is short for “Soil as a sustainable resource for the bioeconomy”

BonaRes Soil³: Sustainable Subsoil Management

Project goals

The aim of the overall project is to utilise the volume of the subsoil better than before for plant growth in order to increase or at least secure crop yields. We assume that nutrient and water uptake from the subsoil will be improved if the plants invest more in roots in the subsoil. This can be achieved through lower physical resistance for root canals, "hot spots" of nutrients or plant-available water in the subsoil when the topsoil is seasonally dry.

Root scan to determine the root length
Root scan to determine the root length © Christian Dahn


Die wachsende Weltbevölkerung macht eine Steigerung der Nahrungsmittelproduktion um mehr als 60 % bis zum Jahre 2050 verglichen mit 2005/2007 nötig. Vor dem Hintergrund der jetzigen Ausgangslage weltweiter agrarischer Produktion, ist eine „nachhaltige Intensivierung“ der Landwirtschaft eine große Herausforderung. Dafür bietet der Unterboden ein großes Ertragspotenzial, da große Mengen der Wasser-, Kohlenstoff- und Nährstoffvorräte im Unterboden gespeichert sind. Um das Ertragspotential unserer Böden zu sichern und ihre Produktivität auf lange Sicht zu steigern, ist es daher unausweichlich den Unterboden in Zukunft miteinzubeziehen.

Results outlook

The aim is to develop a scientific basis for practitioners. This is achieved by

  1. dovetailing research and production strategies, services,
  2. Strategic cultivation planning,
  3. success monitoring and
  4. the provision of software.

The indicator systems for water and nutrient acquisition developed in Phase I offer a tool for monitoring success. The technical procedures offer potential for economic connectivity in neighbouring disciplines. The methods for identifying genotypes provide potential starting points for commercial plant breeding.

Interim results from phases 1 and 2

The physical and chemical properties of the subsoil are more heterogeneous than those of the topsoil. Root access to the subsoil depends on the location, but can be promoted by topsoil management, in particular nitrogen fertilisation and liming, as well as by biopores and loosening, which leads to positive yield effects under seasonal drought conditions. For targeted subsoil management, we have developed a tool for adding compost to the subsoil in strips. This enables yields to be maintained or even increased by 20%, depending on weather conditions and topsoil management. Subsoil management is most promising and sustainable in well-drained sandy soils, regions with layers that restrict root growth and regions with extreme climate changes. The integration of subsoil management may be most feasible under clear tenure conditions and in organic farming.

Positive effects of strip-wise subsoil melioration with compost incorporation in terms of yields and soil quality, such as microbial community, nutrient status and carbon storage, persist for at least 4 years. In addition, no increased nitrogen leaching was observed. With input costs of €800/ha and yield increases of between 23 and 55%, the technique pays for itself after 4 years. Subsoil melioration could make 45-60% of the nutrient and water reserves in German arable soil accessible to crops, with the most promising results in north-east Germany, which is characterised by summer drought. The acceptance of subsoil melioration by farmers varies in different regions and is generally higher for biological techniques (biopore formation by preceding crops) than for more invasive technical methods.

Outlook for results phase 3

Our aim is to

i) determine the longevity of yield increases and soil quality (carbon, water and nutrient retention) from mechanical and biological subsoil improvement,

ii) evaluate water and nutrient use efficiency against conventional tillage,

iii) provide a systematic tool for the choice of organic amendment,

iv) monitor the performance of different crops after subsoil improvement and

v) determine the costs, risks and benefits on a regional scale. This will allow us to provide application advice and information material to the public, farmers, industry and academia.

Project titel: Soil³ Nachhaltiges Unterbodenmanagement (Förderkennzeichen: 031B1066)
Acronym: BONARES

2015-2018 (Phase I)

2018-2021 (Phase II)


Bundesministerium für Bildung und Forschung

Project aims:
  • Investigation of long-term management effects on biopore densities in the subsoil
  • Investigation of the potential of biological and technical subsoil melioration
  • Identification of subsoil-efficient varieties
Project partners: Projektleitung: Prof. Dr. Wulf Amelung, INRES-Bodenwissenschaften, Universität Bonn
Prof. Dr. Frank Ewert, Dr. Thomas Gaiser, INRES-Pflanzenbau, Universität Bonn
Prof. Dr. Ingrid Kögel-Knabner, Dr. M. Steffens, Prof. Dr. Michael Schloter, Lehrstuhl für Bodenkunde, TU München
Prof. Dr. A. Schnepf, Prof. Dr. Jan Vanderborght, Prof. Jan van der Kruk, Dr. Charlotte Ockert, Dr. Roland Bol, FZ Jülich, Institut für Bio- und Geowissenschaften
Prof. Dr. Matthias Rillig, Abteilung für Pflanzenökologie, FU Berlin
Prof. Dr. Schulze-Lammers, Dr. Oliver Schmittmann, Institut für Landtechnik, Universität Bonn
Prof. Dr. Heiner Flessa, Dr. Axel Don, Thünen-Institut, Braunschweig
Dr. H. Gerdes, Ecologic Institute, Berlin
Project website:


Avatar Kemper

Dr. Roman Kemper


Auf dem Hügel 14

53121 Bonn

Avatar Neuhoff

Dr. Daniel Neuhoff

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