Planting 141 



cultivation in the fall or early spring than by tillage during 

 the life of the potato. The reserve of nourishment in the 

 root stalks enables them to stand punishment for several 

 weeks and recover from it to injure the potato after 

 tillage is no longer possible. 



The preceding results of tillage have all been favorable 

 to the potato plant. Tillage has another action which 

 has not been sufficiently studied and which has led to 

 many conflicting results in experiments and in farmers' 

 practice. It is a fact that tillage can injure the potato 

 plant even easier than it can the tough and hardy weeds. 

 It is very difficult to work with soil near the potatoes 

 without injuring them. As the season advances, this 

 becomes more dangerous to the potato. While the 

 young plant is still attached to the seed piece and draw- 

 ing on it for nourishment, it can lose part of its small 

 roots without great loss, particularly as the weather is 

 yet cool and favorable to the vitality of the crop. Each 

 day the potato grows older increases the danger of loss of 

 yield from injurious root injury. In the later part of 

 the plant's life, the whole upper soil becomes filled with 

 roots. These come so close to the surface that it is most 

 difficult to work any tillage tool without some injury. 

 Few tools except the hand hoe can be worked as shallow 

 as one inch, and many of the larger roots are that close 

 to the surface. Under some conditions, late tillage may 

 do less injury to the potatoes than under others. In 

 periods of abundant rainfall, the plants may tend to 

 root too close to the surface and some root-pruning may 

 force the potato to root deeper. If drought comes later, 

 this will be a benefit to the crop. In very cool seasons 

 in which the potato does not suffer from extreme heat, 

 root-pruning by tillage tools does less damage than in 



