86 ORCHARD CULTURE 



handled it is usually a more expeditious method. I£ the disc 

 harrow is run through the orchard in one direction and then the 

 land is allowed to stand a few days, to be followed by a discing 

 in the other direction, twice over the land will usually put it 

 in good condition for the spring-tooth or some other harrow. 



Early Tillage Affects Moisture. — The desirability of fitting 

 the land as early in the spring as possible is very frequently 

 overlooked by the orchard man, who has on the land a crop of 

 clover or some other crop which lives through the winter. He 

 thinks that he ought to let it grow for a time in order to get 

 additional humus to plow under, and the temptation to get all 

 he can in the humus line frequently gets him into serious diffi- 

 culties. Of course it is expected that when the land is plowed 

 in the spring a certain number of roots will be destroyed by 

 the plows, but if the land is plowed each year the roots so cut 

 will never have attained any great size and they will be replaced 

 at once by new feeding roots which will come up into the soil 

 which was turned over. Moreover when this is done in the early 

 spring the tree will not feel the temporary loss of moisture, be- 

 cause at this time of year the loss of moisture by transpiration 

 from the tree is relatively very small. 



It ought also to be emphasized, in this connection, that the 

 little root hairs which do most of the actual absorbing of soil 

 moisture do not persist over winter but a new set is developed 

 each spring. Now suppose that the orchard man, in his zeal to 

 get extra humus, allows his cover crop to grow until June 

 before plowing. In the first place this will seriously exhaust the 

 soil moisture by the extra drafts made upon it to grow the cover 

 crop; then an inunense number of feeding roots and root hairs 

 will have been developed in this surface layer of the soil which 

 is turned over by plow. The loss of these roots, or rather of the 

 soil moisture which they are taking in, while it would not have 

 been felt by the tree in the least had it occurred in the early 

 spring, is now very seriously felt, since the tree is in full leaf 

 and giving off to the air an immense amount of moisture daily. 

 If we add to this the further fact that this heavy layer of cover 

 crop, both the autumn growth and the spring growth, interferes 



