Fertilizers and Shade-crops 193 



Many young trees are lost each year in the colder 

 districts as a result of "freezing dry." This term is used 

 to denote a condition that may be induced in different 

 ways. The usual cause is merely a lack of water in the 

 soil in the winter. Trees give off water in cold weather 

 from twigs and limbs, and if the supply is not replenished, 

 death results. A similar effect is produced when a damp 

 soil is frozen to such a depth that root action is suspended. 

 The tops of such trees usually die after a feeble attempt 

 at putting forth leaves, while the roots are usually in 

 perfect condition. 



The lack of water may be avoided by winter or late 

 fall irrigation. The deep freezing presents more of a 

 problem, but we think that it may be prevented to a 

 considerable extent by the use of shade-crops. True, 

 the system we propose contemplates plowing in the fall, 

 but eastern experience proves that as much protection 

 from frost is. secured when a crop is plowed into the land 

 in the fall as when it is left standing throughout the winter. 



The winter of 1903 to 1904 was very severe in the East, 

 and in some sections hundreds of orchard trees, partic- 

 ularly peach trees, were destroyed. Green 1 made a 

 survey of the injured orchards the following summer, 

 and found that injury occurred only on improverished 

 and bare soils. A cover-crop, sod, good growth of weeds, 

 or stable manure afforded almost complete protection 

 from the cold. And, moreover, and what is more impor- 

 tant for our purpose, he found that when such materials 

 had been recently plowed under, the protection was just 

 as effective. 



1 Green, W. J,, Qhjo Agri. Exp. Sta. BuJ. 157, 1904. 

 Q 



