The Deep Frontier project is an excellent example of thinking differently – instead of expanding arable land horizontally in order to meet the demand for an increased food production, the project is looking into vertical expansion, i.e. how we can utilize soil nutrients down to 5 meters in the ground.

Crops currently used for food production normally do not grow roots below 1.5 meters. Therefore, it is important to identify crops that are able to grow deeper roots and utilize nutrients in subsoil. Here perennial crops may play an important part. This also means that cropping systems in the future most likely will have to change.

The overall aim was to increase the exploitation of the subsoil resources by deep roots for enhancing food production in a sustainable way, where the need for resource input for food production and nutrient losses to the environment are reduced. In addition, the project aimed to contribute with research addressing climate change mitigation and improved soil biodiversity through the increased organic matter input to the soil, especially in deep soil layers.

The project’s specific research objectives were:

1.  Increase our understanding of how deep rooting can be achieved, and to identify deep rooted species and cropping systems with significant root activity between 2 and 4m.
2. Develop unique facilities for deep root research for this project, for inspiration and for attracting cooperation with other scientists, also after the project period.
3. Develop and test new methods for studying root growth and resource uptake (water and different plant nutrients) from deep soil layers (1 to 5m depth).
4. Quantify potential use of resources from the deep soil layers by different species and cropping systems and assess the potential environmental improvements in terms of nutrient cycling.
5. Study the effect of deeper and more permanent rooting on soil C storage, and develop DNA based methods for understanding root interaction with soil biology in deep soil during growth and subsequent decomposition.

In order to explore nutrients in soil and how deep roots utilize nutrients the Deep Frontier project has established facilities in which these factors can be studied - 12 root towers, each being 4 meters tall, and 24 field plots with a depth of 5 meters. These facilities have proven a unique opportunity for studying the potentials of deep rooted crops and deep rooted cropping systems.

The project found that there is clear species differences in root growth rates and in the ability to penetrate the deep soil layers, that intercropping and crop rotations can be used to promote deeper rooting of crops that growing perennial crops holds the potential of increasing the depth of the exploited root zone significantly, and that such intercropping systems could include the production of important annual crops while still achieving deep root exploitation by integrating with deep rooted perennials.

The methods developed combined with the facilities constructed allowed for detailed studies of water and nutrient uptake from deep soil layers, which have increased the understanding of the contribution and benefit of deep roots for crop yield and resilience, which previously have been limited. For example, the results indicate that dep rooting strongly increases the amount of water available to crops in dry periods, though there are still important gaps in our knowledge as to how much of the water is then actually being used; there is also indications of N-uptake from deep soil layers is almost as efficient as from the upper soil layers.

Numerus scientific papers have been published based on the research in Deep Frontier and many are still in preparation (please see the Publication and Dissemination List).

A key publication by is the position paper ‘Digging deeper for agricultural resources, the value of deep rooting’  prepared by the Deep Frontier senior researchers together with the members of the international Advisory Board.

  For more information on scientific papers please consult the Deep Frontier Publication and Dissemination List and the open-access repository Organic Eprints where a large number of the Deep Frontier publications are compiled.