Management to reduce the impact of waterlogging in crops

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Drainage is usually the best way of reducing waterlogging. Other management options to reduce the impact of waterlogging include: choice of crop, seeding, fertiliser and weed control.

Choice of crop species

Some species of grains crop are more tolerant than others. Grain legumes and canola are generally more susceptible to waterlogging than cereals and faba beans.

Seeding crops early and using long-season varieties help to avoid crop damage from waterlogging. Crop damage is particularly severe if plants are waterlogged between germination and emergence. Plant first those paddocks that are susceptible to waterlogging. However, if waterlogging delays emergence and reduces cereal plant density to fewer than 50 plants/m2, resow the crop.

Seeding rates

Increase sowing rates in areas susceptible to waterlogging to give some insurance against uneven germination, and to reduce the dependence of cereal crops on tillering to produce grain. Waterlogging depresses tillering. High sowing rates will also increase the competitiveness of the crop against weeds, which take advantage of stressed crops.

Nitrogen fertiliser

Crops tolerate waterlogging better with a good nitrogen status before waterlogging occurs. Applying nitrogen at the end of a waterlogging period can be an advantage if nitrogen was applied at or shortly after seeding because it avaoids loss by leaching or denitrification. However, nitrogen cannot usually be applied from vehicles when soils are wet, so consider aerial applications.

If waterlogging is moderate (7–30 days waterlogging to the soil surface), then nitrogen application after waterlogging events when the crop is actively growing is recommended where basal nitrogen applications were 0–50kg N/ha.  However, if waterlogging is severe (greater than 30 days to the soil surface), then the benefits of nitrogen application after waterlogging are questionable.  But this recommendation requires verification in the field at a range of basal nitrogen applications using a selection of varieties.

Weed density affect a crop's ability to recover from waterlogging. Weeds compete for water and the small amount of remaining nitrogen, hence the waterlogged parts of a paddock are often weedy and require special attention if the yield potential is to be reached.

Contact information

Derk Bakker
Page last updated: Friday, 20 March 2015 - 8:29am