Seasonal soil waterlogging influences water relations and leaf nutrient content of bearing apple trees
1989
Olien, W.C.
Bearing 'Macspur'/M.26 apple trees (Malus domestica Borkh.) were grown in plastic-lined basins under orchard conditions. Four treatments were imposed in each of 3 years consisting of controls and 6-week periods of soil waterlogging in the spring, summer, or fall. Stomatal conductance, transpiration rate (E), leaf water content (LWC), and stem water potential were measured at the end of waterlogging period. Stomatal conductance was significantly reduced by spring and summer waterlogging, but not by fall waterlogging. Reduction in stomatal conductance and E generally increased over years. Stem water potential after spring and fall waterlogging averaged 8% less negative than controls in all 3 years, with no trend over the 3 years. In contrast, stem water potential of summer-waterlogged trees was unaffected, 45% was more negative, and 31% less negative than controls in the first, second, and third year of treatment, respectively. Annual reductions in growth and yield due to the waterlogging treatments were related to decreased stomatal conductance and to both negative and positive changes in stem water potential. Leaf levels of N, P, K, and Cu measured in July were reduced only by summer waterlogging, with no trend in response over years.
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