These pages summarise the current knowledge on this topic and has been agreed by the Pasture Renewal Leadership Group. This Pasture Renewal Group is a DairyNZ-led industry group that includes researchers, the seed industry, farmers and agricultural contractors, and was formed to develop better tools, resources and advice for farmers.
It has been suggested low sowing rates may improve ryegrass persistence. DairyNZ is testing this theory in plot trials.
Pro’s and con’s – standard vs low perennial ryegrass sowing rates
Good conditions a must for low sowing rate
If low ryegrass sowing rates are to be successful, you must have excellent conditions for the new pasture to establish. This includes producing a good seedbed (fine, firm, consolidated). As well as conserving moisture, this allows seed to be sown at the right depth.
Control flatweeds with herbicide(s) in the first 6 weeks after sowing, regardless of ryegrass sowing rate.
Standard rate increases yield
Using a higher ryegrass sowing rates usually gives a temporary (not long term) increase in DM yield over the first 1-3 grazings. This varies, but might be an extra 500kg DM/ha, with a value of $150-200/ha (using 30-40c/kg DM for this high quality late autumn/winter feed). Cost of an extra 6kg/ha seed may be $60-90/ha.
Lower rate increases clover
Lower ryegrass sowing rates generally gives higher clover content in the pasture, which in turn improves the feed quality and the animal performance.
Lower rate increases weeds
Lower ryegrass sowing rates also generally means more weeds in a pasture. If weeds are a problem (particularly grass weeds such as browntop, poa etc.) we recommend using standard sowing rates and taking into account sowing method (see below).
Sowing method affects sowing rate, as the diagram below shows. Where weeds are a problem we recommend method jbelow.
Summary - standard vs low perennial ryegrass sowing rates