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Table 1 Tree nutrient requirements in relation to yield Fruit yield (bushels N per acre) 500 1000 1500 2000 P K Ca Mg S (pounds per acre) 22.1 3.7 40.2 44.3 7.4 80.3 66.4 11.1 120.5 88.6 14.8 160.6 15.9 4.9 1.8 31.8 9.8 3.6 47.7 14.7 5.4 63.6 19.6 7.2 SOURCE: Cheng and Raba (2009), New York Fruit Quarterly 17(4): 5-10 Table 2 Leaf analysis standards for tree fruits (dry basis) Element Nitrogen Crop Young nonbearing apples and pears Young bearing apples and pears Mature soft apples and pears Mature hard apples and processing Cherries plums, prunes Peaches Phosphorus All crops Potassium All crops Calcium All crops Magnesium Apples and pears Stone fruits Boron Apples and pears Stone fruits Zinc All crops Copper All crops Manganese All crops Iron All crops A thousand bushels of Gala apples removes 3.5 pounds of calcium (see Table 2), and this spray program adds between 7.5 and 13.2 pounds of calcium per acre. Magnesium McIntosh is very susceptible to magnesium deficiency, and Cheng recommends foliar application of 10 to 15 pounds of Epsom salt (magnesium sulfate) per 100 gallons of spray at petal fall and second cover. Low soil pH or high potassium levels can lower leaf magnesium. The ratio of potassium to magnesium should be four to one, or less. Potassium Of all the nutrients, apples need potassium the most. Requirements are related to yield in a linear fashion. A thousand bushels of Gala apples will require addition of 55.3 pounds of potassium; 500 bushels, half that; 2,000 bushels, twice that. Potash is 83 percent potassium. Removal of nitrogen, phosphorus, potassium, and boron by fruit harvest is • Desired level 2.4-2.6% 2.2-2.4% 1.8-2.2% 2.2-2.4% 2.4-3.4% 3.0-4.0% 0.13-0.33% 1.35-1.85% 1.3-2.0% 0.35-0.50% 0.40-0.60% 35-50 ppm 30-50 ppm 35-50 ppm 7-12 ppm 50-150 ppm 50+ ppm Nema-Q® High Performance Nematode Control If leaf analysis shows the nitrogen status of your trees is lower than the standards table says it should be, use this handy rule of thumb: For every 10 percent increase in nitrogen fertilizer applied, expect to raise leaf nitrogen by 0.1 percent, Cheng said. Control plant parasitic nematodes on contact with NEMA-Q, a highly effective and organically approved (OMRI listed) nematicide. Derived from botanical extracts Calcium With the increase in Honeycrisp plantings, growers have had to learn more about adjusting calcium levels. Honeycrisp is not the only bitter pit-susceptible variety, Cheng said. It joins Cortland, Jonagold, Mutsu, and Northern Spy, and even McIntosh can become sensitive as efforts increase to make larger fruit. Optimum leaf calcium levels range from 1.3 to 2 percent. Inadequate calcium can result from low soil pH, and boron or zinc deficiencies. Cheng recommends growers adjust soil pH before planting to make sure calcium supply is adequate. Growers should control tree vigor, since shoots and leaves compete with fruit for available calcium, and should avoid low crop loads, which can lead to bitter pit. For sensitive varieties, he recommends three to four sprays containing one to two pounds of calcium chloride per 100 gallons of water at 14-day intervals beginning a week to ten days after petal fall. Then apply two additional sprays with three to four pounds per 100 gallons four weeks and two weeks before harvest. www.goodfruit.com closely related to fruit yield, and growers should replace at least this amount to sustain tree productivity, Cheng said. Cheng and his colleague, Dr. Terence Robinson, at Cornell are working with Helena Chemical Company and apple growers in New York to test electrical conductivity measurement-based mapping techniques to develop variable rate of fertilizer and lime applications for more precise nutrient management in apple orchards. Water soluble and compatible with most water based pesticides and fertilizers Labeled for use on grapes, stone and pome fruits, nuts and vegetable crops Grow with Brandt.co The proud sponsor of the #31 Chevrolet driven by NASCAR Nationwide Series Championship contender Justin Allgaier. For more information, talk to your local BRANDT representative or PCA about NEMA-Q today. Brandt Consolidated, Inc. P.O. Box 35000 Fresno, California 93745 USA 559 499 2100 www.brandt.co GOOD FRUIT GROWER June 2013 9