By Blake Jackson
It might seem unusual, but the excessive rainfall many areas of Missouri experienced this year could make plants, trees, and shrubs more vulnerable to drought stress later in the season.
Healthy plants depend on strong root systems to absorb water and nutrients from the soil and transfer them to the leaves, where energy is produced through photosynthesis.
When soil becomes oversaturated with rainwater, the essential oxygen that roots rely on is pushed out of the soil’s pores.
“The roots of plants need oxygen to respire just like you and I need oxygen,” said David Trinklein, horticulture state specialist with University of Missouri Extension. “When it rains a lot, the pores in the soil that had contained oxygen are filled with water. Thus, the roots become oxygen-deprived, at times to the point of death,” he said.
Even if the roots manage to survive, extended exposure to waterlogged conditions weakens them, increasing their susceptibility to root rot and other anaerobic diseases.
Deep roots, particularly in woody plants like trees and shrubs, are typically the first to suffer under saturated conditions. Shallow roots near the surface fare better, as oxygen is more available in that zone.
This issue also affects plants established during the spring. Since water and air were abundant in the upper soil layers, their roots remained shallow and didn’t develop the depth needed to access moisture during dry spells.
As temperatures rise and rain slows, the topsoil dries out rapidly, potentially leading to drought stress despite the overall rainfall being higher than average.
“It is best to water thoroughly but infrequently,” Trinklein recommended. “This will encourage roots to follow the water to the lower profile of the soil. It also will promote the development of deep root systems, which plants need to stay healthy.”
To better prepare soil for wet or dry conditions, Trinklein advises incorporating well-decomposed organic matter. “Organic matter also creates large soil pores filled with oxygen-laden air,” he said, adding that it helps improve soil structure and water movement.
With careful management, gardeners can help plants weather both the floods and droughts Missouri’s climate can deliver.
Photo Credit: pexels-greta-hoffman
Categories: Missouri, Crops, Weather