Helping crops recover from waterlogging

It’s been a very wet winter in Northern Europe and winter cereal crops are looking stressed. In this article, we explore how waterlogging stress affects crops, and what we can do to help them recover.

What happens when cereals are waterlogged?

When roots are waterlogged, they have restricted access to oxygen due to soil pores filling with water. Oxygen diffuses through water 104 times slower than through air, and processes that need oxygen become restricted. Plants need oxygen to produce ATP in mitochondria, but in waterlogged soil not enough oxygen is available and plants switch to using fermentation to create ATP as the normal processes cease to work.

This method of synthesizing ATP (the plants’ main energy source) generates high levels of Reactive Oxygen Species (ROS), toxins that damage plant cells and reduce growth.

Elsewhere in the plant ROS synthesis increases in chloroplasts during stress events.

This increase in ROS during waterlogging damages plants. High levels of ROS can cause irreversible cellular damage by protein oxidation, enzyme inactivation, changes in gene expression, and decomposition of biological membranes resulting in cell death.

To counter the problem of ROS build-up, plants start to synthesize the stress hormone ethylene. This has the beneficial effect of ‘switching on’ mechanisms to protect the plant from ROS damage but also has negative effects. It removes calcium from cell walls leaving the crop more susceptable to disease and promotes chlorophyllase activity, an enzyme that destroys chlorophyll, reducing photosynthesis.
Yield is lost due to a combination of reductions in photosynthesis, growth rate, and tillering. Death of leaves, reduced spike formation (barley), and reduced fertile florets per spike (wheat).
The most damaging time however is immediately after the soil dries out. When roots become re-oxygenated trapped ethylene that has built up in roots is released as an ‘ethylene burst’ making the crop highly susceptable to disease ingress.

Research shows that Levity’s Indra can help cereal crops recover from waterlogging and flooding.

Indra is Levity’s anti-stress product, it aids recovery from waterlogging in three ways.

  • Stimulates production of polyamines, powerful cell wall protectants that repair the damage done to cell walls by ethylene.
  • Stimulation of anthocyanin synthesis, powerful antioxidants that protect against ROS damage.
  • A balanced supply of the nutrients needed to stimulate recovery of growth.

Here we present data from experiments carried out at Levity’s UK Research centre. Barley plants were grown in pots and submerged in water for 6 days, then treated with 1L/Ha Xerxes (Indra Plus) and assessed two weeks later.

Root length when treated with Xerxes was significantly improved, with roots better than the non-waterlogged control plants.

Tiller number in control was significantly reduced by waterlogging, but Xerxes treated plants maintained the same tiller number as the non-waterlogged control plants.
Waterlogging significantly reduced leaf number in untreated plants, but Xerxes treated plants maintained the same leaf number as the non-waterlogged control.
Shoot height was significantly reduced by waterlogging, but Xerxes treated plants reached the same height as the non-waterlogged control.

Perhaps the most interesting data of all though was growth rate. The waterlogged plants grew at the same rate as non-waterlogged control plants, but where Xerxes was applied the growth rate was significantly higher than both waterlogged and non-waterlogged controls.

This improved growth rate explains how after two weeks the Xerxes treated plants had caught up with the non-waterlogged plants, reversing the loss in growth.

Recommendations

Levity’s Indra range of anti-stress products all share the same chemistry

  • Indra
  • Indra Plus
  • Xerxes

For recovery from waterlogging foliar apply 1L/Ha as soon as possible post waterlogging. Repeat every 4 weeks to maintain improved growth.

Consider also applying 5L/Ha Lono for even better results.