192 



SOILS AND MANUEES 

 REQUIREMENTS OF THE CROPS. 



Chemical Composition. The chemical composition of 

 the crops does not afford a very clear indication of their 

 manurial requirements, because some of them can obtain 



FIG. 28. 



a larger proportion of the fertilising ingredients directly 

 from the soil and are less dependent upon manures 

 than others. Any deductions drawn from the chemical 

 composition of the crops cannot, therefore, be regarded 

 as conclusive unless all the other circumstances con- 

 nected with their growth have also been taken into 



