Tillage: Winter rains pose big fertiliser issues
Published 09/03/2016 | 02:30
February is usually one of the driest months of the year. However, February this year gave 109mm of rain at my local Met station in Gurteen, Co Tipperary. This exceeded the maximum monthly rainfall since records commenced in Gurteen in March 2008.
We have also experienced the heaviest winter rainfall in recent years. Met Eireann described this winter as being wetter and milder than normal everywhere. Rainfall at all their monitoring stations was above their long term average and over half their stations reported the wettest winter on record.
It is likely that the mild winter has resulted in greater disease levels surviving in crops over the winter.
Disease control strategies will have to be planned carefully so as to keep both disease resistance and fungicide cost under control. A mild winter would also be likely to result in high levels of aphid transmitted virus.
However, rainfall levels appear to have kept aphid populations suppressed. In general winter barley crops looked surprisingly well up to the last week in February when many of them went yellow almost overnight.
The way land manages water is largely dependent on the soil topography and drainage characteristics. On free draining soils most of that rain moves down through the soil into groundwater; lands with poorer drainage are subject to run-off, over-land flow, or flooding.
Movement of water down through the soil profile is likely to carry nutrients and silt with it. Over-land flow will carry clay particles and the nutrients attached to the clay.
The big question now is do we need to adjust our fertiliser management programmes to allow for the increased winter rainfall? We generally associate fertiliser programmes with supplying the nutrients required for plant growth. What is equally important is the fact that most, if not all, nutrients impact on plant disease risk.