Carbon storage in long- and short-term grasslands

The most central research tasks are:

• to measure C content up to 60-70 cm depth in long- and short-term grasslands under contrasting climate, soil and management conditions;
• to describe C distribution in soil profile also with help of hyperspectral images;
• to estimate C storage in main forage production regions of Norway;
• to integrate historical and new data by modelling, and to predict C sequestration under future climatic condition;
• to investigate the role of earthworms and fungi in the distribution and storage of carbon in grassland soils with differing management history
• to calculate the economic value of maintaining C in grassland.
• Disseminate the findings to agricultural authorities, farmers and other stakeholders

The project will collaborate with the project ‘’Longtermgrass’’ that focus on forage quantity and quality and based on the existing long-term grassland experiments. These experiments represent silty and peat soils that are representative for coastal temperate and arctic areas of Norway. The project uses an integrated approach, combining experimental work, hyperspectral imaging, GIS and model-based methods.

Work Packages

WP.1: Carbon content in long- and short-term grassland soils down to 60-70 cm depth

This part of the project will provide answers to the following questions:

• to what degree age of grassland and management practices affect C storage/losses?
• which management system is most beneficial to maintain or enhance C stocks

Hypothesis: Long-term grassland store more C than short-term grassland and C storage capacity at the northern sites will exceed those of the southern site

WP.2: Carbon accumulation and distribution in soil profile

Long-term field experiments described in WP1 will be used to assess effect of management practise in grasslands C distribution in soil profile.
We hypothesise that in treatments subjected to regular ploughing C concentration will be homogenously distributed in the plough layer and will decrease with depth in the subsoil. In treatments that have not been ploughed for more than 20 years, C concentration will mostly decrease with depth due to recent re-accumulation of organic matter in surface. Traces of the old plough layer will generate a discontinuity in the carbon profile at the interface between the topsoil and subsoil. The longer the period without ploughing the higher the surface C concentration.

WP3: Carbon mapping in highly concentrated forage production areas in Western and Northern Norway 

Based on data protocols from soil samples collected by farmers and analysed by Eurofins (a company that provide for soil chemical analyses) we are able to quantify C content in soil down to 30 cm. In WP3, we will systemise and map C content in the grasslands located in Western and Northern Norway where meat and milk production are highly dominated. The data will be visualised by GIS and the map of C content in grassland soils will be developed. This map will be available to agricultural authorities, farmers, agriculture extension service throughout NIBIO’s home page and services.

WP4: Models that increase our understanding on climate change and C sequestration

In this work package we will evaluate the time domain of management-induced soil carbon changes according to the hypotheses in WP1 . A dynamic model approach (ICBM) will be used to study the effects of management on  rassland
soil carbon stocks. ICBM was developed as a minimum approach for  calculating soil carbon balances in a 30-year perspective (Andrén and Kätterer, 1997). The model has been calibrated and validated for several long-term field data sets, especially under Nordic conditions (e.g. Kätterer et
al., 2004; Juston et al., 2010; Bolinder et al., 2012) and has been extended to a regional approach  which is used in the Swedish national climate reporting of soil carbon changes (Andrén et al., 2008). The ICBM model is also included in farmers’ advice packages such as HOLOS (Kröbel et al., 2015). In this project, the model will be calibrated with data from the Norwegian long-term grassland experiments and the effect of management on soil carbon stocks will be estimated. A priori knowledge from other long-term field experiments under similar climatic conditions in Sweden, Island, UK and Eastern Canada will also be considered (Kätterer et al., 2012).

WP5 Profitability and economic value of C sequestration

The economic trade-offs between existing practices and the practices required to store carbon may constrain the potential to enhance carbon sequestration. For example, adopting long-term grassland practices results in additional carbon storage over short-term grasslands. Renewal result in loss of yield in the seeding year, and ploughing is costly and time consuming. However, long-term grassland will also result in reduced grass yields that may reduce the
farmer’s profit. We will estimate the necessary incentive—the price per ton of carbon—to induce farmers to store additional carbon in their lands through financial examination of different grassland management practices (by generating assumptions about profit maximization). Differences between strategies derived from WP4 will be the main data source. We aim at using the simulation model of forage production and utilization to be developed in the ForEff project (with extensions to e.g. cope with the C sequestration issue) in
the economic valuation. One major difficulty in assessing the production of grass and forage (as inputs into livestock production processes) is the lack of any clear monetary value to place on the grass output. A range of prices will be used (taking the specific feed qualities into account), to examine whether the management practices are sensitive to the valuation of the grass output. The sensitivity analysis allows a test of the robustness that can be placed on the conclusions.

WP6. The role of earthworms and fungi in soil carbon storage and distribution

It is well known that earthworms and fungi decompose organic matter from plants and the products thereof become more intimately integrated into the soil matrix. In this WP we will conduct surveys of earthworm density, burrow proliferation, and fungal diversity and compare results between pastures which have not been tilled since 1968 and pastures tilled every 3-6 years.

WP7 Disseminate the findings to farmers and other stakeholders

Results and knowledge from former and current projects will be disseminated to farmers, advisory services and agricultural authorities through different channels:

1) Soil profile demonstrations at Særhaim, Fureneset and Svanhovd in cooperation with the project LONGTERMGRASS and Norwegian Agricultural Extension Service (NLR). One demonstration per year at different regions for three years. We will also cooperate with Dr Riley (long-term experiment at Møystad).

2) Regional and local seminars in cooperation with NLR and Norwegian Farmers association about how management systems affect C storage

3) Articles in professional journals (e. g. Bondevennen, Norsk Landbruk, Samvirke)

4) Lectures at national and regional meetings (e.g. meetings arranged by farmers organisation and county agricultural authorities)

5) Project information at the web site of NIBIO

6) Participation in international conferences and publications in peer-reviewed journals