Words by: Anne Lee
Plantain’s emergence from the Forages for Reduced Nitrate Leaching project as a “bit of a champion” may require a change in mindset from farmers looking to use it as a significant tool to limit nitrogen losses.
The way and extent to which farmers incorporate the plant into their forage systems would depend on the level of reductions they need, Agricom national product development manager Allister Moorhead told the Lincoln University Dairy Farm (LUDF) focus day at Ashley Dene last month.
“What we do know is that the consistency of its ability to reduce nitrate leaching is quite outstanding.”
It could be by including it in the seed mix during pasture renewal with plant populations topped up through direct drilling or broadcasting as needed through years four to 10 of the paddock’s life.
Plantain is not a perennial and without being topped up will decline from a level of 35-40% in the first season to 25-30% in the next, to 15-20% in the following season and then to 5-15%.
It’s also not a dominant species and the better ryegrass manager a farmer is the more difficulty they could have in maintaining plantain populations as the ryegrass out-competes the herb.
If greater reductions are required the paddock could go through that programme and then be sown in an Italian ryegrass/plantain mix that remained for two years before it was resown into permanent pasture that again contained plantain.
Research has shown that combining plantain with the more cool-season active Italian ryegrass can give huge reductions – up to 90% – in nitrate leaching.
That’s because of the effects of both plantain and the ability of the Italian ryegrass to take up more nitrogen due to its extending growing season.
For even greater reductions, particularly in non-irrigated areas farmers could follow the same rotation but add in two years of a pure plantain or plantain/white clover pasture after the Italian ryegrass/plantain.
“In some North Island areas it’s not uncommon to have 12% of the farm in chicory, for example, to give summer
protection. For them it might be as simple as a portion of that 12% going into a plantain crop which may last for two years.
When establishing plantain, it is important to remember it is a broadleaf herb and the number of herbicides able to be used to manage weeds over the establishment phase is extremely limited.
“But the significance of this species has a lot of people’s radars now and because of that the investment from chemical companies looking at alternative combinations and registration of them so you can functionally use them onfarm has dramatically lifted in the last two or three years.”
The FRNL programme was now looking at establishment methods using monitor farmers’ experiences as well as working with farmers on how they could use the herb over time.
Plantain’s low drymatter needs to be considered when allocating feed.
“One thing you have to do mentally is get your mind around what you’re leaving behind and what cows have consumed.”
Estimating covers on a drymatter per hectare basis had to be done with a different mindset than if scoring a ryegrass dominant paddock by eye
The level of research on plantain – including studies underway on Ashley Dene – should mean models such as Overseer can eventually take account of plantain levels onfarm so farmers are credited for nitrate leaching reductions.
