Fertilizer decisions for fruit crops should be made based on scientific evidence of need. This is accomplished by combining results of foliar tissue and soil testing, with environmental conditions and crop load to develop a fertilizer program.
Foliar tissue analysis indicates the levels of macro and micro nutrients within the plant tissue. Standards have been established for tree fruit.
Foliar tissue collection timing: 60 to 70 days after Petal Fall. Collect 70 to 100 of the most recent mature leaves from trees of the same variety. All labs use the sample testing method. Suggested sampling frequency is every year.
A soil analysis indicates the levels of macro nutrients (not nitrogen) and some micro nutrients available in the soil, as well as soil pH.
Soil sample collection timing: anytime the soil is not frozen. One sample will cover 10 acres unless there are changes in topography, previous fertility practices across the area have not been uniform, and if crops vary. Sample every 3 years. There are three different soil testing methods (Morgan, Modified Morgan and Mehlich 3). All are correct. However, in order to compare a field from one testing to another, use the same soil testing lab each time.
apple nutrient foliar standards
2.2 to 2.4 % Hard (firm-fleshed) varieties
1.8 to 2.2 % Soft varieties
2.4 to 2.6 % Non-bearing
|Phosphorus (P)||0.08 to 0.33 %|
|Potassium (K)||1.2 to 1.8 % (higher end for Empire)|
|Calcium (Ca)||1.3 to 2.0 %|
|Magnesium (Mg)||0.35 to 0.5 %|
|Boron (B)||35 to 50 ppm|
|Iron (Fe)||60 to 400 ppm|
|Manganese (Mn)||35 to 135 ppm|
|Copper (Cu)||7 to 12 ppm|
|Zinc (Zn)||25 to 50 ppm|
|soil optimum nutrient levels (modified morgan)|
6.5 to 7.0 (Non-bearing)
6.0 to 6.5 (Established)
9 lb (Established)
|Potassium (K)||240 lb|
|Calcium (Ca)||2400 lb|
|Magnesium (Mg)||400 lb|