482 ReEpPoRT OF THE HORTICULTURAL DEPARTMENT OF THB 
The data given on page 441 show that the orchard soils of New 
York are shallow. In 3883 orchards out of 528 in this State 
the top-soil is not over twelve inches deep. The average depth 
of the top-soil in the Auchter orchard is, as we have seen, from 
nine to twelve inches. Since the rooting habits of trees are 
very different, sod may be more harmful to some varieties than 
to others. 
There is more humus in the tilled plat than in the sodded 
plat.— Humus has numerous and important functions in the 
soil for vegetable growth. The advocates of sod for orchards 
urge as one of their strongest arguments that tillage “ burns ” 
out the humus. It is granted at once that tillage without 
cover crops, green manure crops or the addition of stable 
manure or other organic matter, does decrease the humus con- 
tent. But such tillage is now seldom practiced or advocated. 
Farmer and fruit-grower know well that for any series of crops 
or on any soil organic matter must be supplied; and experi- 
ment stations and horticultural press have for years been 
urging green manure crops and cover crops as supplements to 
the dressings of stable manure which are applied at greater or 
less intervals in all commercial orchards. 
The advocates of the sod-mulch methods have offered no data 
to show that in mulched orchards in grass there is more humus 
than in tilled orchards in which cover crops or green manure 
crops have been used. This experiment furnishes some data to 
show that tillage and cover crops supply trees with even more 
humus than they get in sod with the gross cut as a mulch. 
TABLE XII.— HUMUS PER ACRE IN SOD AND TILLED PLATS AT DEPTH OF 
Srx INCHES. 

Per ct. Per ct. 
ULLV Es int eree meester ee AiO Ra seery 5S cuny - 2 Oe DPOCtantetr es tes shh. he he 
AUS UBL AIO De me ceed COUR RY a ee oo eo Debs SOC) fos Saeed 225 
ANOTABC ue ls ho eee cs Bre eee Da Oe Pere fo = se Dae 
Gain for tillage, .20 per ct. 
Gain in tons per acre, 1.8. 
