Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2025
Publication Date: 2/15/2025
Citation: Farqani, A.A., Fazio, G., Cheng, L., Robinson, T.L. 2025. Effects of Soil pH on Growth, Early Fruiting and Mineral Nutrient Profile of ‘Honeycrisp’ Apple Trees Grafted on Eight Rootstocks.. Scientia Horticulturae. https://doi.org/10.1016/j.scienta.2025.114029.
DOI: https://doi.org/10.1016/j.scienta.2025.114029

Interpretive Summary: All soils feature unique levels of acidity/alkalinity (pH) which influence the availability of nutrients to roots. Apple trees grown in different soil types are also subject to varying pH levels and according to what rootstock they are grafted on they differ in how they are able to grow and produce good quality apples. In this experiment we tested Honeycrisp apple trees grafted on seven different rootstocks and found that low pH overall was not conducive to good apple growth and that certain rootstocks were better able to grow well in a wide range of pH levels. Certain rootstocks were also better at taking up certain nutrients like boron, phosphorous, calcium and magnesium. Knowing what rootstocks are well adapted to different soil pH levels is important in the establishment and management of productive and sustainable apple orchards.

Technical Abstract: Soil pH affects apple tree growth and fruit quality due to its effects on nutrient uptake. In this study, eight apple rootstocks (Geneva® G.11, G.41, G.935, G.202, G.214, Malling (M) M.9T337, M.26EMLA, and Budagovsky (B.9)grafted with ‘Honeycrisp’ apple cultivar were grown in 55 L pots with the soil pH adjusted to 5.0, 6.5 and 8.0. at Ithaca NY for two growing seasons from 2017 to 2018. Soil pH had a significant effect on tree growth with the best growth at the highest pH. Soil pH affected fruit peel nutrient concentrations of P, Ca, Mg, Fe, S, B, and Zn. Leaf nutrients concentrations were also affected by soil pH with low pH resulting in higher values of K, Ca, Mg, S, Fe and Mn and higher soil pH resulting in higher values for P and Zn. Fruit quality indices including total soluble solids, fruit’s firmness and bitter-pit incidence measured after 5 months of storage were unaffected by soil pH. However, greater fruit size was found at higher pH. Among rootstocks, G.935 had the greatest TCSA increase whereas B.9 had the smallest TCSA increase. The highest fruit number per tree in the second season was with G.41 and the lowest bitter pit % was with G.935. G.11 had the largest fruit size while G.935 had the best fruit red skin color. There were no significant interactions between rootstock genotype and soil pH on tree growth but there were several significant interactions of soil pH and rootstock genotype on leaf mineral concentrations and fruit quality.