Good Fruit Grower

April 15

Issue link:

Contents of this Issue


Page 20 of 47

Nutrient needs of apple trees Essential nutrients need to be in balance, neither too low nor too high. by Geraldine Warner pple trees need annual supplies of mineral nutrients, either from the environment or in the form of applications by the grower, in order to develop rapidly and produce high yields. Essential elements include the macronutrients carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, and magnesium, and the micronutrients sulfur, iron, boron, manganese, copper, zinc, molybdenum, chlorine, and nickel. For optimal growth and fruiting, essential nutrients must be kept in balance. Levels that are too low will negatively impact the tree and fruit quality, while levels that are too high can be toxic to the trees. Nitrogen (N): Nitrogen must be considered according to the variety, tree age, crop load, and tree vigor. Levels should be lower as the trees mature. The aim should be to have relatively high levels early in the season to encourage rapid leaf development, fruit set, and flower bud formation, and lower levels later in the season to favor color development of the fruit and winter hardening of the tree. Phosphorus (P): Phosphorus levels in leaf samples vary by variety. Availability of phosphorus is strongly influenced by soil pH. Low values may be linked to low soil pH levels. High phosphorus values frequently result from an accumulation of phosphorus when growth and leaf expansion are limited by deficiencies of other elements, such as zinc. Potassium (K): Potassium-deficient trees may produce small, dull-colored fruit with poor flavor, and be susceptible to winter cold injury. Moisture stress may limit the availability of potassium and result in low levels in leaves. Calcium (Ca): Low levels in leaves may reflect low pH levels or inadequate lime applications. Low leaf calcium can also result from boron or zinc deficiency. High calcium levels in leaves are usually correlated with high leaf nitrogen levels because both nitrogen and calcium are moved to the leaves in water due to transpiration. Where there is strong shoot growth in the top of the tree, calcium chloride sprays are recommended. The number of applications appears to be more important than the amount of material per application. Magnesium (Mg): Insufficient magnesium can cause premature fruit ripening and fruit drop. Blind wood, a lack of bud development, and weak brittle spurs are also common symptoms of magnesium deficiency. Magnesium can be boosted with applications of Epsom salts (magnesium sulfate). Boron (B): Boron is essential for development of new tissues in shoot tips, flowers, fruit, and roots. Shortages are common on coarse-textured soils. Boron is very soluble and mobile in the soil and easily leached. Low boron levels are often associated with calcium deficiency. Common symptoms include corking and cracking of the fruit. Zinc (Z): Zinc regulates growth and fruiting and plays a role in pollen tube growth. It also influences calcium metabolism as well as the cold hardiness of trees and frost hardiness of flowers. High phosphorus levels can inhibit zinc uptake. Symptoms of zinc deficiency include poor leaf and shoot growth, reduced flowering and fruit set, and smaller, poorly colored fruit. Manganese (Mn): Deficiencies are found more frequently on high-pH soils and coarse-textured soils. Manganese is involved in photosynthesis. Deficiencies are not usually apparent until the leaves show chlorosis. Iron (Fe): Iron content of leaf samples can cover a wide range, depending on soil, weather, and contamination of samples by dust. Chlorosis on rapidly growing shoots is a symptom of iron deficiency, but deficiencies are uncommon in most orchards. Copper (Cu): Shortages can be a problem on coarse soils and soils with a high pH level. It is not mobile in soil. Copper is involved in processes relating to photosynthesis. Symptoms of deficiency include stunted leaf and shoot growth, reduced flowering and fruit set, and small, poor quality fruit. • Source: New York Fruit Quarterly, Spring 2004, written by horticulturists at Cornell University and published by the New York State Horticultural Society, SUPER! FANTASTIC! WONDERFUL! AWESOME! VALUABLE! …those are just a few of the words we use to describe our customers. We love what we do, and you make it possible! A special THANK YOU to all of our loyal customers who come back to us year after year. ProTree Nurseries is dedicated to providing the best selection of apple and cherry trees, grafted on the heartiest rootstocks. If you're looking for a variety you can't find anywhere else, call ProTree Nurseries today. APPLES Banning Red Fuji (USPP 16,624 P2) Rising Sun Fuji® RubyJon® Granny Smith Hilwell Braeburn Beni Shogun (USPP 7526) (USPP 10,115) (USPP 7997) Honeycrisp™ RubyMac® Blondee™ (USPP 7197) (USPP applied for) (USPP 19,007 McLaughlin cv) Indian Summer Crab Joburn™ Braeburn Schlect Spur Delicious™ September Wonder™ Fuji (USPP 11,193) Simpson Crab Snowdrift Crab Torres Fuji™ Brookfield® Gala (USPP 10,016) Buckeye® Gala (USPP 11,992) JonaStar JonaGold™ (USPP 20,590) LindaMac® (USPP 10,840) ® (USPP 12,900) (USPP applied for) Manchurian Crab Midnight Red Spur™ Ultima™ Gala (serial 74/458,730) Zestar!™ (USPP 16,620) Pacific Gala® (USPP 11,367) Frettingham Crab Golden Delicious (USPP 9681) (USPP 21,300) Crimson Gold Crab Dandee Red® (USPP 13,753 P2) Pearleaf Crab These apple varieties are available on B-10, B-118, EMLA-7, EMLA-26, EMLA-106, EMLA-111, G-11, G-16, G-30, M-9 337T, NIC®-29, or Supporter 4. CHERRIES ™ ™ ™ ™ ® ™ ® ™ ™ ™ ® ® Available on Colt, Gisela®, Krymsk®, Mahaleb, or Mazzard.* *Not all varieties are available on all rootstocks. Call for specific grafting information. 741 Sunset Road, Brentwood, CA 94513 800.634.1671 (Alison Clegg or Richard Chavez) 877.457.6901 (Henry Sanguinetti) Fax 925.634.6040 GOOD FRUIT GROWER April 15, 2013 21

Articles in this issue

Links on this page

Archives of this issue

view archives of Good Fruit Grower - April 15