Harvest Best Practices
The macadamia harvest season is one of the most important periods of the year from both a production and quality perspective.
By the time the crop reaches maturity, most of the yield potential has already been determined through factors such as nutrition, pest and disease management, irrigation, canopy management and seasonal conditions. From this point on however, it is the harvesting and post-harvest handling operations that largely determine whether that quality is maintained – or lost.
Good harvesting practices are not simply about picking nuts up off the ground. They involve everything from orchard floor preparation and harvest timing through to dehusking, drying and storage management.
Pre-Harvest Preparation Matters
Good harvest efficiency begins before the first nuts are picked up. The aim of pre-harvest preparation is to remove or finely mulch:
- Old nuts
- Excess leaf litter
- Small sticks and branches
If this material is not managed properly it can reduce harvesting efficiency, increase machine wear and contribute to quality issues through excess foreign matter and poor nut recovery.
Timing is also important. If cleanup operations are carried out too early, immature nuts can contaminate the first harvest rounds. If left too late, mature crop can be lost during sweeping and mulching operations.
Harvest Timing Directly Influences Quality
One of the most common causes of quality decline is simply leaving nuts on the ground too long. Once nuts fall to the orchard floor they are immediately at risk of:
- Germination
- Mould
- Rodent damage
- Rancidity
For this reason, regular harvest intervals are extremely important. In many situations, it is more important to harvest the bulk of the crop quickly and consistently than to spend excessive time chasing the final small percentage of nuts during each round.
The ideal strategy is generally to keep the crop moving steadily through the system rather than allowing excessive build-up on the orchard floor.
Harvest Operations Efficiency is Important
Efficient harvest operations are not just about reducing labour and machinery costs. It also allows:
- Faster movement of crop into drying and storage after falling from the tree
- Greater recovery of grown crop
- Lower Unsound levels thereby maximising the farm gate $/kg price received
- Earlier completion of harvest (variety dependent)
- Reduced interference with flowering and next season management (variety dependent)
Long, drawn-out harvest seasons can create operational difficulties later in the year, particularly where harvest overlaps with flowering, early pest and disease control or canopy management operations. This is one reason why many growers now place a much greater focus on harvest efficiency and orchard logistics than they may have 15 or 20 years ago.
Dehusking, Drying and Storage are Critical
A good crop can still lose quality very quickly after harvest if handling systems are inadequate. Freshly harvested NIH (nut in husk) generates heat rapidly if left sitting in bins without adequate airflow. This can lead to reduced quality (and price received) through:
- Mould
- Internal discolouration
- Germination
- Rancidity
Ideally, freshly harvested nuts should be dehusked as quickly as practical (within 24 hours) after harvest.
Drying is equally important. High moisture content nuts that remain warm for extended periods are at high risk of quality decline, making controlled drying and airflow essential parts of maintaining kernel quality.
In practical terms, the best systems are generally those that:
- Keep the crop moving
- Avoid excessive storage times
- Maintain consistent airflow
- Avoid excessive drying temperatures
Harvest Management is About the Entire System
Good harvest outcomes are rarely achieved through one single operation. The best orchards generally combine:
- Good orchard floor preparation
- Timely harvest intervals
- Efficient machinery that is not aggressive
- Effective drying systems
- Good storage management
Ultimately, harvesting should be viewed as part of the overall orchard management system – not simply as the final operation of the season.
In many orchards, relatively small improvements in harvest management can produce significant benefits in:
- Total crop harvested
- Kernel quality
- Harvest efficiency
- Soil protection
- Long-term orchard performance
- ALL OF WHICH TRANSLATE TO IMPROVED RETURNS