The 2008 grazing season - Plenty of clouds, but no silver lining!

Although the persistent unsettled weather brought the grazing season to an abrupt end on many farms in mid/late September, the first snow of the winter in mid-October really finished off the season.  With the majority of farms already well settled into the winter routine, we can now reflect on the 2008 grazing season, and examine grass growth this year across Northern Ireland. The Agri-Search and DARD funded GrassCheck project monitored grass growth at six sites, with measurements taken in Antrim, Hillsborough, Loughgall, Portaferry, Fintona and Aghadowey.

The season began very slowly from a grass growth point of view, with difficult ground conditions a feature of most farms throughout March. The high soil moisture measurements taken across the sites, combined with the cold wet weather resulted in below average growth rates, with only the Portaferry site recording above average growth through March. The beginning of April however brought an increase in temperatures and some dry weather, and by mid-April ground conditions had improved considerably on most farms. However, despite the improved weather, only the Portaferry and Antrim sites achieved close to average growth through April, with growth at Fintona particularly poor at only 10 percent of normal by 14 April.

The generally dry and warm weather continued into May, with growth at all sites continuing to increase. Grass growth peaked on 12 May for the 4 sites in the east and south, with growth peaking at Fintona and Aghadowey on 26 May. Growth at this stage was very good, with the 141kgDM per ha per day recorded at Portaferry amongst the highest values ever recorded in the 9 years of the GrassCheck project. This phenomenal growth caused difficulties on many farms, with surplus grass being carried into mid-May, while others opted to remove some paddocks for a light cut of silage in early May.

Soil moisture again became a feature in mid/late-May, with the continuing dry weather having a negative effect on grass growth, particularly with regrowths on the drier soils. Weather records at AFBI, Crossnacreevy indicate that the monthly rainfalls for April and May were 65 and 80 percent below the long term average, respectively (1990 - 2007).

The dry weather in May had a dramatic effect on grass growth in June, with all sites recording below average production for most of the month. Soil moisture deficits recorded at Hillsborough, Antrim, Loughgall and Portaferry limited grass production from mid-May to late-June. Despite grass supplies being tight, many farmers were able to achieve high levels of grass utilisation, given the excellent ground conditions, and grass quality in general was very good at this stage of the season.

Growth rates in June were poor at 64 percent below average at Hillsborough, and with the exception of 1 week in Portaferry, June grass growth was below average across the six sites. This period of dry weather had a particularly detrimental impact on grass growth at the Loughgall site, with soil mositure in severe deficit from 23 May until 16 June. This had a major impact on growth at this stage, and also, due to die back of the sward, had a continued detrimental effect through the rest of the year.

Growth across the sites improved through early July as a result of increased rainfall, but it wasn’t until the second half of the month that growth reached, and in most cases exceeded the long term average. The July rainfall recordings were 50 percent above average, and began to impact on grazing and ground conditions on heavier soils by the end of the month. The wet weather continued into August, and by the middle of the month most farms were struggling with difficult ground conditions. Despite these extremely wet conditions, growth rate remained high through early August at all sites. However, following over 2.5 times the average rainfall in August, growth rates at the sites at Aghadowey and Fintona fell below average. The drier sites at Antrim, Hillsborough and Portaferrry continued to produce above average growth throughout August, with growth in Portaferry being 39 percent above average during this period.

With challenging and in some cases water logged ground conditions across Northern Ireland at the beginning of September, the persistent rainfall resulted in the housing of many herds. Continuing the trend of the summer months, total rainfall during September was 75 percent higher than average, with October rainfall 23 percent higher. Management of grazing swards through late September and early October is very important for the preparation of the next seasons grazing, but many farms faced very difficult conditions at this stage, with short periods of grazing broken up by periods of housing. In reality most farms were carrying too much grass to close up, and with the milking cows housed, most farmers had to use dry stock to prepare the grazing swards for spring 2009.

Although 2008 was a very difficult year for grassland (and other crops), there was considerable variation in total grass production across Northern Ireland. The extremes in the weather resulted in below average production (10.9t DM per ha) on half the sites, with only Antrim at 11.7t DM per ha and Portaferry at 12.9t DM per ha above the annual average. The heavier soils in Fintona and Aghadowey restricted total grass production to 9.9 and 10.1t DM per ha respectively.

Andrew Dale discussing the final arrangements for preparing the grazing swards for 2009 with Maite Oiartzun and Ashley Stewart at AFBI, Hillsborough