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Department of Geography Soil Science and Biogeochemistry

Improving soil health in tropical regions

Healthy soils are key to maintaining ecosystem services provided by agriculture. New organic practices can help, but require incorporating traditional knowledge and the needs of local farmers. Researchers from the Department of Geography demonstrated this with an interdisciplinary and holistic research approach using compost and biochar in southwestern India.

Severin-Luca Bellè and a farmer sampling soil in the region Karnataka, southwestern India.

Climate change and the accelerated intensification of agriculture threaten food production and the livelihoods of farmers, especially in tropical regions. Soils are increasingly being exploited and cannot hold enough water and nutrients in the long-term, provide habitats for soil life or various other ecosystem services. 

An international research team led by the Department of Geography has now investigated how soils can be enhanced with locally available organic material in a tropical region in the state of Karnataka in southwestern India. Depending on the soil type and crops, this can be through sole or combined application of compost and biochar, plant residues converted to charcoal in the absence of oxygen. However, these findings can only be successfully implemented if the needs of local farmer communities are considered. In-depth interviews showed that long-term guidance and support is crucial for farmers, especially if higher yields are achieved only in subsequent years.

Tailor-made solutions

Traditional knowledge and practices of local farmer communities are also of high relevance. Farm households who have been burning their fields after harvesting (“slash-and-burn”) for generations, for example, were more open and positive towards the use of biochar as a fertiliser medium. "However, the influence of esteemed individuals of the village community should not be underestimated when evaluating the implementation of new practices," says Severin-Luca Bellè, PhD candidate and lead author of the study. 

In addition, the individual economic situation of a farmer plays an important role. Small-scale farmers in particular are often sceptical about new practices since they cannot risk crop failure. "They need to be accompanied closely with tailor-made solutions," says Bellè.

Milestone towards more sustainable agricultural practices

To ensure this long-term support, the researchers are now collaborating with local partners such as the Indian Institute of Science. Their future involvement will be limited to monitoring the soils. This study was the first to take a holistic approach at the natural and socio-economic aspects of organic fertilisation, thus laying an important milestone towards more sustainable agricultural practices.


Bellè S-L, Riotte J, Backhaus N, Sekhar M, Jouquet P, Abiven S (2022) Tailor-made biochar systems: Interdisciplinary evaluations of ecosystem services and farmer livelihoods in tropical agro-ecosystems. PLoS ONE 17(1): e0263302.


Weiterführende Informationen


Severin-Luca Bellè
Soil Science and Biogeochemistry
Department of Geography, University of Zurich
Tel. +41 44 63 56527


Samuel Abiven
Laboratoire de Géologie, Département de Géosciences
Ecole Normale Supérieure, Paris, France
Tel: +33 6 45 87 39 86


Norman Backhaus
Space, Nature and Society
Department of Geography, University of Zurich
Tel. +41 44 63 55 172