This first-year paddock of plantain/legume shows the pasture quality change possible on hill country
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Whangara Farms is looking at the potential of a plantain/legume mix to enhance the finishing capability of steep hill country. The operation lies 30km north of Gisborne and is a partnership between two Maori incorporations, covering 7,100ha and running 70,000 stock units. Whangara Farms general manager Richard Scholefield and scientist Tom Fraser tell us what the project has found to date.
What stage is the trial up to?
We're in our third year of three now. We planted 20ha in the first and second year and 19ha this year. That said, we are also planting Rohan – a spreading ryegrass – and clover mix. There was a lot of debate at field days about how the plantain/legume mix would compare to a grass, so we will run through that exercise as a comparison.
What mix have you settled upon?
13kg/ha – made up of 7-8kg of tonic plantain, 2-3kg of red clover and 2-3kg of white clover.
What is the sowing process?
We've found that putting the country through a summer crop first has led to a much better establishment of the plantain and legumes, because of the extra spray. Last year, we went in and sprayed out mid October, then grazed it hard, before flying on Hunter forage brassica and using stock to trample the seed in.
We have learned that you can't muck around with sowing date for the plantain. The paddock has to be sprayed out by mid March and the seed needs to be on by the end of March, before temperatures drop. We then put the sheep over the paddock again, to trample the seed in.
The helicopter pilot has developed a good technique for covering more of the paddock. Flying up into the hills works the seed into the sidelings. We've got a much better spread of seed compared to three years ago.
What's the cost/benefit analysis?
Development costs - including helicopter costs
Benefits at first lambing (set stocked with twin scanned ewes through until weaning)
|Weaning wgt kgs
When do you first graze the crop?
We treat the young crop with kid gloves. The plantain leaves are fine when it's young, so we let it get established and "robust" looking, before we graze it lightly with lambs. From there on, we treat it like new grass.
Do you use any urea?
Yes, a couple of small applications – 50kg/ha in spring and autumn. The plantain definitely responds well to it. We maintain our normal fertiliser program, which was a sulphur/super/potash mix this year.
Are the paddocks single blocks?
We have subdivided the 20ha paddocks into 4-5ha blocks with 5-wire electric fencing.
How's the plantain's longevity?
We are only in our third year, so early days. One of the big debates at our field days has been "what is considered success with this type of technique?" We believe that, if after four or five years there is 30-40 per cent of the paddock still in plantain and clover, then that is a success. You're not going to keep the grass out of these hill country blocks, so if you spray and end up with gaps, you'll just get weeds establishing. I think when the amount of plantain/clover drops below 20-30% we would look to go through the rotation again.
What stock are you running on the plantain?
Last year we lambed the triplet ewes on it, then finished lambs over summer. We got mixed results – because the dry limited everything – but were still well ahead of the control. This year, we'll put the twin-bearing ewes on it, then follow up with lamb finishing from late November. Note that the stocking rate is nearly double the control area.
Using the plantain/legume mix on hill country has to be a commercial reality for us to keep doing it. To be honest, we're sold on it and have the confidence to keep moving forward and carry on. We'll put 20ha in pasja this summer, then on into plantain/legume, but have the potential to sow up to 2000ha. The opportunity is pretty huge. We will probably focus on 800-1000ha of coastal land initially.
Robbie Love is unit manager on the block at Pakarae and has been doing a great job with the grazing management and is keen to continue improving his hill country.
We're also really pleased to have scientist Tom Fraser continue on with us after retiring from AgResearch. We appreciate the access to his expertise and others, and this has been a real bonus of being involved as a B+LNZ demonstration farm.
What have you learned, as this project has progressed?
You cannot cut corners. The main learning has been that timing is critical. We are on hill country that is been in "native" pastures for 100 years. There's a huge seed basket and tough mat there, which you've got to be able to break up. You can't just spray out and sow new species and expect magic results. You do need the break crop.
Spray, then sow a brassica, pasja – it doesn't matter – over summer. That break crop may be slow to establish and, come March, the farmer thinks "I can get another grazing out of that", so they delay spraying out. At Whangara, Richard has written in his diary "I am going to spray out the pasja crop" on a specific date. We're looking at a long-term pasture, not a short-term one. We've decided to spray out and have the plantain and legume seed in by late March.
How did you settle on the plantain/legume ratio?
The legume is really the main component. All hill country pastures in New Zealand are short in nitrogen. What we are trying to improve is the quality of pasture on this country. To do that, we have to get some nitrogen in the system. So we have to have a legume component in there. Thus, we've reduced the plantain percentage in the mix and increased the clover percentage.
Why not plant just the clovers?
Plantain on Whangara has been absolutely magic in winter and spring, but not so great in summer.
The plantain will not affect the amount of clover you ultimately end up with – and it gives you some cover in the early days. What it comes down to is that plantain establishes faster and fills the gaps – providing some cover from thistles.
What species of clover?
Use whatever works in your region.
What about the economics?
In the first spring, the increased stocking rate and lamb weight by weaning were sufficient to recover the costs of establishment in the first three months.
What is the realistic medium-term outlook for these paddocks?
When we are developing hill country through spraying and flying seed on, we need to rethink our expectations. We're not going to get the same change in pasture as we get through cultivated or sprayed and direct drilled planting.
So what percentage of introduced species do we need to get to make a difference? What we find is the nitrogen-fixing species improve all the pasture. By having a small component of high quality "new" species, there is better utilisation of the existing species. This results in more regrowth of these species, which are always higher quality than the old pastures.
This story was originally published in Heartland Sheep