It’s the first study of its kind in New Zealand, as Back Track Dairies offers the chance to study the impacts of conventional and biological nutrient management on two separate units otherwise run under identical management.
The farms have similar cropping and fertiliser history and were converted to dairying only in 2012.
Farm owners Jeremy Casey and Kim Solly initially embarked on the study, with the blessing of equity partners Hank Murney Family Trust, so they could find out for themselves whether the biological approach could make a difference to soil, plant and ultimately animal health.
The 365ha farm is split into two units by a road, Back Track. In the conversion process the southern, 155ha farm became the biological unit while the northern 210ha farm was converted using conventional fertiliser management practice.
Shortly after the conversion began Jeremy discussed their programme with retired Lincoln University professor Tony Zwart and with his help and the support of Plant and Food, Lincoln University, DairyNZ and the South Island Dairying Development Centre a more scientifically robust protocol for the study was established.
A steering committee that includes representatives from each organisation as well two local farmers, Eddie Glass and John Wright, has been established to oversee the project.
Sustainable Farming Fund money is being sought and DairyNZ has indicated it will also support the study with funding providing the Sustainable Farming Fund application is successful. The outcome of the application will be known in March.
DairyNZ strategy and investment leader for productivity Dr Bruce Thorrold said DairyNZ would also want to be confident the protocol for the study was set so it could deliver on its aims and that reporting would be open and transparent.
He’s aware of the growing interest in new approaches to nutrient management and the keen desire of farmers to get more facts.
He’s happy for DairyNZ to go on a factfinding journey with farmers and will be looking to see the Canterbury study is as robust as the type of comparative study allows.
“If we see outcomes that we don’t expect then that will give us an incentive to roll out more research investment to work out what’s going on in these systems and help farmers capture the benefits fully,” he said.
Zwart too said his interest in the study stemmed from years of listening to proponents of conventional and biological approaches talking past each other and he was curious to get a better understanding of what was happening in the biological system.
“I want to see some science and actual measurements being made,” he said.
Ballance Agri-Nutrients is doing the fertiliser recommendations for the conventional farm while Don Hart from Healthy Soils is prescribing the applications for the biological farm based on Albrecht-Kinsey theories. The Albrecht approach to soil testing uses base saturation percentages to determine what nutrients are required with an emphasis on creating the correct balance of the cations calcium, magnesium, sodium and potassium.
The theory has drawn controversy over the years with some soil scientists disputing the accuracy of the tests used in determining what nutrients are needed.
But American Neal Kinsey, like a growing number of other biological advisors, stands by the theory and uses it to base his soil nutrient balancing advice.
In the 1990s he co-wrote a book, Hands on Agronomy, that re-defined the ideal ratio range for the cations in terms of base saturation percentage, using Albrecht’s theory and studies of others since him.
Kinsey is widely accepted as the modern day guru of the biological practice and in early November visited Back Track Dairies as part of a wider study tour to learn more about the Canterbury farm system trial.
To sharpen the focus of the study only more conventional fertiliser products with known nutrient levels such as ammonium sulphate, diammonium phosphate, dolomite, lime, serpentine super phosphate and lime will be used to balance the soil on the biological farm. Humates and compost or any other brews designed to build organic matter or promote microbial activity won’t be added in this study.
In that way it will be the Albrecht-Kinsey approach that’s being put under the spotlight.
Jeremy and Kim are openminded about the outcomes. They’re neither sceptics nor converts and have been hard working sharemilkers who went from wages to large-scale sharemilking with 1800 cows before achieving their dream of farm ownership through a significant share in an equity partnership in 2011. (Dairy Exporter, April 2011, pages 104-108)
Their interest in the biological system was piqued through Kim’s father, who owns Golden Bay Dolomite and has been running his farm using the biological approach.
“We wanted to test it though and see for ourselves what difference it could make – we want some robust answers,” Kim said.
The debate over different soil testing methods and recommendations can be complex and confusing with both sides claiming to back their arguments up with science, Jeremy said.
“I’m not a scientist, I’m a farmer. We just really wanted to know the truth. I want to see each system in action and over time see if there are differences in not just the soils but animal health issues as well.”
