New York Agricultural Experiment Station. 557 



peratures in the tilled land at noon. These results agree with those 

 of other experiments and with the conclusions of some of the best 

 authorities on soils. 1 



We have no definite knowledge as to whether the apple prefers 

 a warm or a cool soil but in the comparatively cold soils in which 

 the apple is grown in New York, general considerations lead us 

 to believe that the warmer soil is the better. To give reasons: 

 Heat would cause food substances to dissolve more rapidly; hasten 

 diffusion; aid in soil ventilation; develop stronger osmotic pressure 

 in roots; and help in the formation of nitrates. The augmentation 

 of these several processes would, it is almost certain, accelerate 

 vegetative activity sufficiently to make the higher temperature of 

 the tilled land one of the factors accounting for the more nourishing 

 condition of the trees under tillage. 



Sod injures apples by diminishing the supply of air in the soil. — 

 We have no data to prove the contention set forth in the heading 

 of this paragraph but concrete evidence is not necessary. All must 

 agree that air is of vital importance to every part of a plant — to 

 the roots scarcely less than to the tops of trees. Beneficient bacteria 

 depend, if anything, to even a greater extent upon an ever present 

 supply of oxygen. The formation of nitrates requires the addition 

 of oxygen to some one or another of the compounds of nitrogen. 

 Oxidation plays an important part in all of the chemical changes 

 which take place in the soil and is therefore necessary in keeping 

 up fertility. 



All will grant the proposition that there is more air in a cultivated 

 than in a sodded soil. Nothing can be more apparent than that, 

 when soil particles are held in a close, compact mass as in unculti- 

 vated land, there is comparatively little room for air and that when 

 the particles are separated by stirring the soil fresh air must be 

 drawn in. When the air is renewed by stirring the soil several 

 times during a season there cannot but be a most beneficient effect 

 on the plats growing therein. These considerations need no data 

 to prove them, they are corner-stones in agriculture, and justify 

 us in settling upon a diminished air supply as one of the causes for 

 action against grass in an orchard. 



1 Woburn 3rd Report: 45. 1903. 



Soils. By E. W. Hilgard. New York: 1906, p. 305; The Soil. By F. H. King. 

 New York: 1895, pp. 221-225. 



