CHEMICAL ANALYSIS OF SOILS 



325 



Table LXXIII 



THE PERCENTAGES OF NITROGEN AND CALCIUM IN THE DUNKIRK 



SILTY CLAY LOAM AND THE VOLUSIA SILT LOAM AND THE 



NITROGEN REMOVED BY CERTAIN CROPS. CORNELL 



LYSI METER TANKS. 



and in a general way there is often some correlation between 

 the amount of calcium present and the productivity. In 

 humid regions soils high in lime are usually fertile. Within 

 certain limits, therefore, calcium becomes significant in fer- 

 tility studies. 1 



Some idea concerning the relative value of the various chem- 

 ical methods, especially those dealing with potash, lime, phos- 

 phoric acid, and magnesia, may perhaps be obtained by com- 

 paring actual data. Burd 2 has analyzed a number of soils, 



^hedd, O. M., A Proposed Method for the Estimation of Total 

 Calcium in Soils and the Significance of this Element in Soil Fertility; 

 Soil Sci., Vol. X, No. 1, pp. 1-14, 1920. 



a Burd, J. S., Chemical Criteria, Crop Production and Physical Classi- 

 fication in Two Soil Classes; Soil Sci., Vol. V, No. 6, pp. 405-419, 1918. 



