Farmers inspect a field of 100 per cent plantain to be strip fed in three weeks.
Over 100 Tararua farmers attended a Dairy NZ-organised field day at Te Rehunga on Neil Filer's property to learn about progress in growing plantain as a pasture crop.
This was partly to outline the progress so far of the Tararua Plantain Project which has had 19 farmers trialling plantain throughout Tararua in the first of a three-year trial.
There are 129 more interested in the results.
Motivation to trial plantain has come from the discovery that apart from it being a good forage crop it has had a huge impact on reducing nitrogen leaching of soils.
Given the strict rules now imposed on dairy farmers over nitrogen leaching this is seen by Dairy NZ as one of a number of ways to reduce nitrogen being released into pastures and ultimately the rivers.
After a welcome by Mavis Mullins scientist Glen Jackson explained the different ways plantain can reduce nitrogen based on a wide range of research sources:
• Plantain reduces the concentration of nitrogen in a cow's urine by 30 per cent in peak growth season and 50 per cent in autumn.
• On plantain a cow's rumen holds more under-graded protein meaning less nitrogen is released.
• Plantain, being a wetter crop, causes the cows to urinate a lot more, diluting the nitrogen content.
• Plantain provides a biological inhibitor which reduces the conversion of ammonia in the soil to nitrate.
• Some evidence is suggesting plantain reduces the production of nitrous oxide – a greenhouse gas.
Mike Dodd, scientist with AgResearch then reported on tests from the local farms which showed there was little difference in the production of dry matter compared with ryegrass and clover. He predicted plantain production over a few years would decline as weeds invaded and would need to be replaced but discussion among farmers from both Tararua and from around NZ was inconclusive as to whether pastures could self-seed effectively or need to be sprayed, ploughed and drilled.
Neil Filer explained his first year's operation, planting seven paddocks in 100 per cent plantain and mixing plantain in with ryegrass and clover in a mix in others. He has strip grazed and cut the crops and is still experimenting with best practice.
Debate followed over how dairy farmers growing plantain could get recognition from the Ministry through Overseer the mechanism it uses to measure nitrogen leaching.
Dairy NZ Spokesman Adam Dukur said the Ministry has agreed to include growth of plantain as a credit to dairy farmers by May 2020 and a method to assess how much plantain there is in a mixed pasture was being worked out.
Farmers then inspected the plantain crops before having lunch.