Horticultural Science – Looking to the Future

To celebrate 100 years of publishing, The Journal of Horticultural Science and Biotechnology hosted a conference where Professor Geoffrey Dixon welcomed more than 50 delegates and introduced the first speaker, Professor Simon Pearson of University of Lincoln, reports Clive Marlow.

Digital horticulture.

Professor Pearson began with an overview of the Lincoln Institute for Agri-Food Technology (LIAT). Through networking and its links with the UK’s agri-food companies they deliver applied research to industry. Much of the work they do is the application of Artificial Intelligence (AI) with robotics that will be needed post Brexit to replace some of the 135,000 EU citizens currently employed in the food manufacturing sector, including 64,000 fruit pickers.

As robotics become increasingly important in horticulture there will need to be greater cooperation between the plant breeders and machinery manufacturers to develop robotic pickers to harvest crops. Plant breeders will be required to select not only for yield, quality and disease resistance but new plant architecture that will allow suitability for harvesting by robots. With robots having such an important role, horticulture must not lose sight that it is all about people who must be able to communicate, from researchers to machinery manufacturers and growers to consumers and to the politicians.

It all starts with people, he stressed. Horticulture has an image problem and yet horticultural productivity per year has risen from £30K per worker in 2000 to £48K by 2017.

Securing water for horticulture.

Professor Jerry Knox of Cranfield University began his presentation by outlining the lessons that could be learned from 2018. Horticulture is highly dependant on water. It is a precious resource and horticulture must compete with industry, although currently only 2% of water is allocated to horticulture and agriculture.

Horticulture as an industry must develop a long- term strategy that is lacking at the moment. The water companies all have strategic plans. If we do nothing, we risk having one imposed on us and horticulture will be out-manoeuvred as demand for water increases from other industries, he said. We must work with the water companies or risk that water could be traded out to higher value users. One option is to share water resources as most water companies hold “Stranded Assets” i.e. high N water that could be used for horticulture.

2018 was an extreme year. In 80 years out of every 100 there is sufficient water, but in 2018 the drought was caused by a period of low rainfall and high temperatures. Growers must have a plan that assesses the risk to their enterprise from water shortages caused by back-to-back droughts.

Where is the sacrifice point when growers decide, due to water shortage, which crops to sacrifice and which to save using the limited water available, he asked? A water infrastructure needs to be built and an irrigation plan for the 80% years with rain-fed production systems for irrigation.

Salad growers could face having to use low quality water with the obvious risks. “Water availability is not confined to the UK; much of the fruit and vegetables we import are grown in areas of the world that are deprived of water,” he concluded.

Precision irrigation    

Dr Mark Else of NIAB-EMR who spoke on the “Precision irrigation of soft fruit to improve consistency of yield and berry quality,” continued the thread of efficient use of water. Based at East Malling WET Centre, Mark spoke about measures that growers could adopt by using tools and sensors. New water and fertiliser saving irrigation strategies are being developed for the soft fruit industry. These are derived from a detailed understanding of plant response to soil water stress.

There are a number of factors to consider including variety, plant density and development stage. Varieties have different responses to water shortages. Not all varieties are the same; in some varieties of strawberry there can be a 7% loss of yield due to the substrate drying out.

Precision irrigation technology for soft fruit includes moisture sensors in the coir, which if it falls too low, a logger will turn on the irrigation. Other sensors measure the EC with an alarm system that warns the grower if the crop is not getting enough water.

The Water Efficient Technology Centre located at the Fruit Focus site in Kent is developing rainwater harvesting techniques and using water more efficiently with a move to self-sufficiency reducing the reliance on other suppliers. In protected crops there can be a 50% variation of yield between leg row and centre row, indicating separate irrigation is needed.

Under fertigation it is important to match demand with supply and EC does not tell the complete story. Also, the WET Centre is working on variety specific crop forecasting models and predictions of the polytunnel aerial environment to improve ripening. Efficient water and fertiliser use will improve fruit yield, berry quality and lower picking costs, he concluded.

Fusarium diseases

Dr John Clarkson of the University of Warwick gave a presentation on Fusarium diseases, pathogen genetics and plant resistance. He explained the work of the genome-based approach for identification and diagnostics, emphasising the need for rapid identification to predict the risk of Fusarium diseases in horticultural crops.

Whilst Fusarium was present in most areas of lettuce production there was a new race, fusarium oxysporum lactucae,Race 4, that was causing concern to growers of protected crops. Races 2 and 3 are only found in Asia. Race 4 originated in the Netherlands in 2013, was confirmed in the Republic of Ireland and Lancashire in 2017, but in 2018 the disease had spread from Lancashire to Cambridgeshire. This race is particularly aggressive with the pathogen isolated from inside the taproot. Monitoring and early identification of the race is required to limit the spread of new outbreaks.