By: Forrest Scharf (PAg) Provincial Specialist, Fruit Crops
Six iron fertilizer products were demonstrated at Canada Saskatchewan Irrigation Diversification Centre fruit plots in 2015, along with control plots and a humic acid/alfalfa pellet treatment. Fruit plots had been suffering from persistent iron chlorosis symptoms due to high pH soil combined with cool, wet conditions, limiting iron uptake in plants. Fruit productivity had been in severe decline, and many Saskatchewan fruit growers located in similar soils had similar experiences.
Iron products were demonstrated on Saskatoon berry, haskap and dwarf sour cherry orchard rows, with treatments randomized in an attempt to overcome bias from pre-existing plot variability. Iron treatments included foliar applied iron chelate and iron monohydrate, as well as soil applied iron chelate, iron sulfate, iron sucrate and iron monohydrate. The climate conditions in 2015 were dry and warm, and these conditions did not support development of iron chlorosis, so treatment effect was minimized.
Visual differences could be seen, but leaf analysis did not show significant differences in treatment effect. Fruit yield was above average in Saskatoon berry and dwarf sour cherry; however, negligible yield was obtained from haskap plots. Yield levels were not significantly correlated with treatment effect, nor were sugar content or fruit quality.
Saskatoon berry and dwarf sour cherry nutrient levels of N-P-K-S and iron were largely adequate in 2015. Dwarf sour cherry had deficient levels of zinc, according to apple nutrient standards, but this did not affect yield or fruit quality. Haskap nutrient content was determined to be deficient in a number of different nutrients, including N,K and zinc.
Haskap deficiencies likely relate to root conditions and other physiological conditions, rather than specific plant needs for these fertilizers. Plots were demonstrated July 9, 2015, at a field day with roughly 80 people in attendance, and results were presented at the Saskatchewan Fruit Growers Association Annual Conference in January 2016 (Crop Production Week).
The full ADOPT report is on the Agriculture Development Fund website.