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On Farm Story
FARMERS WEEKLY – farmersweekly.co.nz – March 7, 2022
Diversity for sustainability Concern for the soil structure after summer maize cropping with conventional tillage has led Northland dairy farmers Adam and Laura Cullen to introduce multi-species cover crops over the prior winter and use direct drilling where possible. They are only beginning to see the benefits of this regenerative approach, they told Hugh Stringleman. ADAM Cullen, of Ararua in the Kaipara District, has rediscovered his enthusiasm for agriculture and applies his curiosity to finding new ways of dairying better, says his wife Laura. The change of mindset prioritises improving the environment and the farm resources rather than constantly driving for production. But the Cullens are not following a formula or prescription, rather being adaptive to their circumstances and farming conditions. The young couple with two small boys, Hugh and Gilbert, have a 450-cow split-calving herd on the 200ha effective predominantly Waiotira clay loam
soil, previously the family farm of parents Bill and the late Gael Cullen. One of five children, Adam was born and brought up on a drystock farm near Paparoa before going to University of Waikato to study for a diploma of forestry management, followed by a science degree in resource and environment planning. He met marketing and communications specialist Laura in Hamilton and after some overseas experience Adam spent two and a half years as a Ravensdown fertiliser representative learning the fundamentals of nutrient management.
COMPARISON: Adam is keen on visual soil assessments, showing the change in soil health under cover crop.
In late 2008 they moved back to Ararua for Adam to farm manage then sharemilk for Bill and Gael, while Laura continued to work in Auckland. The farm was reconverted to dairying, with a 50-bale rotary, cup removal, teat spraying, effluent system, roading and paddock subdivision and Adam began what he now calls his conventional drive for more milk. After growing the herd size to 550 cows in 2014, half-andhalf autumn and spring calving, with a winter milk contract for Fonterra, and annual production of 175,000kg milksolids, Adam was working continually through the year. “It was my ambition to get to 1000kg/ha, with what was probably System 3 with conserved fodder, but that was never achieved,” Adam said. “The peak of 950kg has now come back to 750kg, with fewer cows and a more sustainable pace. “That 150,000kg production feels more consistent in good and bad years rather than chasing the occasional great season. “My success is no longer defined by milk production, but gaining knowledge for genuinely improving what we have here,” he said. The fine clay soil structure and its compaction by the maize cropping and pasture re-establishment was always a concern for Adam and he looked for ways of mitigation. Ararua can get very wet in winter, when pugging is a big
POSITIVITY: Adam and Laura Cullen have a newfound enthusiasm for dairying in Northland when multi-species cover cropping has become the first stage of maize growing.
risk, and very dry and solid in the summer. Despite using different ryegrass varieties and some alternative species, dry matter eaten by the cows was slowly declining, which Adam put down to poorer soil health. “Tighter soil structure not allowing root growth and aeration. Hard and discoloured soil that took months and many inputs to recover,” he said. “We lost pasture growth rates in the shoulders of the season and we were slow to get started again after rain.”
Purchase of the farm five years back came after a period of even longer hours for Adam and a degree of disillusionment and being burnt out. Laura suggested he attend a three-day soil management workshop led by Nicole Masters, director of Integrity Soils. “I went along with an open mind and I found the messages clear and easy to understand,” he said. “I was re-energised by the possibilities and motivated to shift from cultivation to using cover crops to feed and aerate the soil before maize sowing.” Cropping and regrassing has been a way of maintaining ryegrass and clover pastures and keeping kikuyu inundation at bay. Up to 20ha of summer maize is grown each year and now 10ha is still established with conventional cultivation and the other 10ha direct drilled after a cover crop during the winter. Multi-species cover crops for grazing and/or baleage establish diverse and deeper root systems and feed the soil biota, including worms, before allowing the conditions for direct drilling of maize.
I was re-energised by the possibilities and motivated to shift from cultivation to using cover crops to feed and aerate the soil before maize sowing. Adam Culllen FILLING OUT: Adam in a paddock of summer maize he sowed with a tyne drill after a cover crop when the local direct drill wasn’t available.
