The national fodder crisis is back in the main stream news- with reports of grass growth 50% below normal and silage stores nearly empty.
But this crisis has been developing since summer last year and has crept across the country from the north west to the south east.
The main reason is the seemingly relentless rain and low temperatures. The rainfall problem is characterized not so much as excess rain (though accumulated rainfalls are above normal) but by its remorselessness – it has rained continually so that some places haven’t seen two dry consecutive days since last year, so soils haven’t had a chance to dry. Soils that are very wet cannot be trafficked without damaging them, – so many farmers were unable to get the usual harvest of silage toward the end of the summer, so stores were low. The rain continued so farmers had no option but to bring cattle indoors and feed them the stored fodder (cattle can do as much damage to wet soils as a tractor).
Unfortunately the rain continued which meant animals has to stay indoors and this coupled with a cold late spring has meant that across the country grass has not started to grow. This effect of a cumulative seasonal impact (wet autumn, cold spring) is being studied by one of our PhD students Mohana Logakrishnan- who is looking at historical weather , satellite and farm records to build a model that can predict what the final economic impact of the current conditions will be at the end of the year.
Another student, Richa Marwaha is building a national biomass estimator using satellites so we can measure the amount of grass growing in the country and be able to estimate what the national fodder harvest each year is. One of her outputs is February’s map of the month.
Our newest PhD student Azucena Castaneda is studying ways of improving the calibration of Met Eireann’s rainfall radar, so we can get real time estimates of current and cumulative rainfall at any location in the country. These will be combined with Sentinel 1 images to see if we can estimate soil moisture/SMD.
Finally our fourth student working in the area is Rob O’Hara and he is using satellites to measure the extent and effectiveness of field drainage. Obviously the impact of rainfall on soils varies with the soils capacity to drain the water away. If you are farming in an area of “heavy soils” then the drainage can be improved though the installation of drains (either ditches or underground drains) and Rob’s work has used Sentinel and Landsat to distinguish drained and un-drained fields and to look at the impact on grass growth of drains.
One of his outputs, actually looking at the recovery time of grassland after inundation/flooding, shows how, even if spring arrives with a bang it’ll be weeks before some farms, especially on un-drained fields in the BMW region will be back to “normal”.
This plot using NDVI as a proxy for grass growth (for non-remote sensors, the higher the value, the more grass is growing) looks at fields inundated in the floods of 2015/16. What this tells us is that fields still flooded after Feb 11th had lower grass growth in May, June and July than expected- and at the extreme, fields that only drained by April 11th had very reduced grass growth in May and still reduced growth in June. So farms that have been inundated for long period, as many in the NW have – will still be feeling the effects on grass growth in June this year, even if the weather picks up by mid April. This sort of impact will have knock-on effects on farm management for the rest of the year and could potentially leave these farms vulnerable next winter to even a relatively mild seasonal shock.