We are now about a month into our Soil Moisture monitoring runs, and there has been some interesting results coming through following our wet winter and early spring.
The root systems have experienced flooded, anaerobic conditions, as the soils have been saturated for a long time and and only just starting to dry out. In some heavier soils, the subsoil continues to be at or above field capacity. Thus, deeper root systems may have minimal development due to being in poor growing conditions for such a long time and as a result, may not be operating at optimum coming into the growing season.
The La Nina weather system which delivered us a very wet few months, looks like it will weaken coming into the new year. Therefore, having a good overview on the behaviour of our soils as they start to dry out will be useful to ensure your trees have adequate available water.
Root systems are not at their healthiest following this winter period. Thus, coming into summer, poor development may cause drought symptoms in trees to occur more quickly than expected, as they have limited ability to access underground water reserves.
The two graphs below show a heavier and a lighter soil, where both are flooded at depth, but drying out in the top. In the two different soils, the top 200mm has been below the trigger point for almost 2 weeks. It will be interesting to note how this has changed following the showers experienced since the last readings.
Figure 1 A lighter soil, with the profile graph showing flooding at depth, but drying out in the top.
Figure 2 A heavier soil, very wet below 300mm, but drying out in the top.
Sarah de Bruin – AgFirst
