Horticultural Production Physiology

Last changed: 30 December 2018

The research within horticultural production physiology aims at increasing the knowledge of how to, in long-term sustainable production systems, steer horticultural crops to the desired development by varying the external conditions.

Production of horticultural crops are characterized by a high degree of control of the outer conditions of the locality of the plant. Depending on whether we cultivate in greenhouse or in the open, there are varying conditions to steer different factors according to the plants’ need for, for instance, light, temperature, water, plant nutrition and substrate. The purpose of steering these factors is to optimize the cultivation conditions for the plant, but also to optimize the production from an economic and environmental perspective. 

The aim of the research is partly to be able to provide horticulture and society with knowledge in order to continue developing efficient and environmentally sustainable cultivation systems, and partly to study the plants reactions to varying factors from a more basic research perspective.

The projects within the division of horticultural production physiology study both eatable garden horticultural plants such as vegetables, fruit and berries, and ornamental plants such as potted plants, cutting flowers and nursery-garden plants. We have modern research greenhouses and climate chambers to our disposal, but also possibilities for trials in the open.

Focus areas:

Production of berries and grapevines

At Rånna experimental station, several field trials with berries are conducted. Plant protection in organic production of raspberries in tunnels is a project running 2012-2014 which also is a part of the Interreg project Climafruit. More than 200 berry bushes and fruit trees of new cultivars are planted at Rånna during 2012-2014 for evaluation and quality assurance. Organic production of highbush blueberries in tunnel and in the open is a project designed to explore the development of three cultivars of highbush blueberries in two different substrates. Project focusing integrated pest management in strawberries is running continuously in collaboration with advisors and growers.

Organic production

Organic greenhouse production is challenging, as volumes of growing media are often limited, or in the case of soil-bound production, the possibilities for crop rotation are restricted. The major challenge regarding fertilization is the fact that the mineralization of nutrients from organic nutrient sources is low and hard to predict, thus causing mismatch between uptake and availability. In current projects, financed by Expansion in Horticulture and C.F. Lundströms foundation, we study the availability for nutrients by using mixtures of different nutrient sources, and different climatic conditions.

Phosphorus efficiency

Phosphorus is a limited resource and may cause problems with eutrofication and algal blooms both in freshwater and in the Baltic sea. We are studying how the utilization of soil and fertilizer phosphorus can be improved for plants grown in the greenhouse or in the field.

Microalgae

Algae is a term for a large and diverse group of organisms. It contains both macroalgae, multicellular photosynthetic organisms found in water, and microalgae - unicellular algae that are so small that they can only be seen under a microscope. This group includes both organisms have a very simple bacteria-like cell structure whose proper name is cyanobacteria and those with a more advanced cell structure with a nucleus. Microalgae can be, just like macro algae and plants, capture the energy of sunlight through photosynthesis (autotrophs) and there are also species that are capable of obtaining energy through degradation of organic compounds (heterotrophs).

In recent years, interest in the microalgae has grown. Many microalgae produce commercially valuable metabolites and there is a big market for those in the food and health sector. But the growing interest is not only due to the interesting metabolite production but also that the microalgae can perform important ecosystem services. One example is reduction of nitrogen and phosphorus concentration in water during their growth, i.e. they are a tool to decrease eutrophication. A further advantage is that carbon dioxide is consumed during growth and that energy is supplied via solar radiation. If the biomass is then used in an anaerobic digestion process to produce biogas and later as a fertilizer the nutrients has a potential to be recirculated. Algae also have the potential to be used in different remediation processes because of absorption of certain substances such as heavy metals.

In ongoing research in the Department of Biosystems and Technology, we work with issues related to microalgae and the green sector. How can we reduce the leaching of nutrients using microalgae? How can the nutrients be returned to a cultivation system using microalgae? How can microalge be used to decrease contaminates in the ecosystem? Can the cultivation of microalgae in order to obtain certain metabolites be a possibility in the horticultural sector?

Mykorrhiza

Most agricultural and horticultural plants can create symbiosis with mycorrhiza mushrooms. The mushroom can contribute to the uptake of nutrients of the host plant, and can also provide protection from different types of stress and diseases. Sometimes, however, high levels of plant nutrients in arable land or cultivation substrates may inhibit the formation of mycorrhiza on cultivated plants.

Cultivation substrates with a poor ability to bind nutrients are often used in greenhouses and nursery-gardens. We investigate whether mycorrhiza can be established on plants in different types of cultivation substrates in organic and conventional cultivation systems through inoculation with mycorrhiza mushrooms in combination with reduced levels of nutrients. If it is possible to grow vegetables with mycorrhiza at lower fertilizer levels, both the fertilizer costs and the risk of nutrient loss is reduced. We also study presence and impact of mycorrhiza for plants grown in the open.

Organic residues

The sustainable society must be resource-efficient and organic wastes recycled as far as possible. During decomposition processes organic matter is degraded into simpler components that can be reused. The degradation process is different depending on the chemical composition of the material and the environment in which it takes place.

Biofertiliser produced in the biogas process is an example of an organic waste which is recycled when it is returned to the field. In our research, we investigate the possibility of using biofertilizer in other cropping systems such as hydroponics and algaculture. Organic waste is not limited to this but there is a wide choice of residues originating from e.g. food industry and forestry. The organisms which we use in our research are plants, algae and fungi.

In addition to recycling in order to achieve resource-efficiency, also health- and safety issues are important aspects. Consideration must be given to harmful substances, e.g. heavy metals and persistent substances such as certain pesticides, which can be present in the organic matter and thus accumulates to harmful levels. In the research we do on organic waste products, and how they can be recycled, the aspect of safety and risk of accumulation is always included.

Micronutrients and heavy metals

We have studied the uptake of heavy metals, like cadmium, in several plant species like potato, carrots and lettuce. As the solubility of cadmium in the soil solution increases at low pH, the choice of N-fertilizers in particular may affect the uptake of cadmium. We have investigated the influence of nitrogen form on cadmium uptake in both nutrient solution and field experiments. 

Calcium – Potassium - Magnesium

Calcium deficiency in potato tubers may result in impaired quality such as internal brown spot, hollow heart and an increased sensitivity for blue spot. Soils usually contain high amounts of calcium, but in forms unavailable to the tubers. To be able to find the calcium strategy that gives the highest calcium concentration in tubers, we grow potatoes both in field and pot trials. We also study the interaction between calcium and boron since the uptake of these essential substances is affected by each other.

Greenhouse climate

The LED-technology is developing rapidly and has in recent years become more attractive for use in greenhouse crop production. The freedom of choice regarding the spectral distribution of the light and the design of the fittings opens up new possibilities for the use of light within protected horticulture. In the current projects the LED-technology is adapted for use in greenhouse horticulture. We are developing light strategies for reduced consumption of energy and chemical growth retardants.

Research Projects:

Ongoing

Horticultural Production Physiology
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