Agriculture Reference
In-Depth Information
ile in the soil, can leach out of the root zone in poorly managed orchards.
Remember: When applying potassium fertilizers, base your rates on the K
2
Other nutrients.
While other macronutrients can be deficient in orchard
soils, careful preplant soil testing and site preparation should prevent sig-
nificant problems from developing. Boron, iron, and zinc are micronutrients
that are occasionally deficient in orchards. In many cases, the nutrients are
actually available in adequate amounts in the soil, but their availability to
plants is limited by pH values that are too high or low, excessive amounts
of other nutrients, and soils that are wet and cold. Depending on soil condi-
tions, boron can leach from the root zone. These elements are easily added to
the orchard by applying compost, boric acid, chelated foliar sprays, and oth-
er materials. Tissue testing, as discussed below, is the most effective method
for tracking macro- and micronutrient status in orchard crops.
It bears repeating: In planning and carrying out your site preparation and
soil nutrition program, avoid the temptation to add excessive amounts of nu-
trients to the soil. Adding too much calcium or phosphorus, for example, can
trigger the onset of iron chlorosis and apparent deficiencies of copper and
zinc, even though these nutrients are plentiful in the soil. Excessive potassi-
um can trigger or exacerbate apparent calcium and magnesium deficiencies
by interfering with plant uptake of these nutrients. Strive to develop and
maintain balanced soil and plant nutrition profiles.
Determining the Nutrient Status of Your Crop
You need to know the nutrient status of your crop to make effective de-
cisions about fertilization and orchard floor management. You can find re-
commendations to apply 60 to 90 pounds of nitrogen per acre per year, but
such recommendations do not take into account your orchard's soil types,
precipitation and irrigation, climate, training systems, fruit varieties, and
management practices. In short, they are not particularly useful, especially
