b'TreatmentsThe chemical P was weighed in the lab before application. Cattle slurry was weighed on-site,adjusted for volume using a slurry hydrometer and sub-samples were sent to an accredited laboratory for analysis of N, P, K and DM content. The same rate of P (42 kg/ha) was applied to each plot over the year using a split application of 21 kg/ha in both April and June. This mimicked typical P applications across the growing season for a silage cut based system (Wall andPlunkett, 2016). Supplementary applications of N and K insured equal distribution of nutrients across the plots and prevented nutrient deficiencies from occurring.Water samplingTo obtain pore water samples, each tube was equipped with a syringe and suction wasmaintained for 2-3 days. Each sample was then, collected from the plots, bulked, andfiltered in the lab (0.45 microns) prior to analysis. The samples were analysed for DRP, TP, N-NH 4and TON.Sampling was conducted on a monthly basis throughout the growing season (February to September) of the year 2019, and each probe was sampled once a month, prior to grass harvests. During the initial weeks of the 2018 closed period (October to December), a higher sampling resolution was implemented. In this period, sampling was conducted weekly. During 2019, weekly sampling was conducted over the 3 weeks subsequent to each slurry application (May, July and October), and for the first weeks of the closed period (up to December). ReferencesAnonymous. 2015. FoodWise 2025A 10-year vision for the Irish agri-food industry. Department of Agriculture Food and the Marine, Dublin https://www.agriculture.gov.ie/foodwise2025/Dodds, W. K., and V. H. Smith. 2016. Nitrogen, phosphorus, and eutrophication in streams. Inland Waters, 6, 155-164.Morgan, M. 1941. Chemical soil diagnosis by the universal soil testing system. Bull. 450.Connecticut Agric. Exp. Stn., New Haven. Chemical soil diagnosis by the universal soil testing system. Bull. 450. Connecticut Agric. Exp. Stn., New Haven.ONeil, J., T. Davis, M. Burford, and C. Gobler. 2012. The rise of harmful cyanobacteria blooms: the potential roles of eutrophication and climate change. Harmful algae, 14, 313-334.OJEC, 1991. Council Directive 91/676/EEC Concerning the Protection of Waters against Pollution Caused by Nitrates from Agricultural Sources. Wall, D., and M. Plunkett. 2016 Major and Micro nutrient advice for productive agricultural crops. Teagasc Environment Research Centre, Johnstown Castle, Wexford, p 175.89'