Alan Kale1, Diana Mathers2, Dirk Wallace3
1 ELAK Consultants Ltd
2 DJ Communication
3 Foundation for Arable Research
kale.etal@xtra.co.nz
In February 2023, Cyclone Gabrielle caused catastrophic flooding across Hawke’s Bay, Wairoa, and Gisborne, inundating extensive areas of annual cropping land. The Foundation for Arable Research (FAR), in collaboration with MPI’s North Island Weather Event Fund, Vegetables Research & Innovation, and the Hawke’s Bay Regional Council, initiated a multi-year programme to document recovery processes, quantify soil and crop responses, and capture the lived experiences and lessons of affected growers.
What Was Done
The project followed 34 flood-affected sites across Central Hawke’s Bay, the Heretaunga Plains, and Wairoa over two cropping seasons. These sites represented a full range of arable and vegetable production systems including onions, maize, sweetcorn, peas, tomatoes, brassicas, and seed crops.
By 2024–25, Five onion case studies on the Heretaunga Plains tested productivity on previously inundated silt-mixed soils, while a maize trial at Eskdale evaluated compost amendments on a site where half the silt had been removed. In Wairoa where planting was not possible in the 2023-24 season, three farms with deep silt layers and two with mixed deposits demonstrated the challenges of extended remediation under limited access and resources.
In parallel, structured interviews captured farmer perspectives on soil recovery, business adaptation, and mental resilience. These included smaller single-operator enterprises and larger multi-crop businesses. Following on from this a Disaster Response Decisions framework was developed which summarised the two years of learnings and provided staged recommendations for “looking after yourself, your business, and your land.”
What Was Learned
Soils and crops recovered faster than expected.
By the second harvest after the cyclone, most silt-affected soils were described as “working better than before.” Where silty clays had been incorporated, residual clay lumps were visible but did not hinder productivity. Sites where sand dominated showed greater variability and required higher nutrient inputs, but production had largely normalised. In Wairoa, deeply buried soils (up to 700 mm silt) remained slow to recover and required repeated N, P and K applications plus organic matter rebuilding through grazing or green manure.
Crop yields across all crop types matched or exceeded pre-cyclone levels.
Onions – a high-risk, high-input crop – performed exceptionally well in year two, with yields of 70-86 t/ha considered average to above average. Dryland maize silage and grain crops produced comparable yields to pre-event seasons, and in some cases, higher. No additional pest or disease pressures emerged, confirming the resilience of these soils once physically re-worked and nutritionally balanced.
Silt removal was rarely beneficial.
Evidence from Eskdale showed no yield advantage from removing silt, and compost applications had no measurable effect. Removal created compaction risks and high costs, while working the silt in proved equally or more effective. Farmers concluded: “work with what you’ve got.”
Patience was essential.
Growers repeatedly emphasised the importance of waiting for soils to dry before cultivation. Those who delayed avoided machinery damage, compaction, and wasted effort. This lesson – “there was no disadvantage to taking time” – became a cornerstone of recovery advice.
Resilience was tested but strengthened.
Two years on, most growers reported that soils were “as good as before, or better,” but the mental and financial toll remained high. Smaller operators faced disproportionate strain, with some questioning the viability of continuing. Larger, diversified enterprises weathered the recovery more but became more risk-averse – avoiding high-value perennial plantings in flood-prone zones and reassessing asset protection and insurance. Across all businesses, community support and peer networks were cited as the most valuable form of help: “Take all the help that is offered.”
Institutional and regulatory pressures compounded stress.
Growers expressed frustration at overlapping demands – recovering land while facing changing water and land-use regulations. Many felt excluded from consultation processes and unsupported in representing their interests. These systemic pressures highlight the need for coordinated post-disaster governance that aligns recovery with long-term resilience planning.
What It Means
The collective findings challenge early pessimism about the agricultural viability of silt-affected land. Physical recovery of cropping soils was quicker and more complete than feared, provided that growers exercised patience, avoided unnecessary disturbance, and maintained organic matter and nutrient balance. The resilience of New Zealand’s alluvial cropping systems reflects both inherent soil properties and the practical ingenuity of growers responding to crisis.
However, financial resilience is far more fragile. The cyclone’s losses were largely absorbed within farm businesses, with limited external compensation. None of the interviewed growers believed they could withstand another comparable event in the near future. This underlines the urgency for integrated regional strategies that combine flood-risk mitigation, land-use planning, and mental-health support.
At a practical level, key recommendations emerging from this work include:
- Treat deposited silt as a resource, not waste – incorporate rather than remove.
- Delay cultivation until soils are trafficable
- Use quick-return crops to restore cash flow and confidence.
- Build soil organic matter through cover crops and grazing.
- Strengthen grower-to-grower networks as critical recovery infrastructure.