Chapter authors - Ron Godin, Grant Cardon, Tony McCammon
Proper fertility management is necessary to maintain fruit tree productivity, maximize the quality and health benefits of the fruit, and optimize the profits for the producer and processor. It is important to conduct regular soil and foliar nutrient testing to determine excesses or deficiencies.
Soil and Leaf Analyses
Soil analyses are useful for determining mineral nutrient availability in soil before orchard establishment. For existing orchards, a soil test every three years provides useful information for interpreting leaf analysis results and modifying fertilization programs.
Leaf analysis indicates the concentration of nutrients that are actually present in the tree foliage. If leaf samples are taken correctly and the results are interpreted properly, they provide a good tool for developing an effective fertilization program. Leaf samples should be collected about 60 to 70 days after petal fall, which generally corresponds to late July or early August. Undamaged leaves about twelve nodes downward from the terminal end of shoots will provide the most representative sample. Each sample should consist of about 100 leaves collected from several trees in the sample area.
Do not mix leaves from different varieties, soil conditions, tree vigor, or crop load. Record observations on terminal shoot length, thickness, crop load, and fruit size, because these will enable meaningful interpretation of the observed nutrient concentrations in tree leaves.