Project Update - Improving efficiency from grass at Rhiwaedog demonstration site
There are various elements involved in the improving efficiency from grass project at Rhiwaedog. A grazing trial was conducted during spring 2020 focusing on the benefits of using standard versus protected urea. Protected and standard urea was applied to separate grass plots on 11 April 2020 at a rate of 35kg per acre, therefore supplying 32 units of nitrogen per acre (40kgN/ha). Ground conditions delayed earlier application as temperatures were considered high for standard urea application (12°C). This was followed by a lack of rain post application. The outcome of this trial concluded that using protected urea this spring lead to an estimated 30% increased grass growth (2,100kgDM/ha from standard urea versus 2,800kgDM/ha from protected urea).
4 weeks post urea application:
Another element of the project includes comparing grass silage yields from plots treated with ammonium nitrate versus protected urea. On 15 May 2020, 75kg per acre of protected urea was applied on one plot, as well as 100kg per acre of ammonium nitrate (69 unitsN/acre) on a separate plot. Fertilisers were applied on very dry round conditions and in overcast conditions.
Following a yield assessment on 22 June 2020, grass yields of plots given protected urea were calculated at 4,120kgDM/ha, whilst plots given ammonium nitrate were calculated at 5,050kgDM/ha. It was determined that using protected urea on silage crops reduced grass growth by around 20%. This is most likely due to prolonged dry conditions (15+ dry days) breaking down the protective layer on the protected urea. The next aspect of the project will involve increasing sward quality by introducing multispecies leys.