Dirk Wallace1, Alan Kale2, Diana Mathers3, Elliot Calendar4, Melanie Briant4
1 Senior Researcher, FAR, 2 ELAK Consultants Ltd, 3 DJ Communications, 4 EC Consulting Ltd
dirk.wallace@far.org.nz
The Foundation for Arable Research (FAR) funded by MPI and Vegetable Research & Innovation, initiated a project in September 2023 to document and capture growers’ recovery experiences from Cyclone Gabrielle, offering insights for future adverse events.
What Was Done:
The project established 46 case study sites across 9 clusters in Hawke’s Bay and Gisborne/Tolaga Bay, encompassing diverse locations, crop types, and grower approaches. Sites included varying damage scenarios: silt removed, retained, or undisturbed, and the use or absence of cover crops. Growers implemented a range of recovery strategies:
What Was Learned:
Regional Weather Impact: Recovery success was influenced by post-cyclone weather. Central Hawke’s Bay and Heretaunga Plains benefited from favourable growing conditions, leading to successful cropping and normal-to-above-average yields. Conversely, Wairoa, Gisborne, and Tolaga Bay experienced continual rain, hampering access, causing poor growth, increased leaf disease, and challenging harvests.
Sediment Type Significance: The nature of deposited sediment critically influenced outcomes. Silty clay loams generally enabled successful cropping and a return to normal rotations. However, sandy sediments resulted in poorer crops and increased financial risks due to issues like reduced moisture retention. Deep silt layers often restricted root access and nutrient uptake.
Cultivation and Timing Insights:
Silt’s moisture-retaining properties necessitated longer drying periods and more cultivation passes. Extra deep ripping was commonly required to address floodwater-induced compaction. Ploughing proved effective for aeration. Timely cultivation after sufficient drying reduced the number of passes needed.
Crop-Specific Challenges: While Hawke’s Bay saw no increased pest/disease inputs, Gisborne/Tolaga faced Northern Leaf Blight in maize and new weed issues like sedge grass. Volunteer maize was a significant problem, requiring strategic management like false seedbeds. Late planting often led to reduced yields.
Grower Resilience:
Growers’ existing knowledge, experience, and strong informal networks were vital for successful recovery. The importance of self-care and seeking external assistance was also highlighted.
What It Means: For many, particularly with silty clay loams and favourable weather, a rapid return to productive cropping with normal yields is achievable through intensive, adaptive management. However, areas with sandy deposits or persistent wetness face greater, longer-term challenges and financial risks.