Commencing in Solano County, about eight miles northwest of Suisun and
extending as far north as the southern end of Shasta County, close to
the base of the foothills on the west side of the Sacramento River, are
a large number of orchards on the bottom lands of the valley. These are
found principally on the higher lands along the banks of streams flowing
from the Coast Range in a generally easterly direction to the Sacramento
River. The two most important streams of this type are Putah Creek,
forming the boundary between Yolo and Solano counties, and Cache Creek,
flowing through the Capay Valley and across Yolo County to the Sacramento
River.
These plantings being on the floor of the valley are more subject to
frost than the foothill plantings, but they have the advantage of being
on the rich valley soils, and while they may lose a crop occasionally
from frosts, they make it up in the long run by the much larger growth of
the trees and their ability to produce larger yields. Many orchards do
not show any such ability to produce large crops, but such a failure must
be attributed to lack of pruning and care, rather than to any inherent
inability of the large trees to produce nuts. Again, trees on the rich
and moist bottom lands may be kept so vigorous and healthy by good care
that they are apparently able to endure lower temperatures than less
vigorous trees on the shallow and poor upland soils where frosts are less
common or severe.
Many recent plantings have been made along the lower foothills on the
west side of the Sacramento Valley. The three most important districts
where these plantings have been made are west of Dunnigan, Arbuckle
and Corning. The plantings in these districts are mostly on a gravelly
clay or clay loam soil which is not as rich nor generally as deep as
the bottom lands and, consequently, the trees are somewhat smaller, but
they have the advantage of freedom from spring frosts due to superior
air drainage. The problem in this district is chiefly one of moisture
retention by cultivation, as in most cases the growers are unable to get
water for irrigation at a reasonable cost, if at all.
The valley districts extend to Tehama County and down the east side of
the Sacramento River, the same as on the west side, the principal centers
being at Chico, Durham, Liveoak, Pennington and Sutter. Parts of the
Liveoak section are too low and many orchards have suffered from poor
drainage both of water and air.
The foothill sections on the east side are principally around Antelope,
Fairoaks and Orangevale in Sacramento County and the southern end of
Placer County. Here the danger from frost is slightly greater than on the
western foothills because of the proximity to the snow-covered Sierra
Nevada Mountains. On the other hand, water from the Sierras renders
irrigation possible at a reasonable cost, so the trees can be kept in
good condition. Care must be exercised here to avoid frost pockets. There
is also danger of poor soil drainage in the swales.