Automation harvesting of whole-head iceberg lettuce.

The horticulture sector is heavily reliant on access to seasonal labour for many field operations, including harvest. Movement restrictions because of Covid-19, post-Brexit uncertainty, competition from other sectors, and the lack of suitable UK-based labour have driven growers to seek investments in labour-replacing technologies.

99,000 tonnes of lettuce were harvested by seasonal workers in the UK in 2019 with a farm gate value of £178 million (Defra BHS, 2020), UK's highest value field vegetable crop.

This project has identified an opportunity to automate the process, and reduce the reliance on seasonal labour, by developing an innovative robotic solution.

* We intend to adapt existing mechanical capability and lift the lettuce clear of the ground by discs and then gripping the stem with pinch belts.

* The lettuce will then be presented to camera sensors that will direct an air blast which will blow the outer wrapper leaves of the lettuce head clear to expose the stem.
* Machine vision via deep segmentation will then be deployed using a second camera sensor to train a deep learning model to identify the precise location to be cut.

The three separate developments will be combined to form a prototype for field trials towards the end of the 2021 UK season.

Engagement with end-users has confirmed their need and willingness to be part of the development of such a machine. Early indications are that harvesting costs could be reduced by around £5,000 per hectare per annum.

123,000ha of lettuce and chicory was grown in the EU in 2018 (FaoStat, 2020) with similar areas in the USA. These areas have similar issues to the UK with access to seasonal labour, therefore the potential market for such an innovative machine is extensive.