A test for alternatives

The science or at least explanations over why a particular approach works or doesn’t can all sound plausible.
In mid-Canterbury, dairy farmers Jeremy Casey and Kim Solly, together with their equity partners the Murney Family Trust, are bravely putting the two dairy units in their Back Track Dairies business under the spotlight, running one under a conventional fertiliser approach and the other under an alternative nutrient management system.
Soil fertility on the conventional unit, Waiora, is managed by Ballance Agri-Nutrients while the alternative approach is based on the Albrecht-Kinsey theory.
It focuses on establishing a particular balance of soil nutrients, particularly the cations calcium, magnesium, potassium and sodium with the emphasis on feeding the soil rather than applying nutrients to directly feed plants.
Soil recommendations on the alternatively run unit, Whakapono, are being made by biological farming and soil fertility consultant Don Hart from Top Soils.
Jeremy and Kim decided four years ago to run the units under the different approaches because, while they were interested in the alternative methods, they needed convincing with objective data.
“The only way we thought we’d ever really know was if we ran both and made the comparison,” Jeremy says.
Others have been interested too and two seasons ago – thanks to funding from farmers and others and their own investment – they were able to start collecting data to compare each unit.
The study become more robust with the establishment of a steering committee, headed by Lincoln University Emeritus Professor Tony Zwart.
Soil quality parameters, soil fertility levels, pasture information, milk production and other animal information including animal health and reproductive performance were collected using experts from Lincoln University and Plant and Food as well as the soil fertility companies and Jeremy through his own farm statistics.
This season, thanks to a funding commitment of $30,000 each year for three years from DairyNZ as well as $23,000 funding from AgMardt, data collection and analysis over a three-year period is assured.
The project is being managed by the Agribusiness and Economics Research Unit at Lincoln University and senior researcher Glen Greer.
Weekly farm summaries and other information is now available on the South Island Dairy Development Centre website – www.siddc.org.nz under the research tab.
Tony says being able to compare the two dairy units directly with the Lincoln University Dairy Farm (LUDF) and give farmers weekly information on the same basis as LUDF adds further value to the study.
He admits the level of funding is a little constraining on the amount of information that can be gathered and the frequency samples can be taken but it will still give farmers comprehensive comparative results.
Apart from the soil fertility management differences Jeremy runs the two pivot-irrigated units in the same way.
Each unit is separated by a road with the smaller, 155 effective ha, Whakapono peak milking 510 cows this season and the conventional 210 effective ha Waiora milking 690 cows both at a stocking rate of 3.3cows/ha.
Close to 800kg drymatter per cow of supplement is budgeted to be fed this season as grain and palm kernel in the farm dairy and as pit silage and balage fed in the paddock.
Jeremy and Kim have purposely reduced nitrogen applications on both units to ensure they’re not inhibiting clover production and to see if clover can replace the bagged input.
This season they’ll apply 150kg of nitrogen per ha on Waiora and 100kg N/ha on Whakapono.  
Soils are tested on both dairy units providing both a conventional soils test result and a test result used by Albrecht-Kinsey proponents focusing on base saturation levels, the Resin P test for phosphorus and trace elements.
Both the Ballance advisor and Don see both sets of test results for both dairy units.
The products then recommended by both are largely conventional fertilisers although the alternative unit has received phosphorous in the form of guano in the past as well as dolomite and trace elements boron, copper, cobalt and zinc.
Last year the total fertiliser spend on the alternative unit was $871/ha while on the conventional unit it was $731/ha.
No other soil additives are used such as humates or composts as the study is seeking to first assess the Albrecht-Kinsey approach and it’s important all the inputs have stringently measured nutrient levels and results aren’t influenced by other organic properties.
Back in 2013 the cows were assigned to each unit to give a fair balance in terms of age structure, breeding worth, animal health history, calving date and production.
They’re wintered together but at each calving return to their assigned units.  
This is the fourth season Jeremy and Kim have run each unit under the two soil fertility approaches and the hope is with another two season’s worth of data to come, any differences that might show up will have had enough time to do so.
Three paddocks with similar histories on each farm were identified by researchers back in 2013 with measures taken to give a baseline level.
Since then the same paddocks have been sampled regularly for both soil and pasture parameters.
To date there have been few stand out differences in the parameters being measured.
At a mid-season review all the experts said it was too soon to put any differences they do see down to the variation in the nutrient management approach.
Some parameters have gone up one year only to go down again the next and vice versa.
But Plant and Food research scientist Richard Gillespie said they were watching to see if a trend could be emerging when it comes to earthworm numbers, readily available sulphur and soil magnesium, with each higher on Whakapono.
The differences in soil nutrient levels might be explained by the fertiliser history of each with Whakapono receiving more sulphur and magnesium-based fertilisers over the study period to date, although it was noted serpentine super has been used on the conventional farm and it contains magnesium as well as sulphur and phosphorus.
Three times as many earthworms a square metre showed on both units in the second year of sampling but then numbers had declined slightly at the time of sampling on both this season.
Numbers on the alternative unit, Whakapono, have been consistently greater than on the conventional unit with the difference increasing from 110 earthworms/m2 in 2013 to 372 in 2015.
It’s also been noted one of the three paddocks on Whakapono has always had inherently more clover than the others and might be making interpretation of clover density results more difficult.
Dr Racheal Bryant of Lincoln University reported while it was too early to draw any conclusions, tiller density on the conventional farm had tended to be higher than the alternative unit and clover density had tended to be higher on the alternative unit compared with Waiora, the conventional farm.
A similar trend was apparent when it came to pasture composition with Waiora samples suggesting a slightly greater percentage of ryegrass and the opposite for clover.
Crude protein levels in the three samples taken so far this season showed a declining trend for the conventional unit while levels had remained steadier on the alternative unit.
Metabolisable energy levels were similar across all three sample periods with no distinguishable difference between both units.
In terms of production and animal health both units were running neck and neck, Jeremy said.
Cow condition is assessed by an independent assessor Brenda Lynch with each unit showing similar trends.
Mastitis, lame cows and somatic cell counts were also close although for each parameter the conventional unit was slightly higher in number.
In the second week of December cows were still producing 2.14kg MS/cow with grain increased in the farm dairy to combat a decline in feed quality and irrigation deficit due to a breakdown with the irrigation scheme.
This season Jeremy Savage from Macfarlane Rural Business is running both units’ financials and physical data through the Dairy Systems Monitoring benchmarking system so the performance of each can be compared with about 120 other farms.
Budgets and cashflows were updated regularly through the season based on actuals in terms of both income and expenditure.
He’s also used Farmax modelling to compare both units and found very little difference between each to date.
A major field day will be held on the property on May 10 to review the season and results.