Profitability too is high up the list of priorities so economic data will be analysed closely. It’s a big commitment to put their farm’s productivity on the line in pursuit of answers but they’ve got the backing of a growing number of farmers, advisors and researchers all keen to see the outcomes. Monetary contributions have been made by individuals through pledge forms to help support the study and if backing from government and levy paying organisations is successful the depth and breadth of data collection as well as its robustness will be increased.
“We’ve decided we’ll go ahead with it even if we don’t get the funding now – there’s enough widespread interest in what we’re doing,” Jeremy said.
The steering committee, too, is committed to the project.
Key points
| Conventional | Biological | |
| Area | 210ha | 155ha |
| Cows | 748 | 552 |
| Stocking rate | 3.56 cows/ha | 3.56 cows/ha |
| Farm dairy | 54-bail automated | 54-bail automated |
| Supplement (kg DM/cow) | Up to 800 – 500 silage and 300 grain | Up to 800 – 500 silage and 300 grain |
| Production target 2013-14 | 1700 milksolids (MS)/ha | 1700 milksolids (MS)/ha |
What’s happening?
Three focus paddocks on each farm have been selected in the Back Track Dairies study based on similar soil nutrient levels as well as cropping and management history. They’ll form the basis for the study into the impacts of the biological approach on the soils and pastures.
Soil samples will be taken from these areas annually with samples from each farm sent to both Hills Laboratories and Perry Laboratories. Perry Laboratories will do the testing needed for the Albrecht-Kinsey approach.
Although each farm will undergo both testing regimes the conventional farm’s fertiliser recommendations will be based on Hills Laboratory results while the biological farm will use the Perry Laboratories analysis.
Plant and Food Research has carried out the initial soils analysis on physical and some chemical parameters and will continue to assess them each year. Plant and Food Research scientist Abie Horrox said the initial soils analysis done towards the end of 2013 gave a quasi baseline because the different treatments had already been instigated earlier. But it was still early enough in the study to provide good comparative information.
She said aggregate stability, carbon content, water holding capacity and biological population measurements including earthworm numbers have all been measured.
Monthly pasture composition assessments are also being made by Plant and Food Research although the collection of monthly pasture quality samples for parameters such as fibre, metabolisable energy and crude protein is to be done by an external provider. Fortnightly drymatter quantity measurements are also being taken.
Soil moisture monitoring will be done and as well as being used to schedule irrigation the data will be compared between the two systems.
Because the study design is a comparative farm system study rather than a fully replicated scientific trial the results won’t necessarily give a definitive winner in terms of the best system. It won’t necessarily explain why the results differ either.
“But it will add to the body of information available for farmers,” Horrox said.
The Back Track study has been set up so that, as much as possible, only the fertiliser approach will be different and other management factors will be the same on each farm. The cows have been randomly allocated to each unit in such a way that age structure, cow condition, lactation, Production and Breeding Worth are similar.
Stocking rate is the same although there’s an acknowledgement that it may differ between farms if pasture production differences become apparent.
Replacements will be returned to the farm they were born on when they enter the herd although youngstock will be reared off-farm together.
The two milking herds will be wintered together on conventionally managed areas but will return to their allocated farms. Each unit has its own 54-bail rotary farm dairy equipped with Milfos herd management automation that includes milk meters, automatic drafting and herd management software.
Data collected through that system and herd tests will provide information for milk production comparisons and other herd performance comparisons such as reproductive performance and somatic cell counts.
Profitability analysis and financial comparisons will be made between the two farms and with Lincoln University Dairy Farm.
How to follow the outcomes:
Dairy Exporter will be reporting extensively on the study. Focus days on Back Track Dairies will be included in Dairy Diary. Follow us on twitter @DairyExporterNZ and @Cantabannelee
In a nut shell
What is it? A three-year study comparing conventional fertiliser management with a biological approach.
Where? In Canterbury, two farms – one on each side of the road, same owners, same fertiliser and cropping history.
What’s being measured?
• Soil properties – physical and chemical.
• Plant composition, pasture quality and quantity.
• Milk production.
• Animal health and performance.
• Financials.
