Transitioning to low chemical nitrogen perennial ryegrass white clover pastures on wetland grazing dairy systems
H. Walsh
A B * , D. Patton A , J. J. Collins A , L. Delaby C , K. Pierce B and B. Horan A
A
B
C
Abstract
Reductions in chemical nitrogen fertiliser applications in agricultural systems within the European Union will have a significant role in reducing greenhouse gas emissions related to agriculture.
The current study investigates the transition from old permanent perennial ryegrass (PR) swards (PR-old) to newly established PR (PR-new) receiving high levels of chemical nitrogen (N) application or PR white clover swards (PRWC) receiving lower levels of chemical N application on wetland soils in the border, midland and western region of Ireland over 3 years (2021–2023, inclusive).
The experimental site, which consisted of old PR swards, was transitioned to either new PR swards receiving up to 250 kg N/ha per annum or PRWC swards receiving up to 125 kg N/ha annually.
In the year of establishment, PR-new and PRWC-new swards has a significantly reduced total pasture DM yield (8925 and 8561 kg DM/ha) compared to older PR swards (14,182 kg DM/ha) while PRWC oversown (PRWC-over) swards were intermediate (11,330 kg DM/ha). In subsequent years, PR-new, PRWC-new and PRWC-over swards achieved increased DM yield (14,891, 15,642 and 15,218 kg DM/ha) compared to older swards. Within PRWC, white clover contents increased from 0 g/kg DM in early 2021 to 250 and 190 g/kg DM in 2022 and 2023, respectively. Consequently, significant reductions in chemical N fertiliser applications were achieved, from 229 and 200 kg N/ha for PR-old and PR-new swards, respectively, and 124 and 84 kg N/ha for PRWC-over and PRWC-new swards, respectively. The PRWC system tended (P < 0.08) to have increased milk and milk fat plus protein yield (5197 and 473 kg/cow, respectively) compared to the PR (5092 and 461 kg/cow, respectively) during the 3 year study period.
These results highlight the potential for PRWC systems to increase pasture production and milk production, while reducing chemical N applications in comparison to PR only systems on a wetland soil.
The extent of sward renewal and initial reduction in pasture production may result in shortages in winter feed production during the transition to low chemical N PRWC systems.
Keywords: chemical nitrogen, dairy cow, dairy grazing systems, pasture production, perennial ryegrass, wetland soils, white clover, white clover establishment.
References
Chapman DF, Lee JM, Rossi L, Edwards GR, Pinxterhuis JB, Minnee EMK (2017) White clover: the forgotten component of high-producing pastures? Animal Production Science 57, 1269-1276.
| Crossref | Google Scholar |
Clavin D, Nolan S, Humphreys J (2017) Introducing white clover into existing swards and getting variety choice right. Available at https://www.teagasc.ie/media/website/publications/2017/8-Introducing-white-clover-into-existing-swards-and-getting-variety-choice-right.pdf [verified 14 February 2025]
Creighton P, Kennedy E, Shalloo L, Boland TM, O’Donovan M (2011) A survey analysis of grassland dairy farming in Ireland, investigating grassland management, technology adoption and sward renewal. Grass and Forage Science 66, 251-264.
| Crossref | Google Scholar |
DAFM (2020) Publication of “Ag Climatise” – National Climate & Air Roadmap for the Agricultural Sector. In: Climate neutral agriculture by 2050. Available at https://www.gov.ie/en/press-release/a8823-publication-of-ag-climatise-national-climate-air-roadmap-for-the-agriculture-sector/ [verified 12 January 2024]
DECC (2021) Climate action plan 2021. Available at https://www.gov.ie/en/publication/6223e-climate-action-plan-2021/ [verified 19 December 2023]
Dineen M, Delaby L, Gilliland T, McCarthy B (2018) Meta-analysis of the effect of white clover inclusion in perennial ryegrass swards on milk production. Journal of Dairy Science 101, 1804-1816.
| Crossref | Google Scholar |
Egan M, Galvin N, Hennessy D (2018) Incorporating white clover (Trifolium repens L.) into perennial ryegrass (Lolium perenne L.) swards receiving varying levels of nitrogen fertilizer: effects on milk and herbage production. Journal of Dairy Science 101, 3412-3427.
| Crossref | Google Scholar |
Enriquez-Hidalgo D, Gilliland TJ, Hennessy D (2016) Herbage and nitrogen yields, fixation and transfer by white clover to companion grasses in grazed swards under different rates of nitrogen fertilization. Grass and Forage Science 71, 559-574.
| Crossref | Google Scholar |
FAO (2023) The state of food security and nutrition in the world. Food and Agriculture Organisation of the United Nations. Available at https://www.fao.org/3/cc3017en/online/cc3017en.html [verified 18 February 2024]
Frame J (1987) The effect of strategic fertilizer nitrogen and date of primary harvest on the productivity of a perennial ryegrass/white clover sward. Grass and Forage Science 42, 33-42.
| Crossref | Google Scholar |
Glassey CB, Roach CG, Lee JM, Clark DA (2013) The impact of farming without nitrogen fertiliser for ten years on pasture yield and composition, milksolids production and profitability; a research farmlet comparison. Proceedings of the New Zealand Grassland Association 75, 71-78.
| Crossref | Google Scholar |
Government of Ireland (2021) Food vision 2030. Available at https://www.gov.ie/pdf/?file=https://assets.gov.ie/179717/910771f6-05ed-43f1-b8ce-52ef7c602710.pdf#page=null [verified 18 February 2024]
Grace C, Boland TM, Sheridan H, Lott S, Brennan E, Fritch R, Lynch MB (2018) The effect of increasing pasture species on herbage production, chemical composition and utilization under intensive sheep grazing. Grass and Forage Science 73, 852-864.
