Agronomic program to improve the uniformity of broccoli for once-over mechanical harvest (VG06053)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Broccoli production can be an expensive, labour intensive exercise, with much of the Australian crop hand‐harvested. It would be far more cost effective for broccoli to be mechanically harvested. Matilda Fresh, the National Food Industry Strategy and Horticulture Australia have together invested in the first successful development of a commercial mechanical broccoli harvester. However, the highest percentage cut currently achievable by this mechanical harvester is 50 peer cent of the available heads.

In this project, AHR, Matilda Fresh, Sakata Seeds and South Pacific Seeds worked together to develop agronomic management strategies to improve the uniformity of the plant stand and, in turn, the efficiency of the mechanical harvester. The trials were run over three seasons in Gunalda, Qld, Toowoomba, Qld, Gatton, Qld and Armidale, NSW.

This project was able to improve the harvest percentage by up to 90 per cent, by ensuring a uniform plant stand. It was found that by increasing the plant density from 60,000 plants per hectare to 90,000 plants, the heads produced were taller with straigher stems, which made them well suited to mechanical harvesting. The varieties Gypsy and Atomic consisently produced tall straight stems with small heads when planted at a high density. It is important to note that the season (autumn or winter) and the district had a greater influence on yield than the individual variety. This result highlights the importance of growing a crop in the correct seasonal and geographic location for optimum yield and quality.

The trials also showed that planting with a single‐row planting gave a more uniform plant stand than a double‐row planting. As a result, a single‐row planting is recommended for mechanical harvesting of broccoli. It is also important to have uniform irrigation and nitrogen applications for a uniform plant stand. Variations in these two inputs across a planting will produce variability in plant height and reduce the efficiency of the mechanical harvester.