• Philip

Waterlogging 2

Updated: 2 days ago

#winterwheat #wheat #slugs #blackgrass #seed #wintercropping #winter #cropping #clay #drainage #water #economics #farmadvice

I have been walking a large area of winter wheat this autumn looking for slugs, blackgrass and many other nasties.

The one common observation I would make is the effect of excess rainfall on field appearance. In some cases seed has died, in others growth has been restricted.

Over the last decade the number of water logging episodes I experience has increased. Is this due to more intense and unpredictable rainfall events or something more?

Winter cropping is commonly associated with soils of a high clay content and that compacted by the repeated use of heavy machinery. Such fields then experience poor drainage resulting in a water logging event.

To illustrate the economic losses associated with water logging is easy.

One 20 ha field – 7.4 t/ha of Winter wheat sold at £120/t = £888.00

A loss of 10% through water logging £88.00/ha or £1760.00 for the field.

What is happening to cause this? Simply, oxygen starvation.

Soil water logging imposes a considerable slow-down of the oxygen exchange between soil and roots, as gas diffusion rates are 10,000 times slower in water than in air. Consequently, waterlogged soils can quickly become anoxic at depths greater than a few centimetres, as the oxygen demand by roots and soil microorganisms’ respiration largely exceeds the influx from the atmosphere.

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