MINERAL COMPOSITION" OF CROPS 



25 



Table 8. — Calcium and potassium in pine needles and in the soils in which the 



trees grew 



[Fliche and Grandeau (186)] 



Locality and material 



Constituent as per- 

 centage of ash 



Locality and material 



Constituent as per- 

 centage of ash 





CaO 



K 2 



CaO 



K 2 



Quatre-Arpents: 

 Soil 



Percent 



0.35 



.20 



40.20 



Percent 



0.07 



.03 



16.04 



Bas-du-Cellier: 

 Soil- 



Percent 



3.25 



24.04 



56.14 



Percent 

 0.04 





Subsoil 



Pine needles. 



.16 





11.09 









Liebscher and coworkers (352) in 1898 determined the potassium, 

 nitrogen, and phosphorus contents of oat plants grown in pots con- 

 taining 24 different German soils. The tests were conducted under 

 fairly uniform conditions, and the results may reasonably be expected 

 to show differences in the soils. The phosphorus content of the 

 plants, for example, varied from 0.141 to 0.419 percent, and the 

 potassium from 0.648 to 2.610 percent. The high value for potassium 

 in the plant agrees with a high content in the soil in which it was 

 grown, but with the lower values there is no agreement. Likewise, 

 there is no correlation between the phosphorus content of the plants 

 and of the soil. 



One of the first attempts at a systematic study of the soils of the 

 United States was initiated in 1895 by Wiley, Moore, and Ewell, of 

 the Division of Chemistry of the United States Department of Agri- 

 culture (23x). Forty-four soils, some virgin and some cultivated, 

 were collected from widely separated localities and brought to Wash- 

 ington to be used in greenhouse-pot tests. Oats and buckwheat in 

 one series of tests and beans and buckwheat in another were the 

 rotations used each year over a period of about 8 years. The crops 

 were grown under uniform conditions, except for the soils used, and 

 the results (unpublished) show wide variations in the nitrogen, 

 potassium, and phosphorus contents of these crops. Thus the 

 potassium content of the oat plant varied from 1.23 to 3.34 percent 

 of the dry weight, depending on the soil in which it was grown, while 

 the phosphorus varied from 0.15 to 0.52 percent in the same series. 

 For example, the data show that all crops grown in a virgin sandy 

 loam from Massachusetts had very low contents of both potassium 

 and phosphorus, while those grown in an adobe soil from California 

 were high in both of these elements. Of course these pot tests do 

 not reflect local conditions such as the natural moisture content of 

 the soil, climatic factors, and other environmental characteristics 

 found in the field; but they do indicate some fundamental differences 

 in soils and their ability to supply, under ideal conditions, those 

 elements essential to the health and well-being of the animal con- 

 suming the products of that soil. 



Other work of Moore's includes pot and field tests made in 1903 of 

 soils in the northern part of the United States (415) and an unpub- 

 lished report of a field investigation of about 5 different soil types in 

 26 localities in Kentucky (16x). The data from the latter report 

 show differences up to 150 percent in the phosphorus and potassium 

 contents of the hemp plant, and even greater differences in magnesium 



