Indicators for sustainability of agricultural systems are a topical and widely debated issue. The Sustainable Development Goals (SDGs) have 230 indicators for sustainability, of which only 21 can be directly linked to agriculture (United Nations – Economic and Social Council 2016). The indicator ‘proportion of agricultural area under productive and sustainable agriculture’ (SDG 2, indicator 2.4.1, United Nations – Economic and Social Council 2016), directly raises the question as to the meaning of ‘productive and sustainable agriculture’. To meet SDG2 – Zero Hunger and Sustainable Food Systems – agricultural productivity must increase substantially, particularly in sub-Saharan Africa (SSA), to keep pace with the burgeoning population (Van Ittersum et al . 2016).
