The Moraine Experiment provides a unique opportunity to study the development of soil organic carbon from an initially very carbon-poor parent material over a period of more than 60 years.
The experiment was established in 1964 under the leadership of Prof. Arnold Sau at the experimental field of the Estonian University of Life Sciences near Tartu. The aim was to investigate the development of soil organic matter and its changes under different crops and fertilisation regimes during long-term agricultural use. The experiment was later led by Prof. Rein Viiralt. Since 1980, agronomist Merike Kissa has been responsible for the practical management of the experiment.
A unique feature of the experiment is that, prior to its establishment, the soil was removed from the experimental area to a depth of approximately one metre and the area was filled with carbonate-rich glacial till poor in organic matter. The initial carbon concentration of the material was very low (1.28 g kg⁻¹). The soil has a sandy loam texture (62.2% sand, 23.9% silt, and 13.8% clay).
The experiment was established as a randomised block design. The experimental plots are isolated from each other along their sides to a depth of 1 m, and the sampling area of each plot is 1.5 m² (1 × 1.5 m). Depending on the treatment, there are 2–4 replicates. The experiment compares the effects of bare soil, spring barley, and permanent grasslands with different botanical compositions (a grass mixture and a legume–grass mixture) on soil organic carbon concentration and stock changes, as well as on plant productivity. The effects of mineral and organic fertilisers are also evaluated. The basic structure of the experiment has been maintained over the long term, although the plant composition and fertilisation schemes of some treatments have been modified during the experimental period. In 1995, two new legume species, fodder galega and hybrid lucerne, were introduced into the experiment. The permanent grassland swards have been periodically re-established due to weed infestation.
The main treatments of the experiment are:
1. Bare soil
2. Spring barley monoculture
3. Grass mixture
4. Grass–legume mixture
5. Hybrid lucerne
6. Fodder galega
The results from the first 50 years of the experiment were published by Kauer et al. (2019). The main findings showed that:
- Soil organic carbon stock increased on average by 0.35 ± 0.11 t C ha⁻¹ yr⁻¹.
- Even in bare soil, the soil organic carbon stock increased by 0.11 t C ha⁻¹ yr⁻¹.
- Perennial crops increased soil organic carbon stock more than annual crops.
For further information, please contact Karin Kauer ([email protected]) or prof Alar Astover ([email protected]).
