Horticulture: Top 5 Technologies for Sustainable Crops

Horticultural crops require more direct attention and monitoring per plant than arable crops, to ensure any emerging pests and diseases are limited to an acceptable threshold. The establishment of this intensive but integrated management approach paved the way for technological improvements that automated and optimised the farm operations that were previously performed manually, introducing more precision and reliability [1].

1. Automation for plant monitoring

Crop scouting is a crucial step in pest and disease management. It allows the farmer to make timely decisions and take preventative measures. It saves time and money, allows trends to be identified, and predicts future threats and potential problems. Typical equipment for plant monitoring in a field or greenhouse includes: a magnifying glass, plastic bag for plant samples, clipboard, marker, and camera [2]. Today, sticky traps and mobile apps can give a far more accurate picture of the pests and diseases in a crop; some apps even provide suggestions for possible solutions [3].

A recent innovation has been the development of digital scouting applications for mobile devices (video hosted on Youtube) that provide a monitoring platform for the registration of diseases, and offer biological solutions for horticulture. A scanner may count the insects on sticky cards using accurate image recognition, for example. In this way, you can scan the sticky traps in a crop, while the dashboard on a desktop/laptop gives a direct schematic overview of the results. The data can then be collated with other measurements and a broad analysis can provide suggestions for biological solutions. The app can also have machine or deep learning capability which allows it to improve its predictive power over time.

2. Use of drones for pest and disease identification and management

Drones, or Unmanned Aerial Vehicles (UAV), that can identify pest and disease ‘hotspots’ in crops and then accurately disperse beneficial insects from the air, are now in use. Drones with sensor and imaging capabilities will be playing an increasingly critical role in identifying and reducing crop damage in the coming years [4]. An innovative release mechanism designed for the aerial release of beneficial insects (biological organisms) can now be attached to a drone to disperse this biological solution exactly where it is needed most in the crop. Drones equipped with a scouting device can also be used to remotely locate and identify pests and diseases [5] [6].

The specially adapted drones, that may have a wingspan of 1.5 m, can lift 15 kg, and fly over a 20-hectare strawberry field in an hour and disperse beneficial biological organisms. These drones are more accurate than man-handled equipment and can target specific areas or ‘hotspots’ of pests or diseases (video hosted on Youtube).

What started out as military technology for observing and targeting specific enemy locations is now being used as a tool for sustainable agriculture.

3. Alternatives to traditional growth in soil

Technology is revolutionising the demand for natural resources such as water and land.

In hydroponics, plants are grown in a small amount of solid matter, mainly sand and gravel (Figure 1).

Figure 1: Hydroponics © Alachua County Source

A recyclable solution (video hosted on Youtube) provides the exact amount of nutrients required by the plant, reduces water consumption by 90%, and results in reduced pest problems [7] [8]. The most popular crops grown in hydroponics are leaf lettuce, tomatoes, peppers, strawberries, and herbs [9].

Aeroponics uses a moist atmospheric environment within which the plant grows with nutrients being sprayed on the roots [10] [11]. These methods allow us to grow in the most difficult environments (video hosted on Youtube), such as underground or in polluted cities.

The use of vertical farming (growing low crops in multiple layers, mostly inside buildings) and urban farming (the growing of plants within and around cities), combined with technologies such as hydroponics, allows us to make efficient use of space and reduce the distance our food travels to get to consumers. Another new and interesting development in Japan uses a biopolymer for ‘film-farming’. According to its creators, the film uses 90% less water than conventional farming and offers a viable alternative to resource-intensive agriculture.

4. Symbiotic organisms and plant defences: Biocontrol

Research is focusing on how microorganisms promoting plant growth can be applied from the start of the cultivation cycle. These can enrich the microbial composition of the environment around the roots of the plants. Beneficial microbes can activate the defence systems of plants and make them grow stronger [12] [13]. When they live on or near the root system they also compete for nutrients and space with pathogens (these are microorganisms that can cause diseases). Trichoderma (Figure 2) for instance, has a direct effect on the pathogen both through predation, and by exuding antibiotic substances in the root zone. Microbial pesticides that are designed to work on foliage pests invade the destructive organism (often at larval stage) and use its tissue as food.

The application of substances via a seed coating is an efficient way to apply beneficial microorganisms to crops (video hosted on Youtube). Biopesticides have also been developed in this way to support the plant.

Figure 2: The fungus Trichoderma harzianum colonizes roots. It stimulates plant growth and gives resistance to a wide range of adverse environmental conditions © Koppert Biological Systems

There are three categories of microbial biopesticides.

1. bacteria
2. fungi, and
3. oomycetes or even viruses.

Biopesticides provide a wide range of tools for non-chemical pest and disease control but are tightly regulated. All products have to be registered in the country of application.

5. Precision agriculture for weed control, soil health and better yields

The need to produce more food in a sustainable manner has led to widespread adoption of ‘precision agriculture’. This term describes a range of practices that use technology to provide crops with precisely (no more and no less than is necessary) the amount of nutrients and treatments needed for a high yield [14]. Automation avoids over-application of agrochemicals which saves money and reduces spill-over to the wider environment (eg nutrient leaching) and predictive technologies can help customise crop varieties for improved performance [15]. Here are two examples: the blue river technology (a precision weed control machine) (video hosted on Youtube) and how to enhance soil health and pepper yield on a farm with salinity issues (video hosted on Youtube).

References can be found under the ‘Downloads’ heading at the bottom of this Step.