Leaching / lysimeter

Auswaschung Lysimeter

Lysimeters are cylindrical containers filled with natural soil. The water percolating into the soil can be collected at the bottom of these containers. Agroscope’s lysimeters are used to study the water- and mass balance of agricultural soils. In this video, you’ll discover the largest and most modern lysimeter installation in Europe, which has been at Agroscope since 2009.

When a soil is water-saturated and more precipitation falls than is absorbed by plants and than evaporates from the soil, the seepage water percolates to greater depths and reaches the outlet at the bottom of the lysimeter. Here, the seepage volume is measured with a tipping bucket. The seepage water contains readily soluble substances leached from the soil. With each tip, a small amount of water flows into a sample bottle. Every second week a water sample is analysed for various substances, with the emphasis being on nitrate. 

Some lysimeters stand on a scale which records their weight every 5 minutes. Through changes in weight and the seepage volume, the amount of precipitation and evapotranspiration over a given period of time can be calculated. The collection of this data and the measurement of water content at different lysimeter soil depths via probes, provides information on the water consumption of crops.

Agroscope’s Lysimeter Facilities

Agroscope operates two facilities with large lysimeters: one with 72 vessels (‘ Ly72’) and one with 12 vessels (‘Ly12’). 

Site Zürich-Reckenholz 
Altitude 440 m.a.s.l.
Annual precipitation 1054 mm (standard value of the period 1981-2010)
Annual temperature 9.4 °C (standard value of the period 1981-2010)
  ‘Ly72’ facility ‘Ly12’ facility
Start-up 2009  1980
Vessel size 1 m2 in area
1.50 m deepiques

3 m2 in area
2.50 m deep

Weight 3 tonnes 14 tonnes
Soils

All monoliths
(soil columns cut from a field)

  • Cambisol from Grafenried (BE) (48 vessels)
  • Pseudogleyed Cambisol from Zurich-Reckenholz (ZH) (12 vessels)
  • Luvisol from Schafisheim (AG) (12 vessels)

backfilled soils

  • calcaric Cambisol on gravel (6 vessels)
  • Cambisol on moraine (6 vessels)

Nitrate Leaching under Arable Crops

Our multi-year trials with arable crops aim to quantify the amount of nitrate leached from the soil with a particular form of agricultural management. Here, the focus is on examining various farming systems (PEP, organic farming), cover crops (with different sowing and ploughing times), tillage (plough, mulch seed), fertilisation variants (reduced and increased nitrogen fertilisation) and soil types.

Co-workers: Ernst Spiess, Volker Prasuhn, Clay Humphrys, Karin Meier-Zimmermann, Frank Liebisch 

Nitrate Leaching under Vegetable Crops

Since 2017, the Ly12 facility has been used to study the level of nitrate leaching under a vegetable crop rotation, as well as the influence of crop-residue management (leaving crop residues on the lysimeters vs. removal of same) on losses. This trial is being conducted within the ‘NitroGäu’ research programme for the nitrate project in the ‘Gäu-Olten’ region (canton of Solothurn).

Co-workers: Ernst Spiess, Clay Humphrys, Reto Neuweiler, Volker Prasuhn, Frank Liebisch, Karin Meier-Zimmermann

Optimal Use of Recycling Fertilisers in Organic Farming (Recycle4Bio)

The production and use of recycling fertilisers from biogas facilities are steadily increasing throughout Switzerland; however, many questions regarding the medium-term impact on yields and nitrogen use-efficiency and losses remain unanswered. In addition, data from multi-year field trials on the pros and cons of the combination of recycling fertilisers and biochar is lacking.

The aim of the project is to investigate and optimise the impact on yield as well as the nitrogen-use efficiency of recycling fertilisers in organic production systems. The effects on soil- and product quality and on nitrate leaching will also be examined. To this end, a multi-year precision trial with different recycling fertilisers (biogas slurry with co-substrate, solid digestate and compost produced from the latter) with or without the addition of biochar, was set up. At the same time, the processes with liquid fertilisers were tested for source-specific nitrate leaching in 12 vessels of the Ly72 facility by means of 15N stable isotope labelling.

This is a joint project of the Research Institute of Organic Agriculture (FiBL) and Agroscope, sponsored by the Federal Office for Agriculture. 

Co-workers: Jochen Mayer, Michael Scheifele, Else Bünemann (FiBL), sowie Feld- und Labortechniker von FiBL und Agroscope

Assessment of micropollutant degradation using multi-element compound-specific isotope analysis

In this SNSF Sinergia project, a new method was developed for detecting the breakdown of plant-protection products in groundwater. Agroscope made the Ly12 facility available for this purpose. After application, various PPPs and their metabolites were analysed in the soil water and the seepage water.

The project was conducted together with the Centre for Hydrogeology and Geothermal Energy of the University of Neuchatel (D. Hunkeler), EAWAG (T. Hofstetter, H.P. Kohler) and the Munich Helmholtz Centre (M. Elsner).

Co-workers: Volker Prasuhn, diverse Externe

SNF: Assessment of micropollutant degradation using multi-element compound-specific isotope analysis