The FRNL principles applied are:
- Reduce nitrogen in cow diets, through growing and feeding plantain and fodder beet on the milking platform and support blocks
- Capture nitrogen during risk periods with catch crops and plantain
Some other strategies also applied were to
- Use lower-N imported supplements e.g. lifted fodder beet and maize silage
- Reduce N fertiliser
- Reduce stocking rate in accordance with reduced inputs
The expandable sections below cover experiences of our monitor farmers.
Fodder beet is used as a home-grown, low-N feed to fill the autumn and winter feed gap, reducing the amount of N passing through the cow. Farmers considered:
- Paddock selection – where possible the lowest performing paddocks were selected to maximise the return of the cost of cropping. Back to back growing of the same crop is not recommended due to increased pest, disease and weed risk.
- Opening the crop faces to allow easy access – lifting fodder beet to create a headland, lifted fodder beet was fed on pasture or feed-pad.
- Acidosis – farmers used a transition plan with the goals of feeding between 4 and 7 kg/DM of fodder beet at dry off. Several also used supplements containing magnesium oxide to reduce the risk of acidosis.
- Getting the area in crop right – too many paddocks in crop can create a feed pinch the following spring, with too many paddocks out of rotation.
- Regrassing – two farms noted that fat-hen was a problem when re-sowing pasture after a crop. This disappeared again during the season, notably after being mowed.
- Back to back cropping – two farms noted that fathen was a problem in the second year of back to back cropping of fodder beet; back to back growing of the same crop is not recommended due to increased pest, disease and weed risk.
- Low-N crops other than fodder beet also provide opportunities. E.g. growing maize and grazing it in situ has been an interesting innovation on Highlands farm. It is a low N forage crop consumed in late summer and early autumn and can be followed with Italian ryegrass or other crops. Leaching from a grazed maize crop cannot be estimated yet with Overseer.
Plantain is used to dilute urine, increase plant N uptake from soil and reduce nitrification rate in the soil. A variety of approaches were used to establish and graze plantain and to manage weeds. The farmers considered this:
- Spraying out paddocks and direct drilling a mixed pasture including plantain in spring/early summer was the most successful approach to establish plantain on farm.
- Introducing plantain in existing pastures was harder and when starting from no plantain, the resulting plantain content was not significant. However, when broadcasting, costs can be as low as seed cost only, so repeated sowings are possible and may result in sufficient (>30%) plantain content.
- Introducing plantain in existing pastures was harder and did not result in high enough plantain content. However, costs can be as low as seed cost only, so repeated sowings are possible.
- In the Canterbury region, February was too late to try and establish plantain into existing pastures.
- Weed control in newly established pasture with plantain was an issue, as many sprays used will also kill plantain. The solutions considered were to spot spray, use a catch crop after fodder beet before sowing mixed pasture, and direct drill plantain in existing pasture.
- Although promising in a research setting, plantain did not persist under current sheep and beef grazing management. Diverse pastures rapidly transformed to a major proportion of grass. Therefore, plantain in pasture could not be expected to decrease nitrate leaching over several years.
- Plantain might be useful to reduce nitrate leaching from paddocks grazed in autumn, if they were established with a large proportion of plantain and managed as a late summer-autumn forage crop like rape, but it was not possible to experimentally test this.
Catch crops are grown for a variety of reasons on the farms, mainly to reduce N leaching, increase yields and to control weeds. The farmers thought the below should be considered:
- Selection of species – choose a species or combination of species that will fit with climate, main winter crop, and farm system.
- Establishment of the crop – wet weather and soil type can delay establishment, especially following fodder beet where cultivation might be required. However, even then economically useful yields of the catch crops for making silage were evident in the field.
- Harvesting vs grazing – wet weather can delay harvesting and regrassing. Options considered were to spray out and graze rather than harvest.
- Reducing nitrate leaching on sheep and beef farms – catch crops following the forage crops emerged as the method with the greatest potential.
For a full report on the catch crop results of the Canterbury dairy monitor farms, click here.
Monitor farmer biographies
Follow the progress of the monitor farmers to help aid your own decisions to reduce nitrate leaching. Click on each farm below for more information.
The geographic spread of the monitor farms and range of systems represented means every farmer in Canterbury should have a farm they can identify with.
Grant and Jan Early
Grant and Jan Early are dairy farm owners from Mayfield.
Eric and Maxine Watson
Eric and Maxine are arable farmers from Wakanui.
Chris, Nigel and Ross Rathgen
The Rathgen family run a mixed dairy and arable farm system in St Andrews.
Brent and Maryn Austin
Brent and Maryn are arable farmers from Mayfield.
Peter and Joc Kinney
Peter and Joc Kinney are dairy farmers from Culverden.
Tony Coltman dairy farms near Dunsandel.
Bill and Shirley Wright
Bill and Shirley Wright are sheep and beef farm owners from Cave.
Blair and Amie Kirkland
Blair and Amie Kirkland are sheep and beef farmer owners from Parnassus.
Paritea, Ngāi Tahu
Sam Lovelock managed Paritea, a dairy farm of Ngāi Tahu Farming at Whenua Hoe, Eyrewell.
Parekarangi Trust farm
Parekarangi Trust farm, Rotorua, became a monitor farm in 2016.