Botanical survey of perennial ryegrass-based dairy pastures in three regions of New Zealand: implications for ryegrass persistence

• Published in: New Zealand journal of agricultural research Vol. 57; no. 1; pp. 14 - 29
• Main Authors: Tozer, KN, Chapman, DF, Bell, NL, Crush, JR, King, WM, Rennie, GM, Wilson, DJ, Mapp, NR, Rossi, L, Aalders, LT, Cameron, CA
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.01.2014; Taylor & Francis Ltd
• Subjects: autumn; botanical composition; broadleaf weeds; buried seeds; Costelytra zealandica; Dairy farms; dairy pastures; diploidy; Evaluation; Grasses; Lolium perenne; Nematoda; pasture persistence; pasture pests; Pastures; ploidy; Ryegrasses; soil; sown pastures; surveys; tetraploidy; Turfgrasses; weed ingress; winter; New Zealand
• ISSN: 1175-8775; 0028-8233; 1175-8775
• DOI: 10.1080/00288233.2013.863785

A botanical survey of 24 commercial dairy pastures ranging in post-sowing age and perennial ryegrass type (mid-season diploid, late-season diploid, tetraploid) was undertaken in each of Waikato-Bay of Plenty (BoP), Taranaki and Canterbury during autumn/winter. The mean perennial ryegrass proportion (85% of total DM) and tiller density (3252 m ⁻²) was greatest in Canterbury and the broadleaved weed proportion lowest (2%). Conversely, Waikato–BoP had the lowest ryegrass proportion (59%), tiller density (1817 m ⁻²) and greatest proportion of broadleaved weeds (15%), with Taranaki intermediate. Tiller density was greater in pastures sown with diploid rather than tetraploids (averaging 3033 vs. 1784 m ⁻²). Grass grub (Costelytra zealandica , 11 m ⁻²) populations were lowest in the youngest age category pastures where nematode populations were highest (80 g ⁻¹ dry soil). The soil seedbank was dominated by unsown species (with total species emergence averaging 4594 seeds m ⁻²), with negligible ryegrass emergence.