File(s) not publicly available

Implications of grass–clover interactions in dairy pastures for forage value indexing systems. 1. Context and rationale

journal contribution
posted on 2023-05-03, 12:30 authored by David Chapman, Julia Lee, Laura Rossi, Gerald CosgroveGerald Cosgrove, David StevensDavid Stevens, Jim CrushJim Crush, Warren KingWarren King, Grant Edwards, Alison PopayAlison Popay
The development of economic indexing systems for ranking cultivars of forage species requires new knowledge of factors that may influence the scaling of agronomic data collected in controlled, small-plot evaluation trials to whole farm systems. In the case of perennial ryegrass indexing, one such knowledge gap is the effect of growing clover with ryegrass on the relative rankings of different ryegrass cultivars. The objective of the investigation reported in this series was to test whether the relative yield rankings of perennial ryegrass (Lolium perenne L.) cultivars representing the range in phenotypes now available to New Zealand farmers as a result of recent breeding differed when those cultivars were grown in monocultures (as per standard protocols for cultivar yield trialling systems such as the National Forage Variety Trials) versus mixtures of grass and clover. This paper presents the rationale for the investigation by reviewing developments in perennial ryegrass breeding and evaluation in the context of grass–clover relationships in grazed pasture systems. The papers that follow report results from a multi-year, multi-site investigation comparing the yield, nutritive value and other productivity-related variables of eight perennial ryegrass cultivars grown with or without white clover (monoculture versus mixture respectively) at two levels of nitrogen fertiliser. Key considerations in the design of the experiment on which the investigation was based are discussed.


Rights statement

© 2017 The Royal Society of New Zealand


  • English

Does this contain Māori information or data?

  • No


Taylor & Francis Group

Journal title

New Zealand Journal of Agricultural Research




Chapman, D. M., Lee, J. M., Rossi, L., Cosgrove, G. P., Stevens, D. R., Crush, J. R., King, W. M., Edwards, G. R., & Popay, A. J. (2018). Implications of grass–clover interactions in dairy pastures for forage value indexing systems. 1. Context and rationale. New Zealand Journal of Agricultural Research, 6(2), 119–146. doi:10.1080/00288233.2017.1402353

Usage metrics


    Ref. manager