Developments in inorganic materials, synthetic organic materials and peat in soilless culture systems

Soilless substrates utilised in traditional hydroponics are often inorganic or synthetic materials, as opposed to organic substrate components utilised in other forms of soilless culture. As growers seek more precision production applications, more operations are shifting to soilless culture production for increased resource control. The standard substrate components utilised in soilless production have been well researched and engineered to fit into specific operations. Understanding the relationship between the substrate, water, and fertiliser in a container and knowing the movement within will allow for continued beneficial improvements in soilless culture and container horticulture industry. However, as we progress agricultural practices, new substrate materials optimised substrate materials must be developed. Here we present the traditional inorganic, synthetic organic materials and peat and how these components are developed, engineered, and processed.

Advances in soilless culture strawberry production

The majority of strawberries produced in the world are grown in the open field, and only in the past 50 years has protected cropping become established as a commercially viable system. Soilless culture (hydroponics) is an important component of this form of intensive production because it enables the strawberry crop to be grown above the ground (table top system) which can provides an improved root environment, nutrition and irrigation and at the same time easier fruit harvesting. Solid media systems predominate over liquid based systems with peat and coir being the most popular media. Future production appears to be increasingly towards year round production by the improved control of the plant environment, combined with reducing harvesting costs by robotic harvesting.

Advanced hydroponics design for plant cultivation in cities

The growth of the world urban population altogether with the detrimental effects of climate change and resource scarcity are currently exerting extreme pressure on our food systems. Innovation in vegetable crop production is being driven by plant cultivation technologies that are independent of soil fertility and availability, highly efficient in the use of water and mineral nutrients and adapted to protected environments with resilience to both biotic and abiotic stresses. Soilless culture systems (SCS) are most suited to tackle these challenges, and in recent years their innovation has mainly targeted the adaptation of the growing techniques developed in traditional commercial greenhouse systems into advanced hydroponic designs fitted to diverse urban environments. This chapter describes the most recent innovations in SCS for plant cultivation within urban settings. These include rooftop farms and cultivation inside buildings through the use of artificial lighting. Finally, the chapter looks ahead to future research trends in this area.

Soilless culture systems and growing media in horticulture: an overview

Soilless culture plant production presents a sector with unlimited potential for the horticulture industry. Soilless culture systems are environmentally friendly, resource-efficient, and support sustainable intensification in agriculture. Soilless culture system (SCS) crops in climate-controlled environments lead to higher crop production for the unit area and thus to a decrease in land usage in comparison to other cultivation methods. Here, we present the state-of-the-art of growing media and soilless culture and an outlook on further developments. For the future, it remains vital to identify and further develop sustainable materials, technologies and approaches, while keeping energy and production costs low and transportation distances short. The following chapters of this book provide further information and precise details, explaining step by step all these issues.

Advances in soilless culture of ornamentals

In the production of cut flowers and pot plants there are slow developments towards closed growing systems with recirculation of the surplus nutrient solution. In some countries, such as in The Netherlands, legislation to reduce discharges is a steering factor, as well as the advantages of a disease free start, higher potential production and quality. Crops such as rose and gerbera with less than 10 plants per m2 are now grown in completely closed growing systems and are on their way towards zero liquid discharge. Crops such as freesia, amaryllis and chrysanthemum, are still experimenting with soilless culture systems. Phalaenopsis is the most important pot plant grown in The Netherlands and is on the way towards a closed growing system. This chapter discusses the progress made, key challenges and how they are being overcome.

Advances in soilless cultivation of tomatoes and other fruit vegetables

Fruit vegetables are a rich nutritive source for the human diet and highly appreciated for their taste. Tomato, sweet pepper or cucumber crops have specific growth requirements linked to their physiology and their architecture (plant bearing fruits). Soilless culture system (SCS) are characterized by high performance, product quality and profitability for growers and solves agronomical issues such as input use efficiencies and out-of-season production. Recent advances in soilless cultivation of fruit vegetables are reviewed in this chapter: from climate and nutrients requirements to ‘speaking plant’-based approaches and establishment of fruit quality.

Advances in nutrient management modelling and nutrient concentration prediction for soilless culture systems

In closed-loop soilless culture systems (SCS), ion concentration and ionic balance are important factors to be considered for stable management of nutrient solutions. For maintaining appropriate ion concentration and ion balance, various techniques of nutrient analysis and prediction are required. Through nutrient management modelling, nutrient variations in the closed-loop soilless culture systems using nutrient replenishment methods can be better understood and predicted. Deep learning algorithms could be a methodology to predict ion concentrations using environments and growth data. A trained deep learning model has been found to accurately estimate ion concentration and balance in closed-loop SCS. Applications of theoretical modelling and artificial intelligence can thus be useful for the nutrient management of closed-loop SCS in greenhouses and vertical farms.

Advances in understanding plant root behaviour and rootzone management in soilless culture systems

A healthy and vigorous root system is essential in soilless plant cultivation. The primary function of roots in soilless systems is water and nutrient uptake. Root nutrient uptake has three characteristics: (1) selective, (2) accumulative, and (3) genotype dependent. Many factors can affect root health and root water and nutrient uptake. To create and maintain a healthy and vigorous root system, it is important to take an integrated rootzone management approach, considering the above characteristics and all the environmental factors. This chapter is a review of our current understanding of root, rootzone, and rootzone management in soilless systems; and it also discusses future research directions in this area.

Developments in alternative organic materials for growing media in soilless culture systems

There is increasing pressure on both growing media manufacturers and horticulturists to significantly reduce their reliance on peat as a constituent of substrates. This chapter distils down the available information on alternative organic materials which have emerged as the major contenders for peat dilution or replacement. We discuss materials coming from residues of manufacturing processes, for instance, wood, tree bark and coconut fibres and coir; waste and composted materials, for instance, green compost; and materials specially cultivated for use as growing media components, for instance, Sphagnum and Miscanthus. The future of growing media will be based on blends of different components which will be renewable and locally produced materials with better life cycle assessment.

Understanding and optimising the biological properties of growing media for soilless cultivation

The biological properties of growing media (GM) in soilless cultivation have been considered minor traits for decades. However, there is a growing demand for alternative, cheaper GM constituents, characterized by organic origin. A better understanding of the biological processes of GM is a key factor in developing improved functional properties in the next generation of “living” GM. This chapter reviews current knowledge about the biological properties of GM for soilless cultivations, paying attention on their importance for plant nutrition, and the influence exerted by weeds, pests/pathogens and beneficial microorganisms to promote crop performance and improve the ability of GM to suppress pests and diseases. More understanding of the relationship between GM, microbial communities and plants increases opportunities to develop sustainable strategies for disease control, fertilization efficiency and horticulture performance.