Demonstration Site Summary: Cover crops in avocado orchard

Overview

Karlee Bertola runs King River Avocados – a mixed orchard enterprise integrating avocado production with pasture-based grazing. The business is actively transitioning to regenerative orchard management, focusing on soil health, diverse groundcover establishment, biological activity, and improved tree performance across inter-row systems.

The demonstration involves establishing diverse orchard inter-row cover crops, and under-row cover crops whilst measuring soil health, microbial activity, pasture quality, compaction, species diversity, and avocado tree response. A key focus is understanding whether diverse cover crops can self-regenerate and reduce long-term sowing requirements in an organic system.

Early cover crops that were established prior to funding (2023) were allowed to go to seed in some areas, which regenerated naturally in Summer 2024. New areas of warm season cover crops were planted and solarisation via weed matting was implemented in Summer 2024. Cool season cover crops were sown in Autumn 2025 and were established that Spring. Soil and sap testing was undertaken for baseline data and will be done again in 2026.

Cover crops have been slashed after seeding to provide mulch, and grazing geese have utilised the diverse forage effectively.

Key findings so far…

• Early cover crop areas from 2023 have successfully self-regenerated, with oats, crimson clover, vetch, radish and brassica re-establishing without re-sowing, showing promising potential for long-term reduction in seed inputs.
• New areas sown in early spring 2024 are thriving, with visible improvements in tree health. Photos show sequential sowing blocks at different maturity stages, with avocado trees displaying robust reddish new growth, indicating strong nutrient uptake.
• The orchard has been managed entirely organically. Weed matting was used to solarise ground before sowing without herbicides and has proven effective. Notably, kikuyu previously dominating inter-rows has not returned in any sown areas.

See more:

• ‘Cover Crop Field Day’ video