Performance of new dairy pastures

Abstract

It is common practice to renew old and "run-out" pastures that are not performing. Renewing pasture is costly so it is critical that the regrassing pays off. This trial on ten irrigated dairy farms from North Canterbury to North Otago was initiated to determine the value of regrassing on long term production and persistence of the new pastures. A pasture, deemed as run-out by the farmer, was subdivided and one half was renewed to a novel endophyte ryegrass pasture while the remainder of the paddock remained in the old pasture. The new pasture was compared with the original and another pasture on the same farm, considered by the farmer to be high performing. Pasture composition, production, and quality and pasture pests and endophyte infection have been monitored for two years. Herbage production is presented for the first 2 years of an ongoing trial, with quality and determination of wild/novel endophyte. When averaged across all 10 farms, the "control", "new" and "good" paddocks have all produced 15 t DM/ha in the year to May 2012. Levels of novel endophyte have remained high in the majority of new paddocks over the first 2 years. Clover root weevil is now present on all ten farms, at high levels (>200/m2) in some paddocks. Production from the new pastures equalled the total DM production from old pastures within 10 months of sowing. However, 2 years following pasture renewal, there has been no production advantage achieved from regrassing a stable old pasture. Keywords: pasture renewal, pasture persistence, irrigated dairy pastures, endophyte, pasture production, pasture composition

Pasture renewal on Bay of Plenty and Waikato dairy farms: impacts on pasture production and invertebrate populations post-establishment

“…Results from this trial are inconsistent with results from irrigated dairy farms in Canterbury and North Otago, where there was no difference between renewed and unrenewed pastures in DM production (Taylor et al 2012). Two key reasons for the difference between findings of Taylor et al (2012) and those presented here are that firstly, the Waikato/BoP study did not incorporate DM production during the establishment year (which may be much less in the renewed than unrenewed pastures), and secondly, the lack of irrigation in Waikato and BoP pastures. The summer/autumn drought frequently experienced in these northern regions, coupled with high black beetle and other pest populations, contributes to sown species mortality, weed ingress and loss of DM production.…”

Stability and purity of selected ryegrass Epichloë endophytes in New Zealand dairy pastures

“…For the seven pastures where contamination was detected, predicted mean contamination was typically ≤7%, except for one pasture, which averaged 20% of total tillers tested. In this case, the contaminating endophyte was predominantly AR1 (16 out of 18 tillers), in a pasture that was known to have only partial herbicide kill during the pasture renewal process (Taylor et al, 2012).…”

“…Four pastures had less than 70% infection, the most notable being the Te Teko North Island pasture at 41%. The cause of the <70% infection in one of these South Island pastures is likely a result of the pasture renewal process failing to kill all the endophyte‐free plants from the old pasture as no chemical control was used on this organic farm (Taylor et al, 2012).…”

“…The ryegrass ( L. perenne ) pastures sampled in the South Island from the renewal–persistence project were from irrigated areas of the eastern coastal region, extending from North Canterbury to North Otago (42.8°–45.0° S) (Taylor et al, 2012). Ten pastures, each from a different farm, were sown in either autumn ( n = 8) or spring ( n = 2) of 2010.…”

“…To address this knowledge gap, in this study, we utilized dairy pastures in the North Island and South Island, most of which were part of a project investigating the value of pasture renewal and drivers of pasture persistence. Full details of the renewal–persistence project, along with the initial endophyte results, have been described by Rennie et al (2011), Taylor et al (2012), and Tozer et al (2015). Here, we report on the change over time in the percentage of tillers infected with endophyte and the endophyte strain in ryegrass sampled for up to 7 years from newly (<1 year) or recently (2–6 years old) renovated pastures.…”