STATK POMOLOGICAIv SOCIETY. 85 



where the weather during the fall is normally dry, the injury 

 is less than in summer, since plants evaporate less from 

 their leaves in the cooler weather and shorter days of fall than 

 in the longer and hotter days of summer. Cover crops not only 

 do not, as a rule, dry out the soil injuriously, but they also add 

 directly to the moisture-holding capacity of the soil by the humus 

 formed in their decay, and they hold much of the snow until 

 it melts and is absorbed by the soil. 



Another reason why cover crops are rarely as injurious as 

 ■crops grown throughout the entire season, and are often bene- 

 ficial, is that their growth is made after the trees have stopped 

 growing and are maturing their wood for winter. The Michi- 

 gan Station has shown that the majority of trees in that locality 

 complete their growth by July. Of course the conditions ob- 

 served in Michigan do not occur in all climates or seasons, but 

 they show unmistakably the tendency of trees to make their 

 greatest growth early in the season. Trees, therefore, require 

 much less moisture in the latter part of the season than they do 

 in the early part. Indeed, in moist localities it is often thought 

 to be a distinct advantage to stop cultivation by midsummer 

 and grow some secondary crop which will check the growth 

 of the trees and cause them to mature before winter. The 

 Washington Station, in studying the unusuallv severe freeze 

 occurring in the fall of 1896, found that in most instances late 

 summer cultivation had an injurious effect similar to late irri- 

 gation. "Wherever cultivation or irrigation had been kept up 

 late in the season and the ground was moist and the trees in an 

 active growing condition, there the frost did most damage." 



Among other benefits to be derived from cover crops is the 

 checking of washing and leaching of the soil. Light soils are 

 often gullied by heavy rains in the fall, just as in summer, and 

 some crop to bind such soils is beneficial. In the case of soil 

 leaching and the consequent loss of plant food, especially 

 nitrates, a crop is more valuable in the fall and early winter than 

 ■earlier in the season, for in spring and summer the tree roots are 

 in condition to take up much of the plant food as it becomes 

 available; but from the time their leaves fall until the soil is 

 frozen, the plant food which would otherwise escape in the 

 drainage water, or be washed down beyond the reach of plants, 

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