Variable and unfavourable winter conditions often cause damage and yield loss in grasslands in Northern Norway and other regions with long winters. Now, researchers are combining high-tech tools, models and ground registrations to predict winter survival and yields in grasslands in the region.
By: Siri Elise Dybdal // Norwegian Institute of Bioeconomy Research
Grasslands form the basis for fodder production for ruminants in large parts of the world, including Norway and Poland. However, climate change, with warmer and more unstable weather, have introduced new and greater challenges in forage production.
Variable winter weather and unstable snow conditions increase the risk of bare frost or prolonged ice cover on the ground, resulting in significant yield losses in grasslands, especially in northern and mountainous regions. Prolonged droughts and abnormally high summer temperatures are also increasingly problematic in many regions. In Poland, this has caused significant yield losses in grasslands, particularly on drought-prone soils.
In the project Tools for information to farmers on grasslands yields under stressed conditions to support management practices (GrasSAT), researchers from the Norwegian Institute of Bioeconomy Research (NIBIO) and NORCE Norwegian Research Centre have worked together with Poland’s Institute of Geodesy and Cartography and Poznań University of Life Sciences to adapt and combine high-tech tools such as remote sensing from satellites or drones, ground registrations, and process-based models.
In northern Norway, farmers and advisors from the Norwegian Agricultural Advisory Service (Norsk landbruksrådgivning, NLR) have contributed by selecting representative observation sites, recording data on snow, soil frost, winter survival, and yield, and providing information about practices such as reseeding, cutting, and fertilization.
The challenges of long winters
Agriculture in the northern regions operates under challenging conditions with a short, intense growing season and a long winter. Weather conditions vary significantly from year to year and between regions and locations, and the winter can be challenging for perennial grasslands. Frost, ice, and fungal diseases during the winter can, in some years, result in significant yield losses, leading to a substantial economic burden for farmers.
“The background of this project is these difficult conditions for grass production in northern Norway, as well as in Poland and other parts of the world. Winter stress causes great uncertainties for farmers,” says Tomas Persson, who leads NIBIO’s part of the project.
Persson points out that with climate change, winter conditions are projected to be even less stable, for example regarding snow cover.
“The problem is that you don’t know what you get. If the snow cover is less stable, or you have longer periods with cold weather with no snow cover, the plants will be exposed to much lower temperatures than if they were covered with an insulating layer of snow. Warm weather episodes during winter also increase the risk for build-up of impermeable ice covering the grass fields. This is particularly detrimental for grassland and can cause significant winter kill.”
More unstable conditions can also mean more frequent periods of low temperature early or late during the winter season when plants normally are less cold hardy than in the middle of the winter.
It is often challenging to predict winter damage and estimate the extent of the harm during the subsequent spring.
“Early warning of winter damage can help farmers plan measures in time to minimise losses. One aim of the project was to combine tools to get better prediction of the conditions in the spring. We wanted to predict the degree of winter stress and get better information for decision-making later.”
Thomas Persson, NIBIO
High tech tools
The researchers have combined different tools, such as satellite and drone images, and a process-based model (BASGRA) that simulates forage grass plant growth, and includes weather, soil and management data. This model can simulate the entire season – winter and summer – and predict winter kill incidents.
“It means you can get an early indication of the risk of winter kill. We have developed and adapted a system of tools for northern Norway, and have tested different means of acquiring data, calibrated the BASGRA model by combining data from ground registration and remote sensing from different times of the year such as the ground coverage in autumn and early spring,” Persson explains.
“Comparison with field measurements, such as plant height, leaf area and yield, helps calibrate and validate the results from satellite data. Additionally, satellite data can be integrated into plant growth models to continually update the models with new information throughout the season,” Persson highlights.
New for northern Norway
So far, project results indicate that adaptations of the BASGRA model for conditions in northern Norway regarding winter survival and growth can reduce prediction errors in crop (ground cover, growth patterns, yield) from 90% to approximately 20%.
Forecasting yield and quality during a cultivation season involves examining the effects of potential cultivation practices, such as fertilization, sowing and harvesting timing, in combination with weather and soil conditions. Additionally, it includes investigating potential long-term adaptations, considering factors such as climate change and the need for new varieties of crops.
Persson says combining these tools in research is new for this area of Norway.
“And to focus on the winter season is relatively new. Many are working in this field of research, combining remote sensing and satellite data, and crop growth models, but there is more work done for drought and heat stress. However, we must not underestimate the impact of winter stress, which can also affect other regions than those at high latitudes,” the NIBIO researcher underlines.
Useful for farmers and municipalities
The research in the project has been carried out in collaboration with NLR’s division in northern Norway, which helped select representative pasture areas from farmers in five regions: Nordreisa, Malangen, Målselv, Kvæfjord, and Sortland, with 4-5 pasture plots per region.
Ragnhild Renna, advisor at NLR North, has been involved in collecting ground data for the project.
“We have collected information on botanical composition, yield, and made field registrations,” she says.
Renna confirms that agriculture in the north of Norway is experiencing climate stress, and there is unpredictability concerning climate and weather.
“The information gathered in the project is highly valuable for considering the winter events and predicting the outcomes in spring. If technology can provide an advantage, and we avoid waiting for the snow to melt or temperatures to rise to see what condition the grassland is in, farmers can benefit.”
Ragnhild Renna, advisor at NLR North
Renna explains that when farmers have prior information on grassland conditions, they can start counteracting damage earlier. This lessens the risk of reduced yields and economic loss.
“This will benefit the process of procuring the necessary resources and calculating needs such as buying seed or avoiding buying fertilizer if alternative renewal measures are required. Knowing about the conditions beforehand will allow farmers to assess both what is needed and how much.”
“There’s also the aspect of planning barnyard production that requires forage. For example, the model might help farmers decide whether they should plan to acquire more land. That could be another advantage,” she says.
Renna also believes municipalities could potentially use this tool for administrative purposes.
“They could benefit from being able to check for available land when planning, and concerning compensation schemes for crop failure. Farmers bear the responsibility of reporting potential crop failure as early as possible, but municipalities could contribute to assessments of potential outcomes,” she points out.
The agricultural advisor also says the information on both winter and summer stress is useful in the north.
“This growing season, we have experienced winter stress, as well as drought stress such as in Poland. The tool encompasses numerous elements that are proving useful for Norwegian farmers,” she concludes.