| Crossref | Google Scholar |
Guy C, Hennessy D, Gilliland TJ, Coughlan F, McClearn B, Dineen M, McCarthy B (2018) Comparison of perennial ryegrass, Lolium perenne L., ploidy and white clover, Trifolium repens L., inclusion for herbage production, utilization and nutritive value. Grass and Forage Science 73, 865-877.
| Crossref | Google Scholar |
Hoogendoorn CJ, Holmes CW, Chu ACP (1992) Some effects of herbage composition, as influenced by previous grazing management, on milk production by cows grazing on ryegrass/white clover pastures. 2. Milk production in late spring/summer: effects of grazing intensity during the preceding spring period. Grass and Forage Science 47, 309-404.
| Crossref | Google Scholar |
Hume DE, Chapman DF (1993) Oversowing of five grass species and white clover on a Taupo hill country pumice soil. New Zealand Journal of Agricultural Research 36, 309-322.
| Crossref | Google Scholar |
Humphreys J, Lawless A (2006) A guide to management of white clover in Grassland – Moorepark dairy research update. Available at https://www.teagasc.ie/media/website/animals/dairy/MPK-Dairy-Levy-Update-Series-3.pdf [verified 6 April 2024]
Humphreys J, Casey IA, Laidlaw AS (2009) Comparison of milk production from clover-based and fertilizer-N-based grassland on a clay-loam soil under moist temperate climatic conditions. Irish Journal of Agricultural and Food Research 48, 189-207.
| Google Scholar |
ICBF (2020) Understanding the Economic Breeding Index (EBI). Available at https://www.icbf.com/wp-content/uploads/2020/02/Understanding-EBI-PTA-BV-Spring-2020.pdf [verified 6 April 2024]
ISB (2009) S.I. No. 101 of 2009 - European Communities (Good Agricultural Practice for Protection of Waters) Regulations 2009. Available at https://www.irishstatutebook.ie/eli/2009/si/101/made/en/pdf [verified 21 March 2024]
Jørgensen M, Bakken AK, Østrem L, Brophy C (2023) The effects of functional trait diversity on productivity of grass-legume swards across multiple sites and two levels of nitrogen fertiliser. European Journal of Agronomy 151, 126993.
| Crossref | Google Scholar |
Kennedy E, O’Donovan M, Murphy JP, O’Mara FP, Delaby L (2006) The effect of initial spring grazing date and subsequent stocking rate on the grazing management, grass dry matter intake and milk production of dairy cows in summer. Grass and Forage Science 61, 375-384.
| Crossref | Google Scholar |
Leach KA, Bax JA, Roberts DJ, Thomas C (2000) The establishment and Performance of a Dairy System based on Nitrogen Fertilised Grass. Biological Agriculture & Horticulture 17, 207-227.
| Crossref | Google Scholar |
Lüscher A, Mueller-Harvey I, Soussana JF, Rees RM, Peyraud JL (2014) Potential of legume-based grassland-livestock systems in Europe: a review. Grass and Forage Science 69, 206-228.
| Crossref | Google Scholar |
McDonagh J, Gilliland TJ, McEvoy M, Delaby L, O’Donovan M (2017) Nitrogen and white clover impacts on the management of perennial ryegrass-clover swards for grazing cattle. The Journal of Agricultural Science 155, 1381-1393.
| Crossref | Google Scholar |
McEvoy M, O’Donovan M, Shalloo L (2011) Development and application of an economic ranking index for perennial ryegrass cultivars. Journal of Dairy Science 94, 1627-1639.
| Crossref | Google Scholar |
Met Éireann (2024) Historical data. Available at https://www.met.ie/climate/available-data/historical-data [verified 15 February 2024]
Ribeiro Filho HMN, Delagarde R, Peyraud JL (2005) Herbage intake and milk yield of dairy cows grazing perennial ryegrass swards or white clover/perennial ryegrass swards at low- and medium-herbage allowances. Animal Feed Science and Technology 119, 13-27.
| Crossref | Google Scholar |
Schwinning S, Parsons AJ (1996) A spatially explicit population model of stoloniferous N-fixing legumes in mixed pasture with grass. Journal of Ecology 84, 815-826.
| Crossref | Google Scholar |
Scully KM, Keogh B, O’Brien B, Casey IA, Humphreys J (2021) The effect of fertilizer nitrogen input to grass-clover swards and calving date on the productivity of pasture-based dairy production. Journal of Dairy Science 104, 8870-8884.
| Crossref | Google Scholar |
Søegaard K (2009) Nitrogen fertilization of grass/clover swards under cutting or grazing by dairy cows. Acta Agriculturae Scandinavica, Section B – Soil & Plant Science 59, 139-150.
| Crossref | Google Scholar |
Teagasc (2014) Moorepark dairy levy research update – pocket manual for reseeding. Available at https://www.teagasc.ie/media/website/animals/beef/pocketmanualforreseeding.pdf [verified 23 March 2024]
Teagasc (2024) Nitrates and derogation. Available at https://www.teagasc.ie/environment/schemes--regulations/nitrates-derogation/
Ulyatt MJ (1970) Evaluation of pasture quality under New Zealand conditions. New Zealand Grassland Association 32, 61-68.
| Crossref | Google Scholar |
Walsh H, Patton D, Collins JJ, Pierce K, Horan B (2024) Futureproofing Irish dairy farms – transitioning to low chemical nitrogen perennial ryegrass white clover swards on wetland grazing dairy systems. Available at https://www.teagasc.ie/media/website/publications/2024/Ballyhaise-Open-Day.pdf [verified 21 February 2025]
