The science trials in plots, animal stalls and on farms will test plants, mixes of plants and crops to reduce urinary nitrogen excretion. Crop sequences and plants that can capture more nitrogen in the soil to reduce nitrate leaching are also in the programme, DairyNZ senior scientist Dr Ina Pinxterhuis said.
“We need pasture species that combine high milk production and low nitrogen excretion in the urine and currently we are looking at which species and cultivars to include.”
DairyNZ estimates a payback of $2 billion a year if farmers can switch to forage and cropping systems that are effective and practical to use to reduce nitrogen leaching.
Pinxterhuis said the focus had to be beyond simple drymatter yield as a measure of forage crop or pasture grass effectiveness.
“We want forage that is more efficient for the animal to process. If it’s possible to feed drymatter with less nitrogen but the cow does more with it and there’s less excretion of nitrogen then we are all winning.”
Pinxterhuis was recruited by DairyNZ after heading similar farm system and environmental impact projects in the Netherlands. In this project she will use a new monitor farm network of 10 Canterbury farms to test forage changes.
Other farmers might be approached to participate in the programme in Waikato where DairyNZ’s Scott Farm and Lye Farm will run projects that include the analysis of the metabolic response of cows to diet changes.
“Those farmers can help us with what is practical and do-able. We can work through the perceived risks and learn what they need to be able to implement any changes.”
The programme team is comprised of soil, plant, animal and system scientists and modellers from DairyNZ, Foundation for Arable Research, AgResearch, Plant and Food Research, Landcare Research and Lincoln University. They have all committed cash or aligned core funding and Lincoln has made an in-kind contribution of its research facilities to the new project. The programme got the biggest chunk, of $21m spread over six years, from the Ministry of Business, Innovation and Employment’s (MBIE) biological industries research fund when allocations were announced six months ago.
Pinxterhuis said it was similar to but separate from the cross-agency Pastoral 21 programme that has MBIE, DairyNZ, Fonterra, Dairy Companies Association NZ, and Beef + Lamb NZ as co-investors.
It’s studying the environmental impact of high and low stocking rate systems and changes to winter management.
Rather than looking at stock management changes, the new programme is investigating more in-depth how different crop species and grazing systems can make better use of nitrogen.
“We have seen this with diverse pastures; it could be just because there’s a lower nitrogen concentration in that feed but we need to verify that difference to be able to give clear advice.”
“The focus is on our grazing systems and having cows on crop and pasture but still mitigating their nitrogen loss. We don’t want a solution that creates more problems on the farm.”
Winter-active crops that can absorb nutrients will also be grown.
“Some crops hold more water and dilute the nitrogen from animals so how we typify those species and their effect is also to be considered, as is the nitrogen uptake of plants at the edge of a urine patch rather than solely in the contained area measured by a lysimeter.”
The programme is split into three research sections; the first being to test candidate pasture options to discover how they decrease urinary nitrogen output, increase nitrogen uptake and affect urine patch dynamics.
The second section is to define the chemical, nutritional and agronomic attributes required in forage crops and construct crop sequences with supporting soil management practices. The third section involves using simulation models, farm systems experiments, on-farm research, and co-development with endusers to accelerate farmer uptake.
