The Root and the Soil. 75 



of decomposed manure beneath the surface of the soil 

 are usually penetrated through and through with finely- 

 branched roots; and fragments of bone in the soil are 

 often inclosed in a mat of delicate rootlets. These ma- 

 terials furnish plant food in abundance. Roots that 

 penetrate the deeper and more compact layers of soil, 

 on the other hand, and those in poor and dry soils, are 

 usually little branched. It is clear, therefore, that un- 

 less a soil is well aerated (93) by a proper system of 

 tillage, and by draining if need be, and unless it con- 



FIG. 32. Showing effects of transplanting on root growth of 

 celery plants. The left two plants were transplanted when quite 

 small; the right two were not. (After Green.) 



tains abundant soluble plant food in the aerated part, 

 the roots of plants growing upon it will not branch 

 freely and hence the plants cannot be well nourished.^ 

 104. Transplanting (400) and Root Pruning (416) 

 Stimulate Root Branching. Removing the growing 

 points of either the stem or raot (65) stimulates the 



