Professor Johan Six from ETH Zürich recently visited the University of KwaZulu-Natal as part of a collaboration with Crop Science’s Dr Alfred Odindo. During the visit, he presented a lecture on understanding sustainable agroecosystems for practice to some 40 academics and students.

Six is the Chair of the Sustainable Agroecosystems Group at ETH Zürich, with research focus on Landscape Analyses and Global Food Security.

UKZN and ETH Zürich are collaborating on trans-disciplinary, solutions-oriented research to simultaneously address problems of inadequate basic sanitation and food insecurity in growing informal settlements around urban centres like Durban. This can be done through developing technologies that close the agricultural nutrient cycle by developing safe nitrogen and potassium fertilisers from human excreta.

As part of this collaboration, ETH Zürich PhD candidate Mr Benjamin Wilde visited UKZN for one month as part of his work on the biophysical, social and policy aspects of using urine-based fertilisers as part of sustainable approaches to the management of waste.

Six spoke about his work on the complex interactions between soil, plants, soil biota (like fungi, bacteria, and earthworms), and the carbon and nitrogen cycles in terrestrial ecosystems, especially agroecosystems.

His general approach involves conducting inter- and transdisciplinary experimental work from the micro- to landscape scale and subsequently integrating it with modelling to interpolate and extrapolate it to the regional and global scale.

The modelling identifies knowledge gaps, generates testable hypotheses, and tests the mechanistic bases of biogeochemical models. Bio-economic modelling involves collaboration with economic and social scientists to holistically assess the sustainability and resilience of agriculture and food value chains.

Six gave fascinating examples from a diverse array of countries where he had conducted research, including the United States of America, the Democratic Republic of Congo, Uganda, Ghana, Indonesia, Thailand, Namibia and Honduras, to name a few.

He described management effects on soil greenhouse gases like nitrous oxide and carbon dioxide, and addressed the employment of conservation agriculture techniques. Six emphasised that the effectiveness of conservation agriculture requires that the basic three techniques are all applied: no-tillage practice, residue retention and crop rotation, which together help avoid yield losses.

He also spoke about agroecosystem-induced changes, factors affecting yield gaps in sub-Saharan Africa, agroforestry, erosion, climate smart agriculture and more.

Six spoke about the importance of including all the actors in a food system and building resilience through diversification. He added that consumers need to take responsibility and use their powers to determine what is produced and that it is done sustainably.

‘I really believe that what we’re going to have to do if we really want to make agriculture sustainable, is work with all the actors,’ said Six.

He concluded that sustainable agriculture is more about an integrated system where interactions between various role-players ensure food security. Its success, he said, is location-dependent and there are always trade-offs to achieve it.

Words: Christine Cuénod