Preparing for tree crop recovery on the North Coast

09 Sep 2022

North Coast Landholders impacted by both the floods and the subsequent ongoing wet conditions have frequently experienced waterlogging of soils - managing these impacts has been a primary focus for many tree crop growers across the region.

With the seasonal outlook now predicting a wetter than average spring, it is important for tree crop growers to prepare for further inundation of crops.

Whilst improving drainage to get water off paddocks may have been a short-term solution, long term planning for wet conditions is becoming increasingly important with the long-term weather forecast.

Options to improve drainage might include re-shaping the layout of the field, improving surface drainage or installing subsurface drainage.

Waterlogged soils are deficient in oxygen because the oxygen between soil particles is replaced by water. Oxygen is essential for healthy root growth - insufficient oxygen in soils over time leads to the death of the plant.

Tree crops can survive without oxygen to the roots for longer than most vegetables and flowers, however, the longer soils remain saturated, the more likely root death will occur.

Stagnant water, particularly if it is shallow, can heat up in hot sunny weather and kill plants in a few hours. Removing excess water as soon as possible after flooding and managing drainage to remove areas where water can pool is critical to plant survival.

Soils with a high clay content can become compacted and form a surface crust after heavy rainfall and flooding and flood waters also deposit a fine clay layer or crust on top of the soil which prevents oxygen penetration into the soil (aeration). This crust layer should be broken up and incorporated into the soil profile as soon as possible.

In some circumstances flood waters may have contained chemical and biological contaminants, however they will have reduced over time and with follow-up rainfall and sunny weather.

Additionally, increased incidence of secondary root disease, such as Phytophthora Root Rot, are often observed where soil conditions are saturated.

Growers should be aware of increased disease risk in these conditions and apply suitable prevention or treatment options where required.

Some areas will not withstand ongoing soaking and if drainage cannot be improved, growers should consider using the area for some other purpose, such as a silt trap.

Our Sustainable Agriculture team can help landholders access information about removing or replacing crops damaged due to water logging, fertiliser application and soil management. Contact North Coast Local Land Services on 1300 795 299.