Agriculture Reference
In-Depth Information
green veins. Unless corrected, affected trees become weakened and stunted
with poor fruit production. Under severe conditions, trees may eventually die.
Similar micronutrient deficiency disorders are sometimes seen with a lack of
available boron, manganese, and zinc, even when the nutrients are relatively
ability to plants.
Most tree fruits tolerate pH values between 5.5 and 7.5. For a productive,
healthy, long-lived orchard, a pH of 6.0 to 7.0 should produce excellent res-
ults. Bear in mind that the soil pH fluctuates during the year due to wetting
and drying, microbial activity, and chemicals added to and removed from the
soil by plants. In western Oregon orchards, for example, the soil pH typically
fluctuates up to 0.5 pH unit and can fluctuate twice that amount on sandy
soils. There, the highest soil pH is usually recorded in late winter. Soil drying,
increased microbial and plant activity, and fertilizer applications cause the
pH to drop during the growing season, reaching an annual low in late sum-
mer or early fall.
