- What are the soil characteristics in the regions where the sampling campaign is conducted?
Only 13% of all soils in Switzerland have been classified to date. In 2025, we want to classify the soils at our sampling sites and integrate the results into the ongoing development of the Swiss soil map.
On the mountain slopes, the soils are shallow; in the valleys, the soils consist of relatively deep alluvial deposits of rock, gravel, and fine material. Human influence and the river Rhine have considerably changed the landscape in the valleys. The alluvial soils are nutrient-rich and fertile and offer favorable conditions for agriculture. The average annual temperature in the region is XX°C, and the amount of precipitation is XXXX mm, with the most rainfall occurring in summer.
- What unique factors influence the composition and structure of the soil in each of these regions?
Mountains and valleys characterize the Alpine region. The valleys’ geological material originates from the rocks’ weathering in the mountain areas. The Landquart area is the historic Rhine delta to Lake Constance, which has alluvial deposits from river fans. The Trin area was formed by a rockslide 10,000 years ago and is still changing due to landslides and erosion. The rock consists of Mesozoic limestone, including marl. The highest sampling area is about 2000 meters above sea level and is characterized by scattered and shallow soils.
- Did you face any challenges related to each region’s specific climatic or geographical conditions? What challenges? How did you face these challenges?
Soil sampling is always a difficult task. However, this sampling campaign was highly challenging. Apart from the logistic challenge of the alpine sampling area being 250 km away, there were serious challenges due to the climate and geology of the chosen location. Spontaneous adaptability is needed to adapt to changing situations, such as untypical weather conditions for the season (above average precipitation rates, below average temperature including snowfall and frost). We had to work more than 60 hours a week with changing teams of up to 14 people.
The time windows for sampling were also limited by the schedules of the farmers who had carried out seasonal work in their fields. This also applied to the grassland areas, which were mown to produce hay and fertilized with liquid manure after each cut.
- How does this soil sampling campaign differ from other soil sampling campaigns? Can you indicate the main difficulties you encountered during a big soil sampling like this?
The main difference to our regular sampling campaigns is the large number of samples covering a large area and the numerous sample types taken simultaneously. At each of the five sites, we had fields with three intensity levels, where we took a series of different soil samples at each of the ten sampling points. It took a long time to collect all the samples, bandieve, dry, cool, or freeze them before they could be packaged and dispatched on time. For some, this meant working for several weeks without a break.
- What impact do you anticipate the climate change experiments will have on soil and its biodiversity?
The climate change experiment is designed to increase the temperature and reduce the precipitation in a relatively small experimental area. Plants and other organisms are expected to come under stress, and their composition could change. The outcome will depend on the behavior of the various species and how they can cope with heat or drought. Some species may flee from unfavorable conditions; others may protect themselves or rely on specific physiological mechanisms to adapt.
- What factors can increase the diversity of soil organisms? And which ones decrease it?
The living soil is composed of organisms that are secondary producers and thus live off the primary production via plant photosynthesis – the availability of carbon or energy limits them. Mimicking a climate change scenario, we investigate the effect of rainfall reduction and temperature increase, influencing plant growth conditions and soil biota. A lack of biomass leads to a decrease in the abundance of sensitive decomposer species and, thus, a decrease in diversity when plants are stressed due to climate change. More biomass will support an active soil life dominated by fast-growing organisms so that diversity will decrease, but only in the short term. Over more extended periods, a rich and diverse edaphic community will develop.
- Who ‘prepared the ground’ and made conditions ready for the soil sampling?
Our project partner from The Research Institute of Organic Agriculture (FiBL) was in charge of the soil sampling campaign in the Alpine region.
