 was insufficient for normal growth and reproduction of range cattle. 

 However, the grasses were collected late in the fall and early in the 

 spring, so that the samples might have been leached, and undoubtedly 

 they did not represent whole plants of any particular stage of maturity. 



The effect of soil type on the composition of clover was studied by 

 Myers and Metzger (425) in Kansas, but no indication is given that 

 the samples chosen were consistent in stage of maturity. 



Poehlman (469), investigating in 1935 the analyses of plant juices 

 as indicators of the nutrient needs, found that 



the phosphorus and potassium concentration in the plant juice differs significantly 

 with the different soils [in Missouri] upon which the plants were grown and the 

 soil type is an important factor in determining the concentration of these elements 

 in the plant juice. 



He states, however, that uncontrolled factors in his experiments 

 include " variations due to age or maturity of the plant, moisture con- 

 tent of the plant, rate of growth, soil heterogeneity, and climatic factors 

 such as light, temperature, rainfall, humidity and soil moisture." 



Daniel and Harper (134), m studying the composition of prairie 

 grasses in Oklahoma in 1934, found that the moisture relationships in 

 the soil were very important with respect to the phosphorus content 

 of the plant. Thus, a sample of grass (Andropogon Jurcatus Muhl. 

 and A. scoparius Michx.) collected from an alluvial soil where moisture 

 conditions were favorable during the growing season contained more 

 than twice as much phosphorus as usually occurs in the average 

 sample of upland prairie hay. 



Variations in the nutrient content of soils have less effect on the 

 seed than on any other part of the plant. A comparative analysis of 

 Chinese and American rices by Davidson and Chambliss (139) in 

 1932 did not "indicate any striking differences in composition between 

 the Chinese rices, grown on a soil presumably cropped for thousands 

 of years, and the rices grown under the American method of cropping." 



Lincoln (354) studied differences in soil and plant relationships by 

 examining samples of Stenotaphrum dimidiatum Bronger, growing in 

 Mauritius pastures. Samples collected at the same stage of growth 

 varied considerably in composition, depending upon the character of 



