CERTAIN ELEMENTS IN NURSERY PRACTICE 177 



The best nursery lands contain a basis of clay, and these are 

 the kinds that soonest suffer under unwise treatment. The 

 land is kept under high culture, and it is therefore deeply pul- 

 verized. There is practically no herbage to protect it in 

 winter. When the crop is removed, even the roots are taken 

 out of the soil. The tree-lifter or digger is likely to be used 

 when the land is wet and easily injured. For four or five 

 years, the land receives practically no herbage that can rot and 

 pass into humus. The trees are dug in the fall, often when 

 the soil is in unfit condition, and this fall digging amounts to 

 a fall plowing. The soil, deeply broken and robbed of its humus, 

 runs together and cements itself before the following summer ; 

 and it then requires three or four years of "rest" in clover or 

 other herbage crop to bring it back to its rightful condition. 

 This resting period allows nature to replace the fiber in the soil, 

 and to make it once more so open and warm and kindly that 

 plants can find a congenial root-hold. 



It would seem, therefore, that some of this mechanical injury 

 to nursery lands should be prevented by the growing of cover- 

 crops between the rows late in the season, to be plowed under 

 the following spring. It is well known that the plowing-in 

 of coarse manure between the trees in fall or spring, for two or 

 three years, will sometimes so greatly improve the land that a 

 second good crop of trees can be grown with ease. This is 

 particularly true for plum trees, as already noted, but the 

 results do not seem to be so well marked for pears and some 

 other trees. It is probable that one reason for the very general 

 refusal of pear trees to follow pear trees is the fact that they 

 are likely to be grown on heavy clay, and this is just the land 

 most injured by nursery practices. Some lands are naturally 

 so loose and open in structure that two or three crops of trees 

 can be grown in succession but these lands contain little crude 

 clay, and therefore do not suffer quickly from the passing out 

 of the humus. 



