438 Reporr or tHe HORTICULTURAL DEPARTMENT OF THE 
two plats of this experiment are mainly due to differences in 
moisture, the tilled plat having most moisture. 
As a consequence of the reduced water supply in the sod plat, 
there is a reduced food supply; for it is only through the medium 
of free water that plants can take in food. Analyses show that 
the differences between the actual amounts of plant food in the 
two plats are very small. | 
Analyses show that there is more humus in the tilled plat 
than in the sod plat, contradicting the oft made assertion that 
the tillage method of managing an orchard “‘burns out the humus.”’ 
At a depth of six inches, the tilled soil is 1.1 degrees warmer 
in the morning and 1.7 degrees at night, than the sod land; at 
twelve inches the tilled soil is 2.3 degrees warmer in the morning 
and 1.8 degrees in the evening. 
We are justified; without the presentation of specific data, 
in saying that a tilled soil is better aerated than sodded land. 
Soil investigators are well agreed that beneficial micro-organ- 
isms are found in greater numbers in a cultivated soil than in 
other soils. 
The following application of the results of this experiment 
may be made: 
Nearly all the plants which minister to the needs of man are 
improved by tillage; the apple does not seem to be an exception. 
Results as positive as in this experiment can be made very. 
comprehensive; they should apply to all varieties of apples and 
to nearly all soils and locations. 
The experiment does not show that apples cannot be grown in 
sod; it suggests, however, that apples thrive in sod, not because 
of the sod, but in spite of it. 
While moisture is by no means the only factor to be considered 
in the controversy over the sod and tillage methods of manage- 
ments, it appears to be the chief one. 
There is nothing in this experiment to indicate that trees will 
become adapted to grass. The sodded trees began to show ill- 
effects the first year the orchard was laid down to grass and each 
succeeding year has seen greater injury. 
