18 BULLETIN 614, UD. S. DEPARTMENT OF AGRICULTURE. 
an average yield of only 21 boxes more per acre under clean-cultural 
than under mulch-crop management in the Yakima district, while 
in the Zillah district there would be an average yield of 42.1 boxes 
more per acre under clean-cultural management. 
A few years ago all men in the valley practiced clean cultivation. 
Of late years many of the orchards have been sown to alfalfa or 
clover. (See fig. 3.) In many cases the orchards which were clean 
cultivated showed the effect of too intensive cultivation and the 
need of humus. There seems to be a tendency on the part of some 
growers, after orchards have been sown to a mulch crop, to neglect 
the orchard in different ways. These seemingly small oversights 
have their effect on the physical condition of the trees, and thus 
Fic. 3.—An 8-year old Esopus and Winesap orchard in the Zillah section. The Esopus trees are badly 
affected by blight. Note the dense mulch crop of alfalfa. 
upon the yield. This is especially noticeable in the Zillah district, 
where men are using their mulch-crop orchards for pasturing hogs. 
On the whole, these orchards are not managed so carefully and thor- 
oughly as those under clean cultivation. Great care must be taken 
with the Yakima Valley orchards in a mulch crop until the practice 
has been in vogue for a sufficient time to enable the growers to become 
familiar with the details and results of mulch-crop management. 
Not alone in the Northwest does there seem to be this tendency to 
neglect orchards in mulch crop, but in some of the larger commercial 
apple-producing sections of the Kast a similar tendency is apparent, 
especially when the price of apples does not seem to warrant scru- 
pulous care. 
