Farmers are concerned about the short life of new perennial ryegrass pastures.  There are reports from some farmers on persistence failure within three years of pasture renewal, and we are now investigating the regional scale of the issue.

Poor persistence results in loss of perennial ryegrass plants, leading to invasion of weed species and reduced productivity.

There is no simple explanation for why this is happening.

Poor persistence is due to many overlapping causes, and some are outside our control.

Possible contributors are dry summers, hot summers, insect pests, grazing management, and soil damage (structure, pugging, compaction).  One factor on its own, does not necessarily result in the loss of ryegrass plants. But two or more in combination or even single challenges across consecutive years can result in plant loss.  An example is hot and dry weather conditions occurring at the same time as a major pest outbreak (e.g. black beetle or grass grub).

Failures of newly established pastures do occur even where choice of cultivar and endophyte, grazing management and soil fertility are well managed. In these situations, it is environment is the major driver in the failure of newly-sown ryegrass pastures to persist and we acknowledge that if your pasture management practices are well managed then the environment could be having a powerful effect.

What factors can we rule out?

There is no simple explanation for why this is happening; and it follows that there is no simple solution. Sometimes complex problems are only resolved by ruling out some of the factors that could be involved, and concentrating on those that remain. So, what can we rule out:

• Ryegrass seed sowing rate.
• New ryegrass cultivars.
• System type and stocking rate

See FVI and improved pasture performance page.

What can you do?

Keep good records on each paddock (grazings, residuals, fertiliser applications etc). One of the problems with trying to work out why a ryegrass paddock/s starts to decline is that we don’t know if there were any events that happened earlier that contributed e.g. overgrazing, pugging, an insect event.  Good paddock history can be valuable for the post-mortem.  We encourage farmers to capture this information wherever possible – but acknowledge this is easier said than done when there is a myriad of other data farmers are required to collect and report.

Consider if perennial ryegrass is the right option?  There are other options but these have their limitations and should be investigated for your situation.

Other options might be:

• annual crops,
• other perennial grass species e.g. tall fescue, cocksfoot
• perennial grazing species e.g. plantain
• shorter term pasture options e.g. stitching in Italian ryegrass.  

Lastly, acknowledge that if your practices are all in hand (being managed well) that the environment could be having a powerful effect, and this is largely beyond your control. Do not be too self-critical of your management skills – indeed there are many excellent pasture managers on farms in the northern North Island that still struggle to retain productive perennial ryegrass pastures.

 It appears that in some situations (by no means all the northern North Island) mother nature is making the environment too hostile for perennial ryegrass. In those situations, we do not currently have any perennial ryegrass technology and management packages that can prevent pasture decline. Hence, we may need to re-frame our expectations of ryegrass persistence, and accept that it is only a 3 or 4-year pasture, not a 10 or 12-year option.