To further the green transition and a sustainable agriculture in the region, the European Union aims to decrease the use of mineral fertilisers and pesticides. But this has consequences for the local horticultural production and in the Baltics and Nordics where the self-sufficiency level of fruits and vegetables is already low, this can cause problems.
“In Estonia for example, only about 10 to 12 percent of all fruit we consume are local. And if we now ask farmers to reduce the use of fertilisers and pesticides, we are afraid that the production will decrease, so we have even less local fruits”, says Ulvi Moor from the Estonian University of Life Sciences.
Moor leads the research project Innovative sustainable Nordic-Baltic horticulture (InNoBaHort) that aims to find solutions to the dilemma of reducing the use of mineral fertilisers and pesticides without negatively impacting the local fruit, berry and vegetable production in the Nordic and Baltic regions.
“Local fruits are very important in a healthy diet and more sustainable because they are not transported from the other side of the world, so we need to sustain the local production. The aim of our project is to help farmers make science-based decisions”, says Moor.
The project is a collaboration between research teams in Estonia, Finland, Sweden, Norway and Lithuania. They work on two main topics, to decrease fertilisation and reduce the need for plant protection. The focus of the project is on strawberries, apples and blackcurrants.
“These fruits and berries are most important for our region. Apples are the only fruits which we can consume almost all year round here and blackcurrants and strawberries are the main berry crops in our climate”, says Moor.
Less nitrogen, same yield?
The Finnish and Estonian teams are collaboratively working on developing a fertilisation management plan for farmers through the analysis of leaf samples.
“We do leaf analysis with a modern technology using X-ray spectrometer, which enables to get results much faster than conventional methods. Leaf analysis reflects the nutritional status of plants more accurately than soil analysis. We look at what elements are deficient and what are some that can be reduced so we find an optimal range and can tell the farmers how much fertilisation is sufficient”, Moor explains.
The researchers are testing different nitrogen levels for strawberry production in Finland and Estonia because the environmental impact of mineral nitrogen fertilisers is very high.
“Our experiments will continue for another year, but we have already seen that even if we reduce the amount of nitrogen by as much as one third in strawberries, the yield does not decrease. So, it may be possible to use less nitrogen in the future, but first we need to make sure it doesn't affect the fruit quality. For example, the sugar content of strawberries may decrease if the amount of nitrogen in the fertiliser is reduced. But hopefully not so much that the consumer will notice any difference in the taste of the strawberries”, says Moor.
Innovative plant protection
The team in Lithuania is working on plant protection, specifically on the protection of strawberries from their main risk, which is Botrytis cinerea, so called gray mold.
“Usually, this disease is tackled with synthetic fungicides, but the Lithuanian team tries to replace those with biological alternatives. They have developed bacteria preparations and plant-based extracts. The results are very promising, in experiments the plant-based preparations were more effective than chemical treatment on one cultivar. These plant-based pesticides are not commercial products yet, but the results give us hope that we in the future can replace some synthetic fungicides with biological products”, says Ulvi Moor.
Meanwhile the project teams in Sweden and Norway are leading research of the fungal disease European canker caused by the fungus Neonectria ditissima. The disease is a big issue for apples in the Nordics and Baltics. The Swedish group is studying the pathogenicity of the fungus and susceptibility of different apple cultivars to Neonectria ditissima.
“There is no information about which cultivars in Estonia are susceptible. Our Estonian PhD student is therefore collaborating with the team in Sweden on this, and at the same time has the valuable opportunity to work together with experienced scientists in this field. To understand the virulence of the disease and the susceptibility of the cultivars, DNA is extracted from lesions on apple trees from different countries and inoculation experiments are carried out. The aim is to find cultivars that are less susceptible and then use these for breeding. There are no good plant protection chemicals that help against this disease so trying to create more resistant cultivars is very important”, Moor says.
New model predicts disease spread
Another research group based in Norway is developing disease forecasting model for European canker on apples and Mycosphaerella leaf spot (Mycosphaerella ribis) in blackcurrants. They are using spore trap data from Finland and Norway and data from local weather stations to model and predict the spread of diseases.
“The model helps to predict when the spores are released and when they are most likely to end up in the orchard and infect the trees based on temperature and precipitation. This helps the farmers to be more precise with spraying fungicides and to avoid unnecessary spraying.”
