6o 



SOIL CONDITIONS AND PLANT GRO WTH 



TABLE XV. EFFECT OF NITROGENOUS FOOD SUPPLY ON THE GROWTH OF 

 BARLEY IN SAND CULTURES. HELLRIEGEL. 



The figures are plotted in Fig 10. Similar results are ob- 

 tained on the field plots at Rothamsted (Table XVL). 



O 112 224 336 ' 44-8 



M.gms. N supplied as Ca (NOj)g 



FIG. 10. Effect of nitrogenous food supply on the growth of barley. 

 (Hellriegel.) 



TABLE XVI. BROADBALK WHEATFIELD, AVERAGE YIELDS, FIFTY-SIX YEARS, 



1852-1907. 



The increasing effects produced up to a certain point by 

 successive increments of nitrogen may be due to the circum- 

 stance that the additional nitrate not only increases the con- 



