142 LENGTH OF ROOTS. 



importance of deep pulverization may be stated as 

 follows : 



1. The range of the roots is increased. It is 

 scarcely possible to limit the extent to which the 

 minute roots of trees may spread themselves in 

 search of food in well-prepared ground. It has 

 been said by some writers that the distance from 

 the trunk to the termination of the roots was the 

 same as the height of the tree ; but careful investi- 

 gators have discovered that fibers, invisible to the 

 eye, extend far beyond this. An experiment of 

 Tull's is presented which aptly illustrates this point. 



CO 



d , 



" Two pieces of land, or ridges, were drilled with 

 turnips, in rows a foot apart, and were very even in 

 them ; the ground at both ends and on one side 

 was hard and unploughed, and the turnips, not 

 being hoed, were very poor, small, and yellow, except 

 the outside three rows {be and d) which stood 

 next to the ridge (<?), which land, having been 

 ploughed and harrowed at the time a should have 

 been, gave a dark flourishing color to these three